Ballantine Books Edition, September 1997 ISBN: 0-345-37659-5 Sanned: !eember, "000 #$1$0 %ormatted &or 'ie(in) in *ord 97
+. S/N
.E B.E !2
#ISI2N 2% E N % E I N S + E
% 2 S noter (anderer, a o8r )eneration see *onders 8ndreamt$
S+E+% E.2I2N 2% E S2. SSE NOTABLE EARLY ACHIEVEMENTS
UNITED STATES
195; 1959 196" 196" 196" 196; 1969 1969 1971 1971 1973 1974 1974 1976
1977 19;1 19;019;4 19;5 19;6 19;9 199" 199" 1994
%irst sienti&i diso'er in spae-#an llen radiation belt (Explorer 1) %irst tele'ision ima)es o& te Eart &rom spae (Explorer 6) %irst sienti&i diso'er in interplanetar spae -diret obser'ation o& te solar (ind (Mariner 2) %irst sienti&iall s8ess&8l planetar mission (Mariner 2 to #en8s< %irst astronomial obser'ator in spae (OSO-1< %irst manned orbit o& anoter (orld =Apollo 8 to te oon< %irst landin) o& 8mans on anoter (orld =Apollo 11 to te oon< %irst samples ret8rned to Eart &rom anoter (orld =Apollo 11 to te oon< %irst manned ro'in) 'eile on anoter (orld =Apollo 15 to te oon< %irst spaera&t to orbit anoter planet (Mariner 9 to ars< %irst &lb o& >8piter (Pioneer 10) %irst d8al-planet mission (Mariner 10 to #en8s and er8r< %irst &lb o& er8r (Mariner 10) %irst s8ess&8l ars landin)? &irst spaera&t to sear &or li&e on anoter planet (Viking 1) %irst &lbs o& Sat8rn (Pioneer 11) %irst manned re8sable spaera&t =SS-1< %irst satellite to be retrie'ed, repaired, and redeploed in spae (Solar Maximum Miion) %irst distant ometar eno8nter (!n"erna"ional #ome"ar$ Explorer to +omet /iaobini-@immer< %irst &lb o& ran8s (Vo$ager "< %irst &lb o& Nept8ne (Vo$ager "< %irst detetion o& te eliopa8se (Vo$ager) %irst eno8nter (it a main-belt asteroid (%alileo to /aspra< %irst detetion o& a moon o& an asteroid "
(%alileo to Ida<
SOVIET UNION/RUSSIA
1957 %irst arti&iial satellite o& te Eart =Spu"nik 1< 1957 %irst animal in spae =Spu"nik 2< 1959 %irst spaera&t to esape te EartAs )ra'it =&una 1< 1959 %irst arti&iial planet o& te S8n =&una 1< 1959 %irst spaera&t to impat anoter (orld =&una 2 to te oon< 1959 %irst 'ie( o& te &ar side o& te moon =&una '< 1961 %irst 8man in spae =Vo"ok 1< 1961 %irst 8man to orbit te Eart =Vo"ok 1< 1961 %irst spaera&t to &l b oter planets =Venera 1 to #en8s? 196" Mar 1 to ars< 1963 %irst (oman in spae
Vo"ok 6< 1964 =%irst m8lti-person spae mission =Voko 1< 1965 %irst spae (alk =Voko "< 1966 %irst spaera&t to enter te atmospere o& anoter planet =Venera ' to #en8s< 1966 %irst spaera&t to orbit anoter (orld =&una 10 to te oon< 1966 %irst s8ess&8l so&t landin) on anoter (orld =&una 9 to te oon< 1970 %irst robot mission to ret8rn a sample &rom anoter (orld (&una 16 to te oon< 1970 %irst ro'in) 'eile on anoter (orld (&una 1* to te oon< 1971 %irst so&t landin) on anoter planet (Mar ' to ars< 197" %irst sienti&iall s8ess&8l landin) on anoter planet (Venera 8 to #en8s< 19;0 %irst approCimatel ear-lon) manned spae&li)t 19;1 =omparable to ars &li)t time< (So$u+ '5)
%irst &8ll orbital radar mappin) o& anoter planet (Venera 15 to #en8s< 19;5 %irst balloon station deploed in te atmospere o& a noter planet (Vega 1 to #en8s< 19;6 %irst lose ometar eno8nter 19;3
to alleAs +omet< %irst spae station inabited b rotatin) re(s
(Vega 1 19;6
(Mir)
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4
WANDERERS: AN INTRODUCTION B8t tell me, (o are te, tese (anderers $ $ $D GINE I I.E, E %I% E.E/ =19"3<
We (ere (anderers &rom te be)innin)$ *e kne( e'er stand o& tree &or a 8ndred miles$ *en te &r8its or n8ts (ere ripe, (e (ere tere$ *e &oll o(ed te erds in teir ann8a l mi)rations$ *e reHoied in &res meat$ tro8) stealt, &eint, amb8s, and main-&ore assa8lt, a &e( o& 8s ooperatin) aomplised (at man o& 8s, ea 8ntin) alone, o8ld not$ *e depended on one anoter$ akin) it on o8r o(n (as as l8diro8s to ima)ine as (as settlin) do(n$ *orkin) to)eter, (e proteted o8r ildren &rom te lions and te enas$ *e ta8)t tem te skills te (o8ld need$ nd te tools$ en, as no(, tenolo) (as te ke to o8r s8r'i'al$ *en te dro8)t (as prolon)ed, or (en an 8nsettlin) ill lin)ered in te s8mmer air, o8r )ro8p mo'ed onGsometimes to 8nkno(n lands$ *e so8)t a better plae$ nd (en (e o8ldnAt )et on (it te oters in o8r little nomadi band, (e le&t to &ind a more &riendl b8n some(ere else$ *e o8ld al(as be)in a)ain$ %or 99$9 perent o& te time sine o8r speies ame to be, (e (ere 8nters and &ora)ers, (anderers on te sa'annas and te steppes$ ere (ere no border )8ards ten, no 8stoms o&&iials$ e &rontier (as e'er(ere$ *e (ere bo8nded onl b te Eart and te oean and te skGpl8s oasional )r8mp nei)bors$ *en te limate (as on)enial, to8), (en te &ood (as plenti&8l, (e (ere (illin) to sta p8t$ nad'ent8ro8s$ 2'er(ei)t$ +areless$ In te last ten to8sand earsGan instant in o8r lon) istorG (eA'e abandoned te nomadi &i&e$ *eA'e domestiated te plants and animals$ * ase te &ood (en o8 an make it ome to o8D %or all its material ad'anta)es, te sedentar li&e as le&t 8s ed), 8n&8l&illed$ E'en a&ter 400 )enerations in 'illa)es and ities, (e a'enAt &or)otten$ e open road still so&tl alls, like a nearl &or)otten son) o& ildood$ *e in'est &ar-o&& plaes (it a ertain romane$ is appeal, I s8spet, as been meti8lo8sl ra&ted b nat8ral seletion as an essential element in o8r s8r'i'al$ .on) s8mmers, mild (inters, ri ar'ests, plenti&8l )ameGnone o& tem lasts &ore'er$ It is beond o8r po(ers to predit te &8t8re$ +atastropi e'ents a'e a (a o& sneakin) 8p on 8s, o& atin) 8s 8na(are$ o8r o(n li&e, or o8r bandAs, or e'en o8r speiesA mi)t be o(ed to a restless &e(Gdra(n, b a ra'in) te an ardl arti8late or 8nderstand, to 8ndiso'ered lands and ne( (orlds$ erman el'ille, in ob !ik, spoke &or (anderers in all epos and meridians: I am tormented (it an e'erlastin) it &or tin)s remote$ I lo'e to sail &orbidden seas $ $ $ o te anient /reeks and omans, te kno(n (orld omprised E8rope and an atten8ated sia and &ria, all s8rro8nded b an impassable *orld 2ean$ ra'elers mi)t eno8nter
5
in&erior bein)s alled barbarians or s8perior bein)s alled )ods$ E'er tree ad its drad, e'er distrit its le)endar ero$ B8t tere (ere not 'er man )ods, at least at &irst, peraps onl a &e( doen$ e li'ed on mo8ntains, 8nder te Eart, in te sea, or 8p tere in te sk$ e sent messa)es to people, inter'ened in 8man a&&airs, and interbred (it 8s$ s time passed, as te 8man eCplorator apait it its stride, tere (ere s8rprises: Barbarians o8ld be &8ll as le'er as /reeks and omans$ &ria and sia (ere lar)er tan anone ad )8essed$ e *orld 2ean (as not impassable$ ere (ere ntipodes$ 1 ree ne( ontinents eCisted, ad been settled b sians in a)es past, and te ne(s ad ne'er reaed E8rope$ lso te )ods (ere disappointin)l ard to &ind$ e &irst lar)e-sale 8man mi)ration &rom te 2ld *orld to te Ne( appened d8rin) te last ie a)e, aro8nd 11,500 ears a)o, (en te )ro(in) polar ie aps sallo(ed te oeans and made it possible to (alk on dr land &rom Siberia to laska$ to8sand ears later, (e (ere in ierra del %8e)o, te so8tern tip o& So8t meria$ .on) be&ore +ol8mb8s, Indonesian ar)ona8ts in o8tri))er anoes eCplored te (estern ai&i? people &rom Borneo settled ada)asar? E)ptians and .ibans ir8mna'i)ated &ria? and a )reat &leet o& oean )oin) H8nks &rom in) !nast +ina rissrossed te Indian 2ean, establised a base in @anibar, ro8nded te +ape o& /ood ope, and entered te tlanti 2ean$ In te &i&teent tro8) se'enteent ent8ries, E8ropean sailin) sips diso'ered ne( ontinents =ne(, at an rate, to E8ropeans< and ir8mna'i)ated te planet$ In te ei)teent and nineteent ent8ries, merian and 8ssian eCplorers, traders, and settlers raed (est and east aross t(o 'ast ontinents to te ai&i$ is est to eCplore and eCploit, o(e'er to8)tless its a)ents ma a'e been, as lear s8r'i'al 'al8e$ It is not restrited to an one nation or etni )ro8p$ It is an endo(ment tat all members o& te 8man speies old in ommon$ Sine (e &irst emer)ed, a &e( million ears a)o in East &ria, (e a'e meandered o8r (a aro8nd te planet$ ere are no( people on e'er ontinent and te remotest islands, &rom pole to pole, &rom o8nt E'erest to te !ead Sea, on te oean bottoms and e'en, oasionall, in residene "00 miles 8pG8mans, like te )ods o& old, li'in) in te sk$ ese das tere seems to be no(ere le&t to eCplore, at least on te land area o& te Eart$ #itims o& teir 'er s8ess te eCplorers no( prett m8 sta ome$ #ast mi)rations o& peopleGsome 'ol8ntar, most notG a'e saped te 8man ondition$ ore o& 8s &lee &rom (ar, oppression, and &amine toda tan at an oter time in 8man istor$ s te EartAs limate an)es in te omin) deade$ tere are likel to be &ar )reater n8mbers o& en'ironmental re&8)ees$ Better plaes (ill al(as all to 8s$ ides o& people (ill ontin8e to ebb and &lo( aross te planet$ B8t te lands (e r8n to no( a'e alread been settled$ 2ter people, o&ten 8nsmpateti to o8r pli)t, are tere be&ore 8s$ J
J
J
1
s to te &able tat tere are ntipodes, (rote St$ 8)8stine in te &i&t ent8r, tat is to sa, men on te opposite side o& te eart, (ere te s8n rises (en it sets to 8s, men (o (alk (it teir &eet opposite o8rs, tat is on IAll )ro8nd redible$ E'en i& some 8nkno(n landmass is tere, and not H8st oean, tere (as onl one pair o& ori)inal anestors, and it is inonei'able tat s8 distant re)ions so8ld a'e been peopled b damAs desendants$AA
6
, .eib LATE IN THE NINETEENTH CENTURY
/r8ber (as )ro(in) 8p 111 +entral E8rope, in an obs8re to(n in te immense, pol)lot, anient 8stro-8n)arian Empire$ is &ater sold &is (en e o8ld$ B8t times (ere o&ten ard$ s a o8n) man, te onl onest emploment .eib o8ld &ind (as arrin) people aross te nearb ri'er B8)$ e 8stomer, male or &emale, (o8ld mo8nt .eibAs bak? in is pried boots, te tools o& is trade, e (o8ld (ade o8t in a sallo( stret o& te ri'er and deli'er is passen)er to te opposite bank$ Sometimes te (ater reaed is (aist$ ere (ere no brid)es ere, no &errboats$ orses mi)t a'e ser'ed te p8rpose, b8t te ad oter 8ses$ at le&t .eib and a &e( oter o8n) men like im$ e ad no oter 8ses$ No oter (ork (as a'ailable$ e (o8ld lo8n)e abo8t te ri'erbank, allin) o8t teir pries, boastin) to potential 8stomers abo8t te s8periorit o& teir draa)e$ e ired temsel'es o8t like &o8r-&ooted animals$ )rand&ater (as a beast o& b8rden I donAt tink tat in all is o8n) manood .eib ad 'ent8red more tan a 8ndred kilometers &rom is little ometo(n o& Sasso($ B8t ten, in 1904, e s8ddenl ran a(a to te Ne( *orld to a'oid a m8rder rap, aordin) to one &amil le)end$ e le&t is o8n) (i&e beind$ o( di&&erent &rom is tin bak-(ater amlet te )reat /erman port ities m8st a'e seemed, o( 'ast te oean, o( stran)e te lo&t sksrapers and endless 8b-b8b o& is ne( land$ *e kno( notin) o& is rossin), b8t a'e &o8nd te sipAs mani&est &or te Ho8rne 8ndertaken later b is (i&e, +aia Hoinin) .eib a&ter e ad sa'ed eno8) to brin) er o'er$ Se tra'eled in te eapest lass on te Bata'ia, a 'essel o& amb8r) re)istr$ ereAs sometin) eartbreakin)l terse abo8t te do8ment: +an se read or (riteD No$ +an se speak En)lisD No$ o( m8 mone does se a'eD I an ima)ine er '8lnerabilit and er same as se replies, 2ne dollar$ Se disembarked in Ne( ork, (as re8nited (it .eib, li'ed H8st lon) eno8) to )i'e birt to m moter and er sister, and ten died &rom ompliations o& ildbirt$ In tose &e( ears in meria, er name ad sometimes been an)liied to +lara$ K8arter ent8r later, m moter named er o(n &irstborn, a son, a&ter te moter se ne'er kne($
OUR DISTANT ANCESTORS , (atin)
te stars, noted &i'e tat did more tan rise and set in stolid proession, as te so-alled &iCed stars did$ ese &i'e ad a 8rio8s and ompleC motion$ 2'er te monts te seemed to (ander slo(l amon) te stars$ Sometimes te did loops$ oda (e all tem planets, te /reek (ord &or (anderers$ It (as, I ima)ine, a pe8liarit o8r anestors o8ld relate to$ *e kno( no( tat te planets are not stars, b8t oter (orlds, )ra'itationall lased to te S8n$ >8st as te eCploration o& te Eart (as bein) ompleted, (e be)an to reo)nie it as one (orld amon) an 8no8nted m8ltit8de o& oters, irlin) te S8n or orbitin) te oter stars tat make 8p te ilk *a )alaC$ 28r planet and o8r solar sstem are s8rro8nded b a ne( (orld oean te depts o& spae$ It is no more impassable tan te last$ abe itAs a little earl$ abe te time is not K8ite et$ B8t tose oter (orldsG promisin) 8ntold opport8nitiesGbekon$ In te last &e( deades, te nited States and te &ormer So'iet nion a'e aomplised sometin) st8nnin) and istoriGte lose-8p eCamination o& all tose points o& li)t, &rom er8r to Sat8rn, tat mo'ed o8r anestors to (onder and to siene$ Sine te ad'ent o& s8ess&8l interplanetar &li)t in 196", o8r maines a'e &lo(n b, orbited, or landed
7
on more tan se'ent ne( (orlds$ *e a'e (andered amon) te (anderers$ *e a'e &o8nd 'ast 'olani eminenes tat d(ar& te i)est mo8ntain on Eart? anient ri'er 'alles on t(o planets eni)matiall one too old and te oter too ot &or r8nnin) (ater? a )iant planet (it an interior o& liK8id metalli dro)en into (i a to8sand Earts (o8ld &it? (ole moons tat a'e melted? a lo8d-o'ered plae (it an atmospere o& orrosi'e raids, (ere e'en te i) platea8s are abo'e te meltin) point o& lead anient s8r&aes on (i a &ait&8l reord o& te 'iolent &ormation o& te Solar Sstem is en)ra'ed? re&8)ee ie (orlds &rom te transpl8tonian depts? eCK8isitel patterned rin) sstems, markin) te s8btle armonies o& )ra'it? and a (orld s8rro8nded b lo8ds o& ompleC or)ani mole8les like tose tat m te earliest istor o& o8r planet led to te ori)in o& li&e$ Silentl, te orbit te S8n, (aitin)$ *e a'e 8no'ered (onders 8ndreamt b o8r anestors (o &irst spe8lated on te nat8re o& tose (anderin) li)ts in te ni)t sk$ *e a'e probed te ori)ins o& o8r planet and o8rsel'es$ B diso'erin) (at else is possible, b omin) &ae to &ae (it alternati'e &ates o& (orlds more or less like o8r o(n, (e a'e be)8n to better 8nderstand te Eart$ E'er one o& tese (orlds is lo'el and instr8ti'e$ B8t, so &ar as (e kno(, te are also, e'er one o& tem, desolate and barren$ 28t tere, tere are no better plaes$ So &ar, at least$ !8rin) te #ikin) roboti mission, be)innin) in >8l 1976, in a ertain sense I spent a ear on ars$ I eCamined te bo8lders and sand d8nes, te sk red e'en at i) noon, te anient ri'er 'alles, te soarin) 'olani mo8ntains, te &iere (ind erosion, te laminated polar terrain, te t(o dark potato-saped moons$ B8t tere (as no li&eGnot a riket or a blade o& )rass, or e'en, so &ar as (e an tell &or s8re, a mirobe$ ese (orlds a'e not been )raed, as o8rs as, b li&e$ .i&e is a omparati'e rarit$ o8 an s8r'e doens o& (orlds and &ind tat on onl one o& tem does li&e arise and e'ol'e and persist$ a'in) in all teir li'es till ten rossed notin) (ider tan a laer, .eib and +aia )rad8ated to rossin) oeans$ e ad one )reat ad'anta)e: 2n te oter side o& te (aters tere (o8ld be-in'ested (it o8tlandis 8stoms, it is tr8eGoter 8man bein)s speakin) teir lan)8a)e and sarin) at least some o& teir 'al8es, e'en people to (om te (ere losel related$ In o8r time (eA'e rossed te Solar Sstem and sent &o8r sips to te stars$ Nept8ne lies a million times &arter &rom Eart tan Ne( ork +it is &rom te banks o& te B8)$ B8t tere are no distant relati'es, no 8mans, and apparentl no li&e (aitin) &or 8s on tose oter (orlds$ No letters on'eed b reent Lmi)r Ls elp 8s to 8nderstand te ne( landG onl di)ital data transmitted at te speed o& li)t b 8n&eelin), preise robot emissaries$ e tell 8s tat tese ne( (orlds are not m8 like ome$ B8t (e ontin8e to sear &or inabitants$ *e anAt elp it$ .i&e looks &or li&e$ No one on Eart, not te riest amon) 8s, an a&&ord te passa)e? so (e anAt pik 8p and lea'e &or ars or itan on a (im, or bea8se (eAre bored, or o8t o& (ork, or dra&ted into te arm, or oppressed, or bea8se, H8stl or 8nH8stl, (eA'e been a8sed o& a rime$ ere does not seem to be s8&&iient sort-term pro&it to moti'ate pri'ate ind8str$ I& (e 8mans e'er )o to tese (orlds, ten, it (ill be bea8se a nation or a onsorti8m o& tem belie'es it to be to its ad'anta)e Gor to te ad'anta)e o& te 8man speies$ >8st no(, tere are a )reat man matters pressin) in on 8s tat ompete &or te mone it takes to send people to oter (orlds$
;
atAs (at tis book is abo8t: oter (orlds, (at a(aits 8s on tem, (at te tell 8s abo8t o8rsel'es, andG)i'en te 8r)ent problems o8r speies no( &aesG(eter it makes sense to )o$ So8ld (e sol'e tose problems &irstD 2r are te a reason &or )oin)D is book is, in man (as, optimisti abo8t te 8man prospet$ e earliest apters ma at &irst si)t seem to re'el o'erm8 in o8r imper&etions$ B8t te la an essential spirit8al and lo)ial &o8ndation &or te de'elopment o& m ar)8ment$ I a'e tried to present more tan one &aet o& an iss8e$ ere (ill be plaes (ere I seem to be ar)8in) (it msel&$ I am$ Seein) some merit to more tan one side, I o&ten ar)8e (it msel&$ I ope b te last apter it (ill be lear (ere I ome o8t$ e plan o& te book is ro8)l tis: *e &irst eCamine te (idespread laims made o'er all o& 8man istor tat o8r (orld and o8r speies are 8niK8e, and e'en entral to te (orkin)s and p8rpose o& te +osmos$ *e 'ent8re tro8) te Solar Sstem in te &ootsteps o& te latest 'oa)es o& eCploration and diso'er, and ten assess te reasons ommonl o&&ered &or sendin) 8mans into spae$ In te last and most spe8lati'e part o& te book, I trae o( I ima)ine tat o8r lon)-term &8t8re in spae (ill (ork itsel& o8t$ ale Bl8e !ot is abo8t a ne( reo)nition, still slo(l o'ertakin) 8s, o& o8r oordinates, o8r plae in te ni'erse and o(, e'en i& te all o& te open road is m8ted in o8r time, a entral element o& te 8man &8t8re lies &ar beond te Eart$
9
+
E
1
YOU ARE HERE e entire Eart is b8t a point, and te plae o& o8r o(n abitation b8t a min8te orner o& it$ G+S E.IS, 2N EE2, ME.!/A/!OS, B22 4 =+$ 170<
s te astronomers 8nanimo8sl tea, te ir8it o& te (ole eart, (i to 8s seems endless, ompared (it te )reatness o& te 8ni'erse as te likeness o& a mere tin point$ GINS +E..INS +$ 330-395, E .S >2 2N IS2IN, IN /E #O!#&E O EVE/S
Te spaera&t (as a lon) (a &rom
ome, beond te orbit o& te o8termost planet and i) abo'e te elipti planeG(i is an ima)inar &lat s8r&ae tat (e an tink o& as sometin) like a raetrak in (i te orbits o& te planets are mainl on&ined$ e sip (as speedin) a(a &rom te S8n at 40,000 miles per o8r$ B8t in earl %ebr8ar o& 1990, it (as o'ertaken b an 8r)ent messa)e &rom Eart$ 2bedientl, it t8rned its ameras bak to(ard te no(-distant planets$ Sle(in) its san plat&orm &rom one spot in te sk to anoter, it snapped 60 pit8res and stored tem in di)ital &orm on its tape reorder$ en, slo(l, in ar, pril, and a, it radioed te data bak to Eart$ Ea ima)e (as omposed o& 640,000 indi'id8al pit8re elements =piCels<, like te dots in a ne(spaper (ire-poto or a pointillist paintin)$ e spaera&t (as 3$7 billion miles a(a &rom Eart, so &ar a(a tat it took et piCel 5M o8rs, tra'elin) at te speed o& li)t, to rea 8s$ e pit8res mi)t a'e been ret8rned earlier, b8t te bi) radio telesopes in +ali&ornia, Spain, and 8stralia tat reei'e tese (ispers &rom te ed)e o& te Solar Sstem ad responsibilities to oter sips tat pl te sea o& spae amon) tem, a)ellan, bo8nd &or #en8s, and /alileo on its tort8o8s passa)e to >8piter$ Vo$ager 1 (as so i) abo'e te elipti plane bea8se, in 19;1, it ad made a lose pass b itan, te )iant moon o& Sat8rn$ Its sister sip, Vo$ager 2, (as dispated on a di&&erent traHetor, (itin te elipti plane, and so se (as able to per&orm er elebrated eCplorations o& ran8s and Nept8ne e t(o Vo$ager robots a'e eCplored &o8r planets and nearl siCt moons$ e are tri8mps o& 8man en)ineerin) an$ one o& te )lories o& te merian spae pro)ram$ e (ill e in te istor books (en m8 else abo8t o8r time &or)otten$ e Vo$ager (ere )8aranteed to (ork onl 8ntil te Sat8rn eno8nter$ I to8)t it mi)t be a )ood idea, H8st a&ter Sat8rn, to a'e tem take one last )lane ome(ard$ %rom Sat8rn, I kne( te Eart (o8ld appear too small &or Vo$ager to make o8t an detail$ 28r planet (o8ld be H8st a point o& li)t, a lonel piCel, ardl distin)8isable &rom te man oter points o& li)t Vo$ager o8ld see, nearb planets and &ar-o&& s8ns$ B8t preise bea8se o& te obs8rit o& o8r (orld t8s re'ealed, s8 pit8re mi)t be (ort a'in)$
10
ariners ad painstakin)l mapped te oastlines o& te ontinents$ /eo)rapers ad translated tese &indin)s into arts and )lobes$ oto)raps o& tin pates o& te Eart ad been obtained &irst b balloons and airra&t, ten b rokets in brie& ballisti &li)t, and at last b orbitin) spaera&tG)i'in) a perspeti'e like te one o8 aie'e b positionin) o8r eeball abo8t an in abo'e a lar)e )lobe$ *ile almost e'erone is ta8)t tat te Eart is a spere (it all o& 8s someo( )l8ed to it b )ra'it, te realit o& o8r ir8mstane did not reall be)in to sink in 8ntil te &amo8s &rame-&illin) pollo poto)rap o& te (ole EartGte one taken b te pollo 17 astrona8ts on te last Ho8rne o& 8mans to te oon$ It as beome a kind o& ion o& o8r a)e$ ereAs ntartia at (at merians and E8ropeans so readil re)ard as te bottom, and ten all o& &ria stretin) 8p abo'e it: o8 an see Etiopia, anania, and ena, (ere te earliest 8mans li'ed$ t top ri)t are Sa8di rabia and (at E8ropeans all te Near East$ >8st barel peekin) o8t at te top is te editerranean Sea, aro8nd (i so m8 o& o8r )lobal i'iliation emer)ed$ o8 an make o8t te bl8e o& te oean, te ello(-red o& te Saara and te rabian desert, te bro(n-)reen o& &orest and )rassland$ nd et tere is no si)n o& 8mans in tis pit8re, not o8r re(orkin) o& te EartAs s8r&ae, not o8r maines, not o8rsel'es: *e are too small and o8r statera&t is too &eeble to be seen b a spaera&t bet(een te Eart and te oon$ %rom tis 'anta)e point, o8r obsession (it nationalism is no(ere in e'idene$ e pollo pit8res o& te (ole Eart on'eed to m8ltit8des sometin) (ell kno(n to astronomers: 2n te sale o& (orldsGto sa notin) o& stars or )alaCiesG8mans are inonseK8ential, a tin &ilm o& li&e on an obs8re and solitar l8mp o& rok and metal$ It seemed to me tat anoter pit8re o& te Eart, tis one taken &rom a 8ndred to8sand times &arter a(a, mi)t elp in te ontin8in) proess o& re'ealin) to o8rsel'es o8r tr8e ir8mstane and ondition$ It ad been (ell 8nderstood b te sientists and pilosopers o& lassial antiK8it tat te Eart (as a mere point in a 'ast enompassin) +osmos, b8t no one ad e'er seen it as s8$ ere (as o8r &irst ane =and peraps also o8r last &or deades to ome<$ an in NSAs Vo$ager roHet (ere s8pporti'e$ B8t &rom te o8ter Solar Sstem te Eart lies 'er near te S8n, like a mot entralled aro8nd a &lame$ !id (e (ant to aim te amera so lose to te S8n as to risk b8rnin) o8t te spaera&tAs 'idion sstemD *o8ldnAt it be better to dela 8ntil all te sienti&i ima)es &rom ran8s and Nept8ne, i& te spaera&t lasted tat lon), (ere takenD nd so (e (aitedG and a )ood tin) tooG&rom 19;1 at Sat8rn, to 19;6 at ran8s, to 19;9, (en bot spaera&t ad passed te orbits o& Nept8ne and l8to$ t last te time ame B8t tere (ere a &e( instr8mental alibrations tat needed to be done &irst, and (e (aited a little lon)er$ lto8) te spaera&t (ere in te ri)t spots, te instr8ments (ere still (orkin) bea8ti&8ll, and tere (ere no oter pit8res to take, a &e( proHet personnel opposed it$ It (asnAt siene, te said$ en (e diso'ered tat te teniians (o de'ise and transmit te radio ommands to Vo$ager (ere, in a as-strapped NS, to be laid o&& immediatel or trans&erred to oter Hobs$ I& te pit8re (ere to be taken, it ad to be done ri)t ten$ t te last min8te at8all, in te midst o& te Vo$ager 2 eno8nter (it Nept8ne, te ten NS dministrator, ear dmiral iard r8l, stepped in and made s8re tat tese ima)es (ere obtained$ e
11
spae sientists +and ansen o& NSAs >et rop8lsion .aborator =>.< and +aroln oro o& ni'ersit o& riona desi)ned te ommand seK8ene and al8lated te amera eCpos8re times$ So ere te areGa mosai o& sK8ares laid do(n on top o& te planets and a bak)ro8nd smatterin) o& more distant stars$ *e (ere able to poto)rap not onl te Eart, b8t also &i'e oter o& te S8nAs nine kno(n planets$ er8r, te innermost, (as lost in te )lare o& te S8n, and ars and l8to (ere too small, too diml lit, andor too &ar a(a$ ran8s and Nept8ne are so dim tat to reord teir presene reK8ired lon) eCpos8res? aordin)l, teir ima)es (ere smeared bea8se o& spaera&t motion$ is is o( te planets (o8ld look to an alien spaesip approain) te Solar Sstem a&ter a lon) interstellar 'oa)e$ %rom tis distane te planets seem onl points o& li)t, smeared or 8nsmearedGe'en tro8) te i)-resol8tion telesope aboard Vo$ager$ e are like te planets seen (it te naked ee &rom te s8r&ae o& te EartGl8mino8s dots, bri)ter tan most o& te stars$ 2'er a period o& monts te Eart, like te oter planets, (o8ld seem to mo'e amon) te stars$ o8 annot tell merel b lookin) at one o& tese dots (at itAs like, (atAs on it, (at its past as been, and (eter, n tis parti8lar epo, anone li'es tere$ Bea8se o& te re&letion o& s8nli)t o&& te spaera&t, te Eart seems to be sittin) in a beam o& li)t, as i& tere (ere some speial si)ni&iane to tis small (orld$ B8t itAs H8st an aident o& )eometr and optis$ e S8n emits its radiation eK8itabl in all diretions$ ad te pit8re been taken a little earlier or a little later, tere (o8ld a'e been no s8nbeam i)li)tin) te Eart$ nd ( tat er8lean olorD e bl8e omes partl &rom te sea, partl &rom te sk$ *ile (ater in a )lass is transparent, It absorbs sli)tl more red li)t tan bl8e$ I& o8 a'e tens o& meters o& te st8&& or more, te red li)t is absorbed o8t and (at )ets re&leted bak to spae is mainl bl8e$ In te same (a, a sort line o& si)t tro8) air seems per&etl transparent$ Ne'ertelessGsometin) .eonardo da #ini eCelled at portrain)Gte more distant te obHet, te bl8er it seems$ *D Bea8se te air satters bl8e li)t aro8nd m8 better tan it does red$ So te bl8is ast o& tis dot omes &rom its tik b8t transparent atmospere and its deep oeans o& liK8id (ater$ nd te (iteD e Eart on an a'era)e da is abo8t al& o'ered (it (ite (ater lo8ds$ *e an eCplain te (an bl8eness o& tis little (orld bea8se (e kno( it (ell$ *eter an alien sientist ne(l arri'ed at te o8tskirts o& o8r solar sstem o8ld reliabl ded8e oeans and lo8ds and a tikis atmospere is less ertain$ Nept8ne, &or instane, is bl8e, b8t ie&l &or di&&erent reasons$ %rom tis distant 'anta)e point, te Eart mi)t not seem o& an parti8lar interest$ B8t &or 8s, itAs di&&erent$ .ook a)ain at tat dot$ atAs ere$ atAs ome$ atAs 8s$ 2n it e'erone o8 lo'e, e'erone o8 kno(, e'erone o8 e'er eard o&, e'er 8man bein) (o e'er (as, li'ed o8t teir li'es$ e a))re)ate o& o8r Ho and s8&&erin), to8sands o& on&ident reli)ions, ideolo)ies, and eonomi dotrines, e'er 8nter and &ora)er, e'er ero and o(ard, e'er reator and destroer o& i'iliation, e'er kin) and peasant, e'er o8n) o8ple in lo'e, e'er mot and &ater, ope&8l ild, in'entor and eCplorer, e'er teaer o& morals, e'er orr8pt politiian, e'er s8perstar,O e'er s8preme leader, e'er saint and sinner in te istor o& o8r speies li'ed tereGon a mote o& d8st s8spended in a s8nbeam$
1"
e Eart is a 'er small sta)e in a 'ast osmi arena$ ink o& te ri'ers o& blood spilled b all tose )enerals and emperors so tat, in )lor and tri8mp, te o8ld beome momentar masters o& a &ration o& a dot$ ink o& te endless 'isited b te inabitants o& one orner o& tis piCel te sarel distin)8isable inabitants o& some oter orner, o( &reK8ent teir mis8nderstandin)s, o( ea)er te are to kill one anoter, o( &er'ent teir atreds$ 28r post8rin)s, o8r ima)ined sel&-importane, te del8sion tat (e a'e some pri'ile)ed position in te ni'erse, are allen)ed b tis point o& pale li)t$ 28r planet is a lonel spek in te )reat en'elopin) osmi dark$ In o8r obs8rit, in all tis 'astness, tere is no int tat elp (ill ome &rom else(ere to sa'e 8s &rom o8rsel'es$ e Eart is te onl (orld kno(n so &ar to arbor li&e$ ere is no(ere else, at least in te near &8t8re, to (i o8r speies o8ld mi)rate$ #isit, es$ Settle, not et$ .ike it or not, &or te moment te Eart is (ere (e make o8r stand$ It as been said tat astronom is a 8mblin) and arater-b8ildin) eCperiene$ ere is peraps no better demonstration o& te &oll o& 8man oneits tan tis distant ima)e o& o8r tin (orld$ o me, it 8ndersores o8r responsibilit to deal more kindl (it one anoter, and to preser'e and eris te pale bl8e dot, te onl ome (eA'e e'er kno(n$
13
+
E
"
ABBERATIONS OF LIGHT I& man (ere taken a(a &rom te (orld, te rest (o8ld seem to be all astra, (ito8t aim or p8rpose $ $ $ and to be leadin) to notin)$ G%N+IS B+2N
, WISDOM OF THE ANCIENTS (1619)
Ann !r8an s8))ests an eCperiment: .ook bak a)ain at te pale bl8e dot o& te preedin) apter$ ake a )ood lon) look at it$ Stare at te dot &or an len)t o& time and ten tr to on'ine o8rsel& tat /od reated te (ole ni'erse &or one o& te 10 million or so speies o& li&e tat inabit tat spek o& d8st$ No( take it a step &8rter: Ima)ine tat e'ertin) (as made H8st &or a sin)le sade o& tat speies, or )ender, or etni or reli)io8s s8bdi'ision$ I& tis doesnAt strike o8 as 8nlikel, pik anoter dot$ Ima)ine it to be inabited b a di&&erent &orm o& intelli)ent li&e$ e, too, eris te notion o& a /od (o as reated e'ertin) &or teir bene&it$ o( serio8sl do o8 take teir laimD PSEE SD o8 mean te bri)t red oneD is da8)ter asks in ret8rn$ es$ o8 kno(, it mi)t not be tere anmore$ It mi)t be )one b no(GeCploded or sometin)$ Its li)t is still rossin) spae, H8st reain) o8r ees no($ B8t (e donAt see it as it is$ *e see it as it (as$ an people eCperiene a stirrin) sense o& (onder (en te &irst on&ront tis simple tr8t$ *D * so8ld it be so ompellin)D 2n o8r little (orld li)t tra'els, &or all pratial p8rposes, instantaneo8sl$ I& a li)tb8lb is )lo(in), ten o& o8rse itAs psiall (ere (e see it, sinin) a(a$ *e rea o8t o8r and and to8 it: ItAs tere all ri)t, and 8npleasantl ot$ I& te &ilament &ails, ten te li)t )oes o8t$ *e donAt see it in te same plae, )lo(in), ill8minatin) te room ears a&ter te b8lb breaks and itAs remo'ed &rom its soke t$ e 'er notion seems nonsensial$ B8t i& (eAre &ar eno8) a(a, an entire s8n an )o o8t and (eAll ontin8e to see it sinin) bri)tl? (e (onAt learn o& its deat, it ma be, &or a)es to omeGin &at, &or o( lon) it takes li)t, (i tra'els &ast b8t not in&initel &ast, to ross te inter'enin) 'astness$ e immense distanes to te stars and te )alaCies mean tat (e see e'ertin) in spae in te pastGsome as te (ere be&ore te Eart ame to be$ elesopes are time maines$ .on) a)o, (en an earl )alaC be)an to po8r li)t o8t into te s8rro8ndin) darkness, no (itness o8ld a'e kno(n tat billions o& ears later some remote l8mps o& rok and metal, ie and or)ani mole8les (o8ld &all to)eter to make a plae alled Eart? or tat li&e (o8ld arise and tinkin)
14
bein)s e'ol'e (o (o8ld one da apt8re a little o& tat )alati li)t, and tr to p8le o8t (at ad sent it on its (a$ nd a&ter te Eart dies, some 5 billion ears &rom no(, a&ter it is b8rned to a risp or e'en s(allo(ed b te S8n, tere (ill be oter (orlds and stars and )alaCies omin) into bein)G and te (ill kno( notin) o& a plae one alled Eart$ IT ALMOST NEVER FEELS like
preH8die$ Instead, it seems &ittin) and H8stGte idea tat, bea8se o& an aident o& birt, o8r )ro8p =(ie'er one it is< so8ld a'e a entral position in te soial 8ni'erse$ mon) araoni prinelin)s and lanta)enet pretenders, ildren o& robber barons and +entral +ommittee b8rea8rats, street )an)s and onK8erors o& nations, members o& on&ident maHorities, obs8re sets, and re'iled minorities, tis sel&-ser'in) attit8de seems as nat8ral as breatin)$ It dra(s s8stenane &rom te same psi (ellsprin)s as seCism, raism, nationalism, and te oter deadl a8'inisms tat pla)8e o8r speies$ nommon stren)t o& arater is needed to resist te blandisments o& tose (o ass8re 8s tat (e a'e an ob'io8s, e'en /od)i'en, s8periorit o'er o8r &ello(s$ e more preario8s o8r sel&-esteem, te )reater o8r '8lnerabilit to s8 appeals$ Sine sientists are people, it is not s8rprisin) tat omparable pretensions a'e insin8ated temsel'es into te sienti&i (orld'ie($ Indeed, man o& te entral debates in te istor o& siene seem to be, in part at least, ontests o'er (eter 8mans are speial$ lmost al(as, te )oin)-in ass8mption is tat (e are speial$ &ter te premise is losel eCamined, to8), it t8rns o8tGin diseartenin)l man asesGtat (e are not$ 28r anestors li'ed o8t o& doors$ e (ere as &amiliar (it te ni)t sk as most o& 8s are (it o8r &a'orite tele'ision pro)rams$ e S8n, te oon, te stars, and te planets all rose in te east and set in te (est, tra'ersin) te sk o'eread in te interim$ e motion o& te ea'enl bodies (as not merel a di'ersion, eliitin) a re'erential nod and )r8nt? it (as te onl (a to tell te time o& da and te seasons$ %or 8nters and )aterers, as (ell as &or a)ri8lt8ral peoples, kno(in) abo8t te sk (as a matter o& li&e and deat$ o( l8k &or 8s tat te S8n, te oon, te planets, and te stars are part o& some ele)antl on&i)8red osmi lok(orkF It seemed to be no aident$ e (ere p8t ere &or a p8rpose, &or o8r bene&it$ *o else makes 8se o& temD *at else are te )ood &orD nd i& te li)ts in te sk rise and set aro8nd 8s, isnAt it e'ident tat (eAre at te enter o& te ni'erseD ese elestial bodiesGso learl s8&&8sed (it 8neartl po(ers, espeiall te S8n on (i (e depend &or li)t and eatGirle 8s like o8rtiers &a(nin) on a kin)$ E'en i& (e ad not alread )8essed, te most elementar eCamination o& te ea'ens re'eals tat (e are speial$ e ni'erse seems desi)ned &or 8man bein)s$ ItAs di&&i8lt to ontemplate tese ir8mstanes (ito8t eCperienin) stirrin)s o& pride and reass8rane$ e entire ni'erse, made &or 8sF *e m8st reall be sometin)$ is satis&in) demonstration o& o8r importane, b8ttressed b dail obser'ations o& te ea'ens, made te )eoentrist oneit a trans8lt8ral tr8tGta8)t in te sools, b8ilt into te lan)8a)e, part and parel o& )reat literat8re and sared sript8re$ !issenters (ere diso8ra)ed, sometimes (it tort8re and deat$ It is no (onder tat &or te 'ast b8lk o& 8man istor, no one K8estioned it$
15
It (as do8btless te 'ie( o& o8r &ora)in) and 8ntin) anestors$ e )reat astronomer o& antiK8it, +la8di8s tolemae8s =tolem<, in te seond ent8r kne( tat te Eart (as a spere, kne( tat its sie (as a point ompared to te distane o& te stars, and ta8)t tat it la ri)t in te middle o& te ea'ens$ ristotle, lato, St$ 8)8stine, St$ omas K8inas, and almost all te )reat pilosopers and sientists o& all 8lt8res o'er te 3,000 ears endin) in te se'enteent ent8r bo8)t into tis del8sion$ Some b8sied temsel'es &i)8rin) o8t o( te S8n, te oon, te stars, and te planets o8ld be 8nnin)l attaed to per&etl transparent, rstalline speresGte bi) speres, o& o8rse, entered on te EartGtat (o8ld eCplain te ompleC motions o& te elestial bodies so meti8lo8sl roniled b )enerations o& astronomers$ nd te s8eeded: *it later modi&iations, te )eoentri potesis adeK8atel ao8nted &or te &ats o& planetar motion as kno(n in te seond ent8r, and in te siCteent$ %rom tere it (as onl a sli)t eCtrapolation to an e'en more )randiose laimGtat te per&etion o& te (orld (o8ld be inomplete (ito8t 8mans, as lato asserted in te imae8s$ an $ $ $ is all, te poet and leri >on !onne (rote in 16"5$ e is not a piee o& te (orld, b8t te (orld itsel&? and neCt to te )lor o& /od, te reason ( tere is a (orld$ nd etGne'er mind o( man kin)s, popes, pilosopers, sientists, and poets insisted on te ontrarGte Eart tro8) tose millennia st8bbornl persisted in orbitin) te S8n$ o8 mi)t ima)ine an 8naritable eCtraterrestrial obser'er lookin) do(n on o8r speies o'er all tat timeG(it 8s eCitedl atterin), e ni'erse is reated &or 8sF *eAre at te enterF E'ertin) pas oma)e to 8sFGand onl8din) tat o8r pretensions are am8sin), o8r aspirations pateti, tat tis m8st be te planet o& te idiots$ B8t s8 a H8d)ment is too ars$ *e did te best (e o8ld$ ere (as an 8nl8k oinidene bet(een e'erda appearanes and o8r seret opes$ *e tend not to be espeiall ritial (en presented (it e'idene tat seems to on&irm o8r preH8dies$ nd tere (as little o8nter'ailin) e'idene$ In m8ted o8nterpoint, a &e( dissentin) 'oies, o8nselin) 8milit and perspeti'e, o8ld be eard do(n tro8) te ent8ries$ t te da(n o& siene, te atomist pilosopers o& anient /reee and omeG tose (o &irst s8))ested tat matter is made o& atomsG!emorit8s, Epi8r8s, and teir &ollo(ers =and .8reti8s, te &irst pop8larier o& siene< sandalo8sl proposed man (orlds and man alien li&e &orms, all made o& te same kinds o& atoms as (e$ e o&&ered &or o8r onsideration in&inities in spae and time$ B8t in te pre'ailin) anons o& te *est, se8lar and saerdotal, pa)an and +ristian, atomist ideas (ere re'iled$ Instead, te ea'ens (ere not at all like o8r (orld$ e (ere 8nalterable and per&et$ e Eart (as m8table and orr8pt$ e oman statesman and pilosoper +iero s8mmaried te ommon 'ie(: In te ea'ens $ $ $ tere is notin) o& ane or aard, no error, no &r8stration, b8t absol8te order, a8ra, al8lation and re)8larit$ ilosop and reli)ion a8tioned tat te )ods =or /od< (ere &ar more po(er&8l tan (e, Healo8s o& teir prero)ati'es and K8ik to mete o8t H8stie &or ins8&&erable arro)ane$ t te same time, tese disiplines ad not a l8e tat teir o(n teain) o& o( te ni'erse is ordered (as a oneit and a del8sion$ ilosop and reli)ion presented mere opinionGopinion tat mi)t be o'ert8rned b obser'ation and eCperimentGas ertaint$ is (orried tem not at all$ at some o& teir deepl eld belie&s mi)t t8rn o8t to be mistakes (as a possibilit ardl onsidered$ !otrinal 8milit
16
(as to be pratied b oters$ eir o(n teain)s (ere inerrant and In&allible$ In tr8t, te ad better reason to be 8mble tan te kne($ BEGINNING WITH COPERNICUSin
te middle siCteent ent8r, te iss8e (as &ormall Hoined$ e pit8re o& te S8n rater tan te Eart at te enter o& te ni'erse (as 8nderstood to be dan)ero8s$ 2bli)in)l, man solars (ere K8ik to ass8re te reli)io8s ierar tat tis ne(&an)led potesis represented no serio8s allen)e to on'entional (isdom$ In a kind o& split-brain ompromise, te S8n-entered sstem (as treated as a mere omp8tational on'eniene, not an astronomial realit tat is, te Eart (as reall at te enter o& te ni'erse, as e'erbod kne(? b8t i& o8 (ised to predit (ere >8piter (o8ld be on te seond 8esda o& No'ember te ear a&ter neCt, o8 (ere permitted to pretend tat te S8n (as at te enter$ en o8 o8ld al8late a(a and not a&&ront te 8torities$1 is as no dan)er in it, (rote obert +ardinal Bellarmine, te &oremost #atian teolo)ian in te earl se'enteent ent8r, and s8&&ies &or te matematiians$ B8t, to a&&irm tat te S8n is reall &iCed in te enter o& te ea'ens and tat te Eart re'ol'es 'er s(i&tl aro8nd te S8n is a dan)ero8s tin), not onl irritatin) te teolo)ians and pilosopers, b8t inH8rin) o8r ol &ait and makin) te sared sript8re &alse$ %reedom o& belie& is perniio8s, Bellarmine (rote on anoter oasion$ It is notin) b8t te &reedom to be (ron)$ Besides, i& te Eart (as )oin) aro8nd te S8n, nearb stars so8ld seem to mo'e a)ainst te bak)ro8nd o& more distant stars as, e'er siC monts, (e si&t o8r perspeti'e &rom one side o& te EartAs orbit to te oter$ No s8 ann8al parallaC ad been &o8nd$ e +opernians ar)8ed tat tis (as bea8se te stars (ere eCtremel &ar a(aGmabe a million times more distant tan te Eart is &rom te S8n$ eraps better telesopes, in &8t8re times, (o8ld &ind an ann8al parallaC$ e )eoentrists onsidered tis a desperate attempt to sa'e a &la(ed potesis, and l8diro8s on te &ae o& it$ *en /alileo t8rned te &irst astronomial telesope to te sk, te tide be)an to t8rn$ e diso'ered tat >8piter ad a little retin8e o& moons irlin) it, te inner ones orbitin) &aster tan te o8ter ones, H8st as +operni8s ad ded8ed &or te motion o& te planets abo8t te S8n$ e &o8nd tat er8r and #en8s (ent tro8) pases like te oon =so(in) te orbited te S8n<$ oreo'er, te ratered oon and te spotted S8n allen)ed te per&etion o& te ea'ens$ is ma in part onstit8te te sort o& tro8ble ert8llian (as (orried abo8t tirteen 8ndred ears earlier, (en e pleaded, I& o8 a'e an sense or modest, a'e done (it prin) into te re)ions o& te sk, into te destin and serets o& te 8ni'erse$
1
+operni8sA &amo8s book (as &irst p8blised (it an introd8tion b te teolo)ian ndre( 2siander, inserted (ito8t te kno(led)e o& te din) astronomer$ 2sianderAs (ell-meanin) attempt to reonile reli)ion and +opernian astronom ended (it tese (ords: Q.Ret no one eCpet antin) in te (a o& ertaint o& astronom, sine astronom an o&&er 8s notin) ertain, lest, i& anone take as tr8e tat (i as been onstr8ted &or $moter 8se, e )o a(a &rom tis disipline a bi))er &ool tan ( en e ane to it$ +ertaint o8ld be &o8nd onl in reli)ion$
17
In ontrast, /alileo ta8)t tat (e an interro)ate Nat8re b obser'ation and eCperiment$ en, &ats (i at &irst si)t seem improbable (ill, e'en on sant eCplanation, drop te loak (i ad idden tem and stand &ort in naked and simple bea8t$ re not tese &ats, a'ailable e'en &or skeptis to on&irm, a s8rer insi)t into /odAs ni'erse tan all te spe8lations o& te teolo)iansD B8t (at i& tese &ats ontradit te belie&s o& tose (o old teir reli)ion inapable o& makin) mistakesD e prines o& te +8r treatened te a)ed astronomer (it tort8re i& e persisted in teain) te abominable dotrine tat te Eart mo'ed$ e (as sentened to a kind o& o8se arrest &or te remainder o& is li&e$ )eneration or t(o later, b te time Isaa Ne(ton demonstrated tat simple and ele)ant psis o8ld K8antitati'el eCplainGand preditGall te obser'ed l8nar and planetar motions =pro'ided o8 ass8med te S8n at te enter o& te Solar Sstem<, te )eoentrist oneit eroded &8rter$ In 17"5, in an attempt to diso'er stellar parallaC, te painstakin) En)lis amate8r astronomer >ames Bradle st8mbled on te aberration o& li)t$ e term aberration, I s8ppose, on'es sometin) o& te 8neCpetedness o& te diso'er$ *en obser'ed o'er te o8rse o& a ear, stars (ere &o8nd to trae little ellipses a)ainst te sk$ B8t all te stars (ere &o8nd to do so$ is o8ld not be stellar parallaC, (ere (e (o8ld eCpet a bi) parallaC &or nearb stars and an indetetible one &or &ara(a stars$ Instead, aberration is similar to o( raindrop &allin) diretl do(n on a speedin) a8to seem to te passen)er, to be &allin) at a slant? te &aster te ar )oes, te steeper te slant$ I& te Eart (ere stationar at te enter o& te ni'erse$ and not speedin) in its orbit aro8nd te S8n, Bradle (o8ld nor a'e &o8nd te aberration o& li)t$ It (as a ompellin) demonstration tat te Eart re'ol'ed abo8t te S8n$ It on'ined most astronomers and some oters b8t not, Bradle to8)t, te nti-+opernians$ B8t not 8ntil 1;37 did diret obser'ations o& te stars pro'e in te learest (a tat te Eart is indeed irlin) te S8n$ e lon)-debated ann8al parallaC (as at last diso'eredGnot b better ar)8ments, b8t b better instr8ments$ Bea8se eCplainin) (at it means is m8 more strai)t&or(ard tan eCplainin) te aberration o& li)t, its diso'er (as 'er important$ It po8nded te &inal nail into te o&&in o& )eoentrism$ o8 need onl look at o8r &in)er (it o8r le&t ee and ten (it o8r ri)t and see it seem to mo'e$ E'erone an 8nderstand parallaC$ B te nineteent ent8r, all sienti&i )eoentrists ad been on'erted or rendered eCtint$ 2ne most sientists ad been on'ined, in&ormed p8bli opinion ad s(i&tl an)ed, in some o8ntries in a mere tree or &o8r )enerations$ 2& o8rse, in te time o& /alileo and Ne(ton and e'en m8 later, tere (ere still some (o obHeted, (o tried to pre'ent te ne( S8n-entered ni'erse &rom beomin) aepted, or e'en kno(n$ nd tere (ere man (o at least arbored seret reser'ations$ B te late t(entiet ent8r, H8st in ase tere (ere an oldo8ts, (e a'e been able to settle te matter diretl$ *eA'e been able to test (eter (e li'e in an Eart-entered sstem (it planets a&&iCed to transparent rstal speres, or in a S8n-entered sstem (it planets ontrolled at a distane b te )ra'it o& te S8n$ *e a'e, &or eCample, probed te planets (it radar$ *en (e bo8ne a si)nal o&& a moon o& Sat8rn, (e reei'e no radio eo &rom a nearer rstal spere attaed to >8piter$ 28r spaera&t arri'e at teir appointed destinations (it astonisin) preision, eCatl as predited b Ne(tonian )ra'itation$ *en o8r sips &l to ars,
1;
sa, teir instr8ments do not ear a tinklin) so8nd or detet sards o& broken rstal as te ras tro8) te speres tatGaordin) to te a8toritati'e opinions tat pre'ailed &or millenniaG propel #en8s or te S8n ill teir d8ti&8l motions abo8t te entral Eart$ *en Vo$ager 1 sanned te Solar Sstem &rom beond te o8termost planet, it sa(, H8st as +operni8s and /alileo ad said (e (o8ld, te S8n in te middle and te planets in onentri orbits abo8t it$ %ar &rom bein) te enter o& te ni'erse, te Eart is H8st one o& te orbitin) dots$ No lon)er on&ined to a sin)le (orld, (e are no( able to rea o8t to oters and determine deisi'el (at kind o& planetar sstem (e inabit$ EVERY OTHER PROPOSAL , and
teir n8mber is le)ion, to displae 8s &rom osmi enter sta)e as also been resisted, in part &or similar reasons$ *e seem to ra'e pri'ile)e, merited not b o8r (ork, b8t b o8r birt, b te mere &at tat, sa, (e are 8mans and born on Eart$ *e mi)t all it te antropoentriGte 8man-enteredGoneit$ is oneit is bro8)t lose to 8lmination in te notion tat (e are reated in /odAs ima)e: e +reator and 8ler o& te entire ni'erse looks H8st like me$ , (at a oinidene o( on'enient and satis&in)F e siCt-ent8r-B$+$ /reen pilosoper enopanes 8nderstood te arro)ane o& te perspeti'e: e Etiopians make teir )ods blak and sn8b-nosed? te raians sa teirs a'e bl8e ees and red air $ $ $ es, and i& oCen and orses or lions ad ands, and o8ld paint (it teir ands, and prod8e (orks o& art as men do, orses (o8ld paint te &orms o& te )ods like orses, and oCen like oCen $ $ $ S8 attit8des (ere one desribed as pro'inialGte nai'e eCpetation tat te politial ieraries and soial on'entions o& an obs8re pro'ine eCtend to a 'ast empire omposed o& man di&&erent traditions and 8lt8res? tat te &amiliar boondoks, our boondoks, are te enter o& te (orld$ e o8ntr b8mpkins kno( almost notin) abo8t (at else is possible$ e &ail to )rasp te insi)ni&iane o& teir pro'ine or te di'ersit o& te Empire$ *it ease, te appl teir o(n standards and 8stoms to te rest o& te planet$ B8t plopped do(n in #ienna, sa, or amb8r), or Ne( ork, r8e&8ll te reo)nie o( limited teir perspeti'e as been$ e beome depro'inialied$ odern siene as been a 'oa)e into te 8nkno(n, (it a lesson in 8milit (aitin) at e'er stop$ an passen)ers (o8ld rater a'e staed ome $
19
+
E
3
E /E !E2I2NS Q2ne pilosoperR asserted tat e kne( te (ole seret $ $ $ QRe s8r'eed te t(o elestial stran)ers &rom top to toe, and maintained to teir &aes tat teir persons, teir (orlds, teir s8ns, and teir stars, (ere reated solel &or te 8se o& man$ t tis assertion o8r t(o tra'elers let temsel'es &all a)ainst ea oter, seied (it a &it o& $ $ $ ineCtin)8isable la8)ter$ --#2.IE,M!#OME%AS3 A P!&OSOP!#A& !S/O, (1*52)
In te se'enteent ent8r tere (as still some ope tat, e'en i& te Eart (as not te enter o& te ni'erse, it mi)t be te onl (orld$ B8t /alileoAs telesope re'ealed tat te oon ertainl does not possess a smoot and polised s8r&ae and tat oter (orlds mi)t look H8st like te &ae o& te Eart itsel&$ e oon and te planets so(ed 8nmistakabl tat te ad as m8 laim to bein) (orlds as te Eart doesG(it mo8ntains, raters, atmosperes, polar ie aps, lo8ds, and, in te ase o& Sat8rn, a dalin), 8neard-o& set o& ir8m&erential rin)s$ &ter millennia o& pilosopial debate, te iss8e (as settled deisi'el in &a'or o& te pl8ralit o& (orlds$ e mi)t be pro&o8ndl di&&erent &rom o8r plane t$ None o& tem mi)t be as on)enial &or li&e$ B8t te Eart (as ardl te onl one$ is (as te neCt in te series o& /reat !emotions, do(nli&tin) eCperienes, demonstrations o& o8r apparent insi)ni&iane, (o8nds tat siene as, in its sear &or /alileoAs &ats, deli'ered to 8man pride$ WELL, SOME HOPED
, e4en i "e Ear" in" a" "e 7en"er o "e ni4ere "e Sun i3 /e Sun i our Sun3 So "e Ear" i approxima"el$ a" "e 7en"er o "e ni4ere $ eraps some o& o8r pride o8ld in tis (a be sal'a)ed$ B8t b te nineteent ent8r, obser'ational astronom ad made it lear tat te S8n is b8t one lonel star in a )reat sel&-)ra'itatin) assembla)e o& s8ns alled te ilk *a /alaC$ %ar &rom bein) at te enter o& te /alaC, o8r S8n (it its ento8ra)e o& dim and tin planets lies in an 8ndistin)8ised setor o& an obs8re spiral arm$ *e are tirt to8sand li)t ears &rom te +enter$ :ell our Milk$ :a$ i "e onl$ galax$$ e ilk *a /alaC is one o& billions, peraps 8ndreds o& billions o& )alaCies notable neiter in mass nor in bri)tness nor in o( its stars are on&i)8red and arraed$ Some modern deep sk poto)raps so( more )alaCies beond te ilk *a tan stars (itin te ilk *a$ E'er one o& tem is an island 8ni'erse ontainin) peraps a 8ndred billion s8ns$ S8 an ima)e is a pro&o8nd sermon on 8milit$
"0
:ell "en a" lea" our %alax$ i a" "e 7en"er o "e ni4ere $ No, tis is (ron) too$ *en te eCpansion o& te ni'erse (as &irst diso'ered, man people nat8rall )ra'itated to te notion tat te ilk *a (as at te enter o& te eCpansion, and all te oter )alaCies r8nnin) a(a &rom 8s$ *e no( reo)nie tat astronomers on an )alaC (o8ld see all te oters r8nnin) a(a $ &rom tem? 8nless te (ere 'er are&8l, te (o8ld all onl8de tat te (ere at te enter o& te ni'erse$ ere is, in &at, no enter to te eCpansion, no point o& ori)in o& te Bi) Ban), at least not in ordinar tree-dimensional spae$ :ell e4en i "ere are unre o ;illion o galaxie ea7
8piter, orbitin) te nearest star, lpa +enta8ri, (o8ld still be di&&i8lt to detet$ Iii o8r i)norane, te )eoentrists &ind ope$ ere (as one a sienti&i potesisGnot H8st (ell reei'ed b8t pre'ailin)Gtat s8pposed o8r solar sstem to a'e &ormed tro8) te near ollision o& te anient S8n (it anoter star? te )ra'itational tidal interation p8lled o8t tendrils o& s8nst8&& tat K8ikl ondensed into planets$ Sine spae is mainl empt and near stellar ollisions most rare, it (as onl8ded tat &e( oter planetar sstems eCistGperaps onl one, aro8nd tat oter star tat lon) a)o o-parented te (orlds o& o8r solar sstem$ Earl in m st8dies, I (as amaed and disappointed tat s8 a 'ie( ad e'er been taken serio8sl, tat &or planets o& oter stars, absene o& e'idene ad been onsidered e'idene o& absene$ oda (e a'e &irm e'idene &or at least tree planets orbitin) an eCtremel dense star, te p8lsar desi)nated B1"571", abo8t (i IAll sa more later$ nd (eA'e &o8nd, &or more tan al& te stars (it masses like te S8nAs, tat earl in teir areers teAre s8rro8nded b )reat disks o& )as aid d8st o8t o& (i planets seem to &orm$ 2ter planetar sstems no( look to be a osmi ommonplae, mabe e'en (orlds sometin) like te Eart$ *e so8ld be able, in te neCt &e( deades, to in'entor at least te lar)er planets, i& te eCist, o& 8ndreds o& nearb stars$ :ell i our poi"ion in pa7e oen" re4eal our pe7ial role our poi"ion in "ime oe= :e4e ;een in "e ni4ere in7e /e >eginning =)i'e or take a &e( das<$ :e4e ;een gi4en pe7ial reponi;ili"ie ;$ "e #rea"or$ It one seemed 'er reasonable to tink o& te ni'erse as be)innin) H8st a little be&ore o8r olleti'e memor is obs8red b te passa)e o& time and te illitera o& o8r anestors$ /enerall speakin), tatAs 8ndreds or to8sands o& ears a)o$ eli)ions tat p8rport to desribe te ori)in o& te ni'erse o&ten spei&Gimpliitl or eCpliitlGa date o& ori)in o& ro8)l s8 'inta)e, a birtda &or te (orld$ I& o8 add 8p all te be)ats in /enesis, &or eCample, o8 )et an a)e &or te Eart: 6,000 ears old, pl8s or min8s a little$ e 8ni'erse is said to be eCatl as old as te Eart$ is is still te standard o& >e(is, +ristian, and oslem &8ndamentalists and is learl re&leted in te >e(is alendar$ B8t so o8n) a ni'erse raises an a(k(ard K8estion: o( is it tat tere are astronomial obHets more tan 6,000 li)t-ears a(aD It takes li)t a ear to tra'el a li)t-ear, 10,000 ears to tra'el 10,000 li)t-ears, and so on$ *en (e look at te enter o& te ilk *a /alaC, te li)t (e see le&t its so8re 30,000 ears a)o$ e nearest spiral )alaC like o8r
"1
o(n, 31 in te onstellation ndromeda, is " million li)t-ears a(a, so (e are seein) it as it (as (en te li)t &rom it set o8t on its lon) Ho8rne to EartG" million ears a)o$ nd (en (e obser'e distant K8asars 5 billion li)t-ears a(a, (e are seein) tem as te (ere 5 billion ears a)o, be&ore te Eart (as &ormed$ =e are, almost ertainl, 'er di&&erent toda$< I&, despite tis, (e (ere to aept te literal tr8t o& s8 reli)io8s books, o( o8ld (e reonile te dataD e onl pla8sible onl8sion, I tink, is tat /od reentl made all te potons o& li)t arri'in) on te Eart in s8 a oerent &ormat as to mislead )enerations o& astronomers into te misappreension tat tere are s8 tin)s as )alaCies and K8asars, and intentionall dri'in) tem to te sp8rio8s onl8sion tat te ni'erse is 'ast and old$ is is s8 a male'olent teolo) I still a'e di&&i8lt belie'in) tat anone, no matter o( de'oted to te di'ine inspiration o& an reli)io8s book, o8ld serio8sl entertain it$ Beond tis, te radioati'e datin) o& roks, te ab8ndane o& impat raters on man (orlds, te e'ol8tion o& te stars, and te eCpansion o& te ni'erse ea pro'ides ompellin) and independent e'idene tat o8r ni'erse is man billions o& ears oldGdespite te on&ident assertions o& re'ered teolo)ians tat a (orld so old diretl ontradits te (ord o& /od, and tat at an rate in&ormation on te antiK8it o& te (orld is inaessible eCept to &ait$ 1 ese lines o& e'idene, as (ell, (o8ld a'e to be man8&at8red b a deepti'e and maliio8s deitG 8nless te (orld is m8 older tan te literalists in te >8deo-+ristian-Islami reli)ion s8ppose$ 2& o8rse, no s8 problem arises &or tose man reli)io8s people (o treat te Bible and te T8rAan as istorial and moral )8ides and )reat literat8re, b8t (o reo)nie tat te perspeti'e o& tese sript8res on te nat8ral (orld re&lets te r8dimentar siene o& te time in (i te (ere (ritten$ )es rolled b be&ore te Eart be)an$ ore a)es (ill r8n teir o8rse be&ore it is destroed$ distintion needs to be dra(n bet(een o( old te Eart is =aro8nd 4$5 billion ears< and o( old te ni'erse is =abo8t 15 billion ears sine te Bi) Ban)<$ e immense inter'al o& time bet(een te ori)in o& te ni'erse and o8r epo (as t(o-tirds o'er be&ore te Eart ame to be$ Some stars and planetar sstems are billions o& ears o8n)er, oters billions o& ears older$ B8t in /enesis, apter 1, 'erse 1, te ni'erse and te Eart are reated on te same da$ e ind8-B8ddist->ain reli)ion tends not to on&o8nd te t(o e'ents$ s &or 8mans, (eAre lateomers$ *e appear in te last instant o& osmi time$ e istor o& te ni'erse till no( (as 99$99; perent o'er be&ore o8r speies arri'ed on te sene$ In tat 'ast s(eep o& aeons, (e o8ld not a'e ass8med an speial responsibilities &or o8r planet, or li&e, or antin) else$ *e (ere not ere$ :ell i
St$ 8)8stine, in e +it o& /od, sas, s it is not et siC to8sand ears sine te &irst man $ $ $ are not tose to be ridi8led rater tan re&8ted (o tr to pers8ade 8s o& antin) re)ardin) a spae o& time so di&&erent &rom, and ontrar to, te asertained tr8tD $ $ $ *e, bein) s8stained b di'ine a8torit in te istor o& o8r reli)ion, a'e no do8bt tat (ate'er is opposed to it is most &alse$ e eCoriates te anient E)ptian tradition tat te (orld is at m8 as a 8ndred to8sand ears old as abominable lies$ St$ omas K8inas, in te S8mma eolo)ia, &latl states tat te ne(ness o& te (orld annot be demonstrated &rom te (orld itsel&$ e (ere so s8re$
""
im tat te la(s o& Nat8re m8st be te same no matter (at te 'eloit or &rame o& re&erene o& te obser'er$ *it tis as is startin) point, e de'eloped te Speial eor o& elati'it$ Its onseK8enes are biarre, o8nter int8iti'e, and )rossl ontradit ommon senseGb8t onl at 'er i) speeds$ +are&8l and repeated obser'ations so( tat is H8stl elebrated teor is an a8rate desription o& o( te (orld is made$ 28r ommonsense int8itions an be mistaken$ 28r pre&erenes donAt o8nt$ *e do not li'e in a pri'ile)ed re&erene &rame$ 2ne onseK8ene o& speial relati'it is time dilationGte slo(in) do(n o& time as te obser'er approaes li)t speed$ o8 an still &ind laims tat time dilation applies to (ates and elementar partilesGand, pres8mabl, to iradian and oter rtms in plants, animals, and mirobesGb8t not to 8man biolo)ial loks$ 28r speies as been )ranted, it is s8))ested, speial imm8nit &rom te la(s o& Nat8re, (i m8st aordin)l be able to distin)8is deser'in) &rom 8ndeser'in) olletions o& matter$ =In &at, te proo& Einstein )a'e &or speial, relati'it admits no s8 distintions$< e idea o& 8mans as eCeptions to relati'it seems anoter inarnation o& te notion o& speial reation: :ell e4en i our poi"ion our epo7 our mo"ion an our
sel&-on)rat8lator a8'inisms are allen)ed in et anoter arena o& sienti&i debateGin tis ent8r, &or eCample, in attempts to 8nderstand te nat8re o& 8man seC8alit, te eCistene o& te 8nonsio8s mind, and te &at tat man psiatri illnesses and arater de&ets a'e a mole8lar ori)in$ B8t also: :ell e4en i
"3
names$ !olls, n8trakers, 8ps, and sa8ers dane and a'e opinions$ e dis r8ns a(a (it te spoon$ In te omas te ank En)ine series, (e e'en a'e antropomorpi loomoti'es and rail(a ars, armin)l portraed$ No matter (at (eAre tinkin) abo8t, animate or inanimate, (e tend to in'est it (it 8man traits$ *e anAt elp o8rsel'es$ e ima)es ome readil to mind$ +ildren are learl &ond o& tem$ *en (e talk abo8t a treatenin) sk, a tro8bled sea diamonds resistin) bein) srated, te Eart attratin) passin) asteroid, or an atom bein) eCited, (e are a)ain dra(n to a kind o& animist (orld'ie($ *e rei&$ Some anient le'el o& o8r tinkin) endo(s inanimate Nat8re (it li&e, passions, and &oreto8)t$ e notion tat te Eart is sel&-a(are as latel been )ro(in) at te &rin)es o& te /aia potesis$ B8t tis (as ommonplae belie& o& bot te anient /reeks and te earl +ristians$ 2ri)en (ondered (eter te eart also, aordin) to its o(n nat8re, is ao8ntable &or some sin$ ost o& anient solars to8)t te stars ali'e$ is (as also te position o& 2ri)en, o& St$ mbrose =te mentor o& St$ 8)8stine<, and e'en, in a more K8ali&ied &orm, o& St$ omas K8inas$ e Stoi pilosopial position on te S8nAs nat8re (as stated b +iero, in te &irst ent8r B$+$: Sine te S8n resembles tose &ires (i are ontained in te bodies o& li'in) reat8res, te S8n m8st also be ali'e$ nimist attit8des in )eneral seem to a'e been spreadin) reentl$ In a 1954 merian s8r'e, 75 perent o& people polled (ere (illin) to state tat te S8n is not ali'e? in 19;9, onl 30 perent (o8ld s8pport so ras a proposition$ 2n (eter an a8tomobile tire an &eel antin), 90 perent o& respondents denied it emotions in 1954, b8t onl 73 perent in 19;9$ *e an reo)nie ere a sortomin)Gin some ir8mstanes serio8sGin o8r abilit to 8nderstand te (orld$ +arateristiall, (ill-nill, (e seem ompelled to proHet o8r o(n nat8re onto Nat8re$ lto8) tis ma res8lt in a onsistentl distorted 'ie( o& te (orld, it does a'e one )reat 'irt8eGproHetion is te essential preondition &or ompassion$ Oka$ ma$;e
"4
*at abo8t te related matter o& (eter (e are apable o& reatin) intelli)enes smarter tan o8rsel'esD +omp8ters ro8tinel do matematis tat no 8naided 8man an mana)e, o8tper&orm (orld ampions in ekers and )rand masters in ess, speak and 8nderstand En)lis and oter lan)8a)es, (rite presentable sort stories and m8sial ompositions, learn &rom teir mistakes, and ompetentl pilot sips, airplanes, and spaera&t$ eir abilities steadil impro'e$ eAre )ettin) smaller, &aster, and eaper$ Ea ear, te tide o& sienti&i ad'ane laps a little &8rter asore on te island o& 8man intellet8al 8niK8eness (it its embattled asta(as$ I&, at so earl a sta)e in o8r tenolo)ial e'ol8tion, (e a'e been able to )o so &ar in reatin) intelli)ene o8t o& silion and metal, (at (ill be possible in te &ollo(in) deades and ent8riesD *at appens (en smart maines are able to man8&at8re smarter mainesD
PERHAPS THE CLEAREST INDICATION tat
te sear &or an 8nmerited pri'ile)ed position &or 8mans (ill ne'er be (oll abandoned is (at in psis and astronom is alled te ntropi riniple$ It (o8ld be better named te ntropoentri riniple$ It omes in 'ario8s &orms$ e *eak ntropi riniple merel notes tat i& te la(s o& Nat8re and te psial onstantsG s8 as te speed o& li)t, te eletrial ar)e o& te eletron, te Ne(tonian )ra'itational onstant, or lankAs K8ant8m meanial onstant ad been di&&erent, te o8rse o& e'ents leadin) to te ori)in o& 8mans (o8ld ne'er a'e transpired$ nder oter la(s and onstants, atoms (o8ld not old to)eter, stars (o8ld e'ol'e too K8ikl to lea'e s8&&iient time &or li&e to e'ol'e on nearb planets, te emial elements o& (i li&e is made (o8ld ne'er a'e been )enerated, and so on$ !i&&erent la(s, no 8mans$ ere is no ontro'ers abo8t te *eak ntropi riniple: +an)e te la(s and onstants o& Nat8re, i& o8 o8ld, and a 'er di&&erent 8ni'erse ma emer)eGin man ases, a 8ni'erse inompatible (it li&e$ 1 e mere &at tat (e eCist implies =b8t does not impose< onstraints on te la(s o& Nat8re$ In ontrast, te 'ario8s Stron) ntropi riniples )o m8 &arter? some o& teir ad'oates ome lose to ded8in) tat te la(s o& Nat8re and te 'al8es o& te psial onstants (ere establised =donAt ask o( or b *om< so tat 8mans (o8ld e'ent8all ome to be$ lmost all o& te oter possible 8ni'erses, te sa, are inospitable$ In tis (a, te anient oneit tat te ni'erse (as made &or 8s is res8sitated$ o me it eoes !r$ an)loss in #oltaireAs#anie, on'ined tat tis (orld, (it all its imper&etions, is te best possible$ It so8nds like plain) m &irst and o& brid)e, (innin), "; kno(in) tat tere are 54 billion billion billion =5$4 10 < possible oter ands tat I (as eK8all likel to a'e been dealt $ $ $ and ten &oolisl onl8din) tat a )od o& brid)e eCists and &a'ors me, a )od (o arran)ed te ards and te s8&&le (it m 'itor &oreordained &rom e Be)innin)$ *e do not kno( o( man oter (innin) ands tere are in te osmi dek, o( man oter kinds o& 8ni'erses, la(s o& Nat8re, and psial onstants: tat o8ld also lead to li&e and Intelli)ene and peraps e'en del8sions o& sel&-importane$ Sine (e kno( neCt to notin)
1
28r 8ni'erse is almost inompatible (it li&eGor at least (at (e 8nderstand as neessar &or li&e: E'en i& e'er star in a 8ndred billion )alaCies ad an Eartlike planet, (ito8t eroi tenolo)ial meas8res li&e o8ld prosper in onl abo8t 10 -37 te 'ol8me o& te ni'erse$ %or larit, letAs (rite it o8t: onl 0$000 000 000 000 000 000 000 000 000 000 000 000 1 o& o8r 8ni'erse is ospitable to li&e$ irt-siC eroes be&ore te one$ e rest is old, radiation-riddled blak 'a88m$
"5
abo8t o( te ni'erse (as madeGor e'en i& it (as madeGitAs di&&i8lt to p8rs8e tese notions prod8ti'el$ #oltaire asked * is tere antin)D EinsteinAs &orm8lation (as to ask (eter /od ad an oie in reatin) te ni'erse$ B8t i& te ni'erse is in&initel oldGi& te Bi) Ban) some 15 billion ears a)o is onl te most reent 8sp in an in&inite series o& osmi ontrations and eCpansionsGten it (as ne'e r reated and te K8estion o& ( it is as it is is rendered meanin)less$ I&, on te oter and, te ni'erse as a &inite a)e, ( is it te (a it isD * (asnAt it )i'en a 'er di&&erent araterD *i la(s o& Nat8re )o (it (i otersD re tere metala(s spei&in) te onnetionsD +an (e possibl diso'er temD 2& all onei'able la(s o& )ra'it, sa, (i ones an eCist sim8ltaneo8sl (it (i onei'able la(s o& K8ant8m psis tat determine te 'er eCistene o& marosopi matterD re all la(s (e an tink o& possible, or is tere onl a restrited n8mber tat an someo( be bro8)t into eCisteneD +learl (e a'e not a )limmerin) o& o( to determine (i la(s o& Nat8re are possible and (i are not$ Nor do (e a'e more tan te most r8dimentar notion o& (at orrelations o& nat8ral la(s are permitted$ %or eCample, Ne(tonAs 8ni'ersal la( o& )ra'itation spei&ies tat te m8t8al )ra'itational &ore attratin) t(o bodies to(ards ea oter is in'ersel proportional to te sK8are o& o( &ar te are apart$ o8 mo'e t(ie as &ar &rom te enter o& te Eart and o8 (ei) a K8arter as m8? ten times &arter and o8 (ei) onl a 8ndredt o& o8r ordinar (ei)t? et$ It is tis in'erse sK8are la( tat permits te eCK8isite ir8lar and elliptial orbits o& planets aro8nd te S8n, and moons aro8nd te planetsGas (ell as te preision traHetories o& o8r interplanetar spaera&t$ I& r is te distane bet(een te enters o& t(o masses, (e sa tat te )ra'itational &ore 'aries as 1r"$ 4 B8t i& tis eCponent (ere di&&erentGi& te )ra'itational la( (ere 1 r , sa, rater tan " 1r Gten te orbits (o8ld not lose? o'er billions o& re'ol8tions, te planets (o8ld spiral in and be ons8med in te &ier depts o& te S8n, or spiral o8t and be lost to interstellar spae$ I& te ni'erse (ere onstr8ted (it an in'erse &o8rt po(er la( rater tan an in'erse sK8are la(, soon tere (o8ld be no planets &or li'in) bein)s to inabit$ So o& all te possible )ra'itational &ore la(s, ( are (e so l8k as to li'e in a 8ni'erse sportin) a la( onsistent (it li&eD %irst o& o8rse, (eAre so l8k, bea8se i& (e (erenAt, (e (o8ldnAt be ere to ask te K8estion$ It is no mster tat inK8isiti'e bein)s (o e'ol'e on planets an be &o8nd onl in 8ni'erses tat admit planets$ Seond, te in'erse sK8are la( is not is te onl one onsistent (it stabilit o'er billions o& ears$ n po(er la( less steep 3 "$99 tan 1r =1r or 1r, &or eCample< (ill keep a planet in te 4i7ini"$ o& a ir8lar orbit e'en i& itAs )i'en a so'e$ *e a'e a tenden to o'erlook te possibilit tat oter onei'able la(s o& Nat8re mi)t also be onsistent (it li&e$ B8t tereAs a &8rter point: ItAs not arbitrar tat (e a'e an in'erse sK8are la( o& )ra'itation$ *en Ne(tonAs teor is 8nderstood in terms o& te more enompassin) )eneral teor o& relati'it, (e reo)nie tat te eCponent o& te )ra'it la( is " bea8se te n8mber o& psial dimensions (e li'e in is 3$ ll )ra'it la(s arenAt a'ailable, &ree &or a +reatorAs oosin)$ E'en )i'en an in&inite n8mber o& tree-dimensional 8ni'erses &or some )reat )od to tinker (it, te
"6
)ra'it la( (o8ld al(as la'e to be te la( o& te in'erse sK8are$ Ne(tonian )ra'it, (e mi)t sa, is not a ontin)ent &aet o& o8r 8ni'erse, b8t a neessar one$ In )eneral relati'it, )ra'it is ue to te dimensionalit and 8r'at8re o& spae$ *en (e talk abo8t )ra'it (e are talkin) abo8t loal dimples in spae-time$ is is b no means ob'io8s and e'en a&&ronts ommonsense notions$ B8t (en eCamined deepl, te ideas o& )ra'it and mass are not separate matters, b8t rami&iations o& te 8nderlin) )eometr o& spae-time$ I (onder i& sometin) like tis doesnAt appl )enerall to all antropi poteses$ e la(s or psial onstants on (i o8r li'es depend t8rn o8t to be members o& a lass, peraps e'en a 'ast lass, o& oter la(s and oter ps ial onstantsGb8t some o& tese are also ompatible (it a kind o& li&e$ 2&ten (e do not =or annot< (ork tro8) (at tose oter 8ni'erses allo($ Beond tat, not e'er arbitrar oie o& a la( o& Nat8re or a psial onstant ma be a'ailable, e'en to a maker o& 8ni'erses$ 28r 8nderstandin) o& (i la(s o& Nat8re and (i psial onstants are 8p &or )rabs is &ra)mentar at best$ oreo'er, (e a'e no aess to an o& tose p8tati'e alternati'e 8ni'erses$ *e a'e no eCperimental metod b (i antropi poteses ma be tested$ E'en i& te eCistene o& s8 8ni'erses (ere to &ollo( &irml &rom (ell-establised teoriesGo& K8ant8m meanis or )ra'itation, saG(e o8ld not be s8re tat tere (erenAt better teories tat predit no alternati'e 8ni'erses$ ntil tat time omes, i& it e'er does, it seems to me premat8re to p8t &ait in te ntropi riniple as an ar)8ment &or 8man entralit or 8niK8eness$ %inall, e'en i& te ni'erse (ere in"en"ionall$ reated to allo( &or te emer)ene o& li&e or intelli)ene, oter bein)s ma eCist on o8ntless (orlds$ I& so, it (o8ld be old om&ort to antropoentrists tat (e inabit one o& te &e( 8ni'erses tat allo( li&e and intelli)ene$ ere is sometin) st8nnin)l narro( abo8t o( te ntropi riniple is prased$ es, onl ertain la(s and onstants o& nat8re are onsistent (it o8r kind o& li&e$ B8t essentiall te same la(s and onstants are reK8ired to make a rok$ So ( not talk abo8t a ni'erse desi)ned so roks o8ld one da ome to be, and stron) and (eak .iti riniplesD I& stones o8ld pilosopie, I ima)ine .iti riniples (o8ld be at te intellet8al &rontiers$ ere are osmolo)ial models bein) &orm8lated toda in (i e'en te entire ni'erse is notin) speial$ ndrei .inde, &ormerl o& te .ebede' sial Instit8te in oso( and no( at Stan&ord ni'ersit, as inorporated 8rrent 8nderstandin) o& te stron) and (eak n8lear &ores and K8ant8m psis into a ne( osmolo)ial model$ .inde en'isions a 'ast +osmos, m8 lar)er tan o8r ni'erseGperaps eCtendin) to in&init bot in spae and timeGnot te paltr 15 billion li)t-ears or so in radi8s and 15 billion ears in a)e (i are te 8s8al 8nderstandin)$ In tis +osmos tere is, as ere, a kind o& K8ant8m &l8&& in (i tin str8t8resG m8 smaller tan an eletronGare e'er(ere &ormin), resapin), and dissipatin)? in (i, as ere, &l8t8ations in absol8tel empt spae reate pairs o& elementar partilesGan eletron and a positron, &or eCample$ In te &rot o& K8ant8m b8bbles, te 'ast maHorit remain s8bmirosopi$ B8t a tin &ration in&late, )ro(, and aie'e respetable 8ni'erseood$ e are so &ar a(a &rom 8s, to8)Gm8 &arter tan te 15 billion li)t-ears tat is te on'entional sale o& o8r 8ni'erseGtat, i& te eCist, te appear to be (oll inaessible and 8ndetetable$ ost o& tese oter 8ni'erses rea a maCim8m sie and ten ollapse, ontrat to a point, and disappear &ore'er$ 2ters ma osillate$ Still oters ma eCpand (ito8t limit$ In
"7
di&&erent 8ni'erses tere (ill be di&&erent la(s o& nat8re$ *e li'e, .inde ar)8es, in one s8 8ni'erseGone in (i te psis is on)enial &or )ro(t, in&lation, eCpansion, )alaCies, stars, (orlds, li&e$ *e ima)ine o8r 8ni'erse to be 8niK8e, b8t it is one o& an immense n8mberGperaps an in&inite n8mberGo& eK8all 'alid, eK8all independent, eK8all isolated 8ni'erses$ ere (ill be li&e in some, and not in oters$ In tis 'ie( te obser'able ni'erse is H8st a ne(l &ormed bak(ater o& a m8 'aster, in&initel old, and (oll 8nobser'able +osmos$ I& sometin) like tis is ri)t, e'en o8r resid8al pride, pallid as it m8st be, o& li'in) in te onl 8ni'erse is denied to 8s$1 abe someda, despite 8rrent e'idene, a means (ill be de'ised to peer into adHaent 8ni'erses, sportin) 'er di&&erent la(s o& nat8re, and (e (ill see (at else is possible$ 2r peraps inabitants o& adHaent 8ni'erses an peer into o8rs$ 2& o8rse, in s8 spe8lations (e a'e &ar eCeeded te bo8nds o& kno(led)e$ B8t i& sometin) like .indeAs +osmos is tr8e, tere isG amain)lGstill anoter de'astatin) depro'inialiation a(aitin) 8s$ 28r po(ers are &ar &rom adeK8ate to be reatin) 8ni'erses antime soon$ Stron) ntropi riniple ideas are not amenable to proo& =alto8) .indeAs osmolo) does a'e some testable &eat8res<$ ECtraterrestrial li&e aside, i& sel&-on)rat8lator pretensions to entralit a'e no( retreated to s8 bastions imper'io8s to eCperiment, ten te seK8ene o& sienti&i battles (it 8man a8'inism (o8ld seem to a'e been, at least lar)el, (on$ THE LONG-STANDING VIEW , as
s8mmaried b te pilosoper Imman8el ant, tat (ito8t man $ $ $ te (ole o& reation (o8ld be a mere (ilderness, a tin) in 'ain, and a'e no &inal end is re'ealed to be sel&-ind8l)ent &oll$ riniple o& ediorit seems to appl to all o8r ir8mstanes$ *e o8ld not a'e kno(n be&oreand tat te e'idene (o8ld be, so repeatedl and toro8)l, inompatible (it te proposition tat 8man bein)s are at enter sta)e in te ni'erse$ B8t most o& te debates a'e no( been settled deisi'el in &a'or o& a position tat, o(e'er pain&8l, an be enaps8lated in a sin)le sentene: *e a'e not been )i'en te lead in te osmi drama$ eraps someone else as$ eraps no one else as$ In eiter ase, (e a'e )ood reason &or 8milit$
1
%or s8 ideas, (ords tend to &ail 8s$ /erman lo8tion &or ni'erse is Qdad 911(i makes te inl8si'eness K8ite 8nmistakable$ *e mi)t sa tat o8r 8ni'erse is b8t one in a 8lti'erse, b8t I pre&er to 8se +osmos &or e'ertin) and ni'erse &or te onl one (e an kno( abo8t$
";
+
E
4
NI#ESE N2 !E %2 S e Sea o& %ait *as one, too, at te &8ll, and ro8nd eartAs sore .a like te &olds o& a bri)t )irdle &8rlAd$ B8t no( I onl ear Its melanol, lon), (itdra(in) roar, etreatin), to te breat 2& te ni)t-(ind, do(n te 'ast ed)es drear nd naked sin)les o& te (orld$ GE* N2.!, !2#E BE+ =1;67<
Wat a bea8ti&8l s8nset, (e sa, or IAm 8p be&ore s8nrise$ No matter (at te sientists alle)e, in e'erda spee (e o&ten i)nore teir &indin)s$ *e donAt talk abo8t te Eart t8rnin), b8t abo8t te S8n risin) and settin)$ r &orm8latin) it in +opernian lan)8a)e$ *o8ld o8 sa, Bill, be ome b te time te Eart as rotated eno8) so as to o8lt te S8n belo( te loal orionD Bill (o8ld be lon) )one be&ore o8Are &inised$ We a'enAt been able e'en to &ind a )rae&8l lo8tion tat a8ratel te elioentri insi)t$ *e at te enter and e'ertin) else irlin) 8s is b8ilt into o8r lan)8a)es? (e tea it to o8r ildren$ *e are 8nreonstr8ted )eoentrists idin) beind a +opernian 'eneer$1 In 1633 te oman +atoli +8r ondemned /alileo &or teain) tat te Eart )oes aro8nd te S8n$ .etAs take a loser look at tis &amo8s ontro'ers$ In te pre&ae to is book omparin) te t(o potesesGan Eart-entered and a S8n-entered 8ni'erseG/alileo ad (ritten, e elestial penomena (ill be eCamined, stren)tenin) te +opernian potesis 8ntil it mi)t seem tat tis m8st tri8mp absol8tel$
nd later in te book e on&essed, Nor an I e'er s8&&iientl admire Q+operni8s and is &ollo(ersR? te a'e tro8) seer &ore o& 1
2ne o& te &e( K8asi-+opernian eCpressions in En)lis is e ni'erse doesnAt re'ol'e aro8nd o8-an astronomial tr8t
intended to brin) &led)lin) narissists do(n to Eart$
"9
intellet done s8 'iolene to teir o(n senses as to pre&er (at reason told tem o'er (at sensible eCperiene plainl so(ed tem $ $ $
e +8r delared, in its inditment o& /alileo, e dotrine tat te eart is neiter te enter o& te 8ni'erse nor immo'able, b8t mo'es e'en (it a dail rotation, is abs8rd, and bot psolo)iall and teolo)iall &alse, and at te least an error o& &ait$
/alileo replied, e dotrine o& te mo'ements o& te eart and te &iCit o& te s8n is ondemned on te )ro8nd tat te Sript8res speak in man plaes o& te s8n mo'in) and te eart standin) still $ $ $ It is pio8sl spoken tat te Sript8res annot lie$ B8t none (ill den tat te are &reK8entl abstr8se and teir tr8e meanin) di&&i8lt to diso'er, and more tan te bare (ords si)ni&$ I tink tat in te dis8ssion o& nat8ral problems (e o8)t to be)in not (it te Sript8res, b8t (it eCperiments and demonstrations$
B8t in is reantation =>8ne "", 1633< /alileo (as made to sa,
a'in) been admonised b te ol 2&&ie entirel to abandon te &alse opinion tat te S8n (as te enter o& te 8ni'erse and immo'able, and tat te Eart (as not te enter o& te same and tat it mo'ed $ $ $ I a'e been $ $ $ s8speted o& eres, tat is, o& a'in) eld and belie'ed tat te S8n is te enter o& te 8ni'erse and immo'able, and tat te Eart is not te enter o& te same, and tat it does mo'e $ $ $ 1 abH8re (it a sinere eart and 8n&ei)ned &ait, I 8rse and detest te same errors and eresies, and )enerall all and e'er error and set ontrar to te ol +atoli +8r$
It took te +8r 8ntil 1;3" to remo'e /alileoAs (ork &rom its list o& books (i +atolis (ere &orbidden to read at te risk o& dire p8nisment o& teir immortal so8ls$ onti&ial disK8iet (it modern siene as ebbed and &lo(ed sine te time o& /alileo$ e i)-(ater mark in reent istor is te 1;64 Sllab8s o& Errors o& i8s I, te pope (o also on'ened te #atian +o8nil at (i te dotrine o& papal in&allibilit (as, at is insistene, &irst prolaimed$ ere are a &e( eCerpts: !i'ine re'elation is per&et and, tere&ore, it is not s8bHet to ontin8al and inde&inite pro)ress in order to orrespond (it te pro)ress o& 8man reason $ $ $ No man is &ree to embrae and pro&ess tat reli)ion (i e belie'es to be tr8e, )8ided b te li)t o& reason $ $ $ e +8r as po(er to de&ine do)matiall te reli)ion o& te +atoli +8r to be te onl tr8e reli)ion $ $ $ It is neessar e'en in te present da tat te +atoli reli)ion sall be eld as te onl reli)ion o& te state, to te eCl8sion o& all oter &orms o& (orsip $ $ $ e i'il libert o& e'er mode o& (orsip, and &8ll po(er )i'en to all o& openl and p8blil mani&estin) teir opinions and teir ideas ond8e more easil to orr8pt te morals and minds o& te people $ $ $ e oman onti&& annot and o8)t not to reonile imsel& or a)ree (it, pro)ress, liberalism and modern i'iliation$
30
o its redit, alto8) belatedl and rel8tantl, te +8r in 199" rep8diated its den8niation o& /alileo$ It still annot K8ite brin) itsel&, to8), to see te si)ni&iane o& its opposition$ In a 199" spee ope >on a8l II ar)8ed, %rom te be)innin) o& te )e o& Enli)tenment do(n to o8r o(n da, te /alileo ase as been a sort o& mt in (i te ima)e &abriated o8t o& te e'ents is K8ite &ar remo'ed &rom realit$ In tis perspeti'e, te /alileo ase (as a smbol o& te +atoli +8rAs s8pposed reHetion o& sienti&i pro)ress, or o& do)mati obs8rantism opposed to te &ree sear &or tr8t$
B8t s8rel te ol InK8isition 8serin) te elderl and in&irm /alileo in to inspet te instr8ments o& tort8re in te d8n)eons o& te +8r not onl admits b8t reK8ires H8st s8 an interpretation$ is (as not mere sienti&i a8tion and restraint, a rel8tane to si&t a paradi)m 8ntil ompellin) e'idene, s8 as te ann8al parallaC, (as a'ailable$ is (as &ear o& dis8ssion and debate$ +ensorin) alternati'e 'ie(s and treatenin) to tort8re teir proponents betra a lak o& &ait in te 'er dotrine and parisioners tat are ostensibl bein) proteted$ * (ere treats and /alileoAs o8se arrest neededD +annot tr8t de&end itsel& in its on&rontation (it errorD e ope does, to8), )o on to add: e error o& te teolo)ians o& te time, (en te maintained te entralit o& te eart, (as to tink tat o8r 8nderstandin) o& te psial (orldAs str8t8re (as in soiree (a imposed b te literal sense o& Sared Sript8res$
ere indeed onsiderable pro)ress as been madeGalto8) proponents o& &8ndamentalist &aits (ill be distressed to ear &rom te onti&& tat Sared Sript8re is not al(as literall tr8e$ B8t i& te Bible is not e'er(ere literall tr8e, (i parts are di'inel inspired and (i are merel &allible and 8manD s soon as (e admit tat tere are sript8ral mistakes =or onessions to te i)norane o& te times<, ten o( an te Bible be an inerrant )8ide to etis and moralsD i)t sets and indi'id8als no( aept as a8tenti te parts o& te Bible te like, and reHet tose tat are inon'enient or b8rdensomeD roibitions a)ainst m8rder, sa, are essential &or a soiet to &8ntion, b8t i& di'ine retrib8tion &or m8rder is onsidered impla8sible, (onAt more people tink te an )et a(a (it itD an &elt tat +operni8s and /alileo (ere 8p to no )ood and erosi'e o& te soial order$ Indeed an allen)e &rom an so8re, to te literal tr8t o& te Bible mi)t a'e s8 onseK8enes$ *e an readil see o( siene be)an to make people ner'o8s$ Instead o& ritiiin) tose (o perpet8ated te mts, p8bli ranor (as direted at tose (o disredited tem$ OUR ANCESTORS UNDERSTOODori)ins
b eCtrapolatin) &rom teir o(n eCperiene$ o( else o8ld te a'e done itD So te ni'erse (as ated &rom a osmi e)), or onei'ed in te
31
seC8al on)ress o& a moter )od and a &ater )od, or (as a kind o& prod8t o& te +reatorAs (orksopGperaps te latest o& man &la(ed attempts$ nd te ni'erse (as not m8 bi))er tan (e see, and not m8 older tan o8r (ritten or oral reords, and no(ere 'er di&&erent &rom plaes tat (e kno($ *eA'e tended in o8r osmolo)ies to make tin)s &amiliar$ !espite all o8r best e&&orts, (eA'e not been 'er in'enti'e$ In te *est, ea'en is plaid and &l8&&, and ell is like te inside o& a 'olano$ In man stories, bot realms are )o'erned b dominane ieraries eaded b )ods or de'ils$ onoteists talked abo8t te kin) o& kin)s$ In e'er 8lt8re (e ima)ined sometin) like o8r o(n politial sstem r8nnin) te ni'erse$ %e( &o8nd te similarit s8spiio8s$ en siene ame alon) and ta8)t 8s tat (e are not te meas8re o& all tin)s, tat tere are (onders 8nima)ined, tat te ni'erse is not obli)ed to on&orm to (at (e onsider om&ortable or pla8sible$ *e a'e learned sometin) abo8t te idiosnrati nat8re o& o8r ommon sense$ Siene as arried 8man sel&-onsio8sness to a i)er le'el$ is is s8rel a rite o& passa)e, a step to(ards mat8rit$ It ontrasts starkl (it te ildisness and narissism o& o8r pre-+opernian notions$ B8t ( so8ld (e (ant to tink tat te ni'erse (as made &or 8sD * is te idea so appealin)D * do (e n8rt8re itD Is o8r sel&-esteem so preario8s tat notin) sort o& a 8ni'erse 8stom-made &or 8s (ill doD 2& o8rse it appeals to o8r 'anit$ *at a man desires, e also ima)ines to be tr8e, said !emostenes$ e li)t o& &ait makes 8s see (at (e belie'e, eer&8ll admitted St$ omas K8inas$ B8t I tink tere ma be sometin) else$ ereAs a kind o& etnoentrism amon) primates$ o (ie'er little )ro8p (e appen to be born, (e o(e passionate lo'e and loalt$ embers o& oter )ro8ps are beneat ontempt, deser'in) o& reHetion and ostilit$ at bot )ro8ps are$ o& te same speies, tat to an o8tside obser'er te are 'irt8all indistin)8isable, makes no di&&erene$ is is ertainl te pattern amon) te impanees, o8r losest relati'es in te animal kin)dom$ nn !r8an and I a'e desribed o( tis (a o& 'ie(in) te (orld ma a'e made enormo8s e'ol8tionar sense a &e( million ears a)o, o(e'er dan)ero8s it as beome toda$ E'en members o& 8nter-)aterer )ro8psGas &ar &rom te tenolo)ial &eats o& o8r present )lobal i'iliation as it is possible &or 8mans to beGsolemnl desribe teir little band, (ie'er it is, as te people$ E'erone else is sometin) di&&erent, sometin) less tan 8man$ I& tis is o8r nat8ral (a o& 'ie(in) te (orld, ten it so8ld oasion no s8rprise tat e'er time (e make a nai'e H8d)ment abo8t o8r plae in te ni'erseGone 8ntempered b are&8l and skeptial sienti&i eCaminationG(e almost al(as opt &or te entralit o& o8r )ro8p and ir8mstane$ *e (ant to belie'e, moreo'er, tat tese are obHeti'e &ats, and not o8r preH8dies &indin) a santioned 'ent$ So itAs not m8 &8n to a'e a )a))le o& sientists inessantl aran)8in) 8s (it o8Are ordinar, o8Are 8nimportant o8r pri'ile)es are 8ndeser'ed, tereAs notin) speial abo8t o8$ E'en 8neCitable people mi)t, a&ter a (ile, )ro( annoed at tis inantation and tose (o insist on antin) it$ It almost seems tat te sientists are )ettin) some (eird satis&ation o8t o& p8ttin) 8mans do(n$ * anAt te &ind a (a in (i (eAre s8periorD .i&t o8r spiritsF ECalt 8sF In s8 debates siene, (it its mantra o& diso8ra)ement, &eels old and remote, dispassionate, detaed, 8nresponsi'e to 8man needs$
3"
nd, a)ain, i& (eAre not important, not entral, not te apple o& /odAs ee, (at is implied &or o8r teolo)iall based moral odesD e diso'er o& o8r tr8e bearin)s in te +osmos (as resisted &or so lon) and to s8 a de)ree tat man traes o& te debate remain, sometimes (it te moti'es o& te )eoentrists laid bare$ ere, &or eCample, is a re'ealin) 8nsi)ned ommentar in te Britis re'ie( /e Spe7"a"or in 1;9": QIRt is ertain eno8) tat te diso'er o& te elioentri motion o& te planets (i red8ed o8r eart to its proper insi)ni&iane in te solar sstem, did a )ood deal to red8e to a similar b8t &ar &rom proper insi)ni&iane te moral priniples b (i te predominant raes o& te eart ad iterto been )8ided and restrained$ art o& tis e&&et (as no do8bt d8e to te e'idene a&&orded tat te psial siene o& 'ario8s inspired (riters (as erroneo8s instead o& bein) in&allible,-a on'ition (i 8nd8l sook te on&idene &elt e'en in teir moral and reli)io8s teain)$ B8t a )ood deal o& it (as d8e onl to te mere sense o& insi)ni&iane (it (i man as ontemplated imsel&, sine e as diso'ered tat e inabits notin) b8t a 'er obs8re orner o& te 8ni'erse, instead o& te entral (orld ro8nd (i s8n, moon, and stars alike re'ol'ed$ ere an be no do8bt tat man ma &eel imsel&, and as o&ten &elt imsel&, a )reat deal too insi)ni&iant to be te obHet o& an parti8lar di'ine trainin) or are$ I& te eart be re)arded as a sort o& ant-ill, and te li&e and deat o& 8man bein)s as te li&e and deat o& so man ants (i r8n into and o8t o& so man oles in sear o& &ood and s8nli)t, it is K8ite ertain tat no adeK8ate importane (ill be attaed to te d8ties o& 8man li&e, and tat a pro&o8nd &atalism and opelessness, instead o& ne( ope&8lness, (ill atta to 8man e&&ort $ $ $ Q%Ror te present at least, o8r orions are K8ite 'ast eno8) $ $ $ ? till (e an )et 8sed to te in&inite orions (e alread a'e, and not lose o8r balane so m8 as (e 8s8all do in ontemplatin) tem, te earnin) &or still (ider orions is premat8re$
WHAT DO WE REALLY WANT&rom
pilosop and reli)ionD alliati'esD erapD +om&ortD !o (e (ant reass8rin) &ables or an 8nderstandin) o& o8r at8al ir8mstanesD !isma tat te ni'erse does not on&orm to o8r pre&erenes seems ildis$ o8 mi)t tink tat )ro(n-8ps (o8ld be asamed to p8t s8 disappointments into print$ e &asionable (a o& doin) tis is not to blame te ni'erseG(i seems tr8l pointlessGb8t rater to blame te means b (i (e kno( te ni'erse, namel siene$ /eor)e Bernard Sa(, in te pre&ae to is pla St$ >oan, desribed a sense o& siene prein) on o8r red8lit, &orin) on 8s an alien (orld'ie(, intimidatin) belie&: In te iddle )es, people belie'ed tat te Eart (as &lat, &or (i te ad at least te e'idene o& teir senses: (e belie'e it to be ro8nd, not bea8se as man as one per ent o& 8s o8ld )i'e te psial reason &or so K8aint a belie&, b8t bea8se modern siene as on'ined 8s tat notin) tat is ob'io8s is tr8e, and tat e'ertin) tat is ma)ial, improbable, eCtraordinar, )i)anti, mirosopi, eartless, or o8tra)eo8s is sienti&i$
more reent and 'er instr8ti'e eCample is Understanding te Present: Science 33
and the Soul o Moern Man b Bran ppleard, a Britis Ho8rnalist$ is book makes eCpliit (at man people &eel, all o'er te (orld, b8t are too embarrassed to sa$ ppleardAs andor is re&resin)$ e is a tr8e belie'er and (ill not let 8s slo8) o'er te ontraditions bet(een modern siene and traditional reli)ion: Siene as taken a(a o8r reli)ion, e laments$ nd (at sort o& reli)ion is it tat e lon)s &orD 2ne in (i te 8man rae (as te point, te eart, te &inal a8se o& te (ole sstem$ It plaed o8r sel'es de&initi'el 8pon te 8ni'ersal map$ $ $ $ *e (ere te end, te p8rpose, te rational aCle aro8nd (i te )reat aeterian sells rotated$ e lon)s &or te 8ni'erse o& +atoli ortodoC in (i te osmos is so(n to be a maine onstr8ted aro8nd te drama o& sal'ationGb (i ppleard means tat, despite eCpliit orders to te ontrar, a (oman and a man one ate o& an apple, and tat tis at o& ins8bordination trans&ormed te ni'erse into a ontri'ane &or operant-onditionin) teir remote desendants$ B ontrast, modern siene presents 8s as aidents$ *e are a8sed b te osmos, b8t (e are not te a8se o& it$ odem man is not &inall antin), e as no role in reation$ Siene is spirit8all orrosi'e, b8rnin) a(a anient a8torities and traditions$ It annot reall o-eCist (it antin)$ $ $ $ Siene, K8ietl and ineCpliitl, is talkin) 8s into abandonin) o8r sel'es, o8r tr8e sel'es$ It re'eals te m8te, alien spetale o& nat8re$ $ $ $ 8man bein)s annot li'e (it s8 a re'elation$ e onl moralit le&t is tat o& te onsolin) lie$ ntin) is better tan )rapplin) (it te 8nbearable b8rden o& bein) tin$ In a passa)e reminisent o& l8s I, ppleard e'en deries te &at tat a modern demora an be eCpeted to inl8de a n8mber o& ontraditor reli)io8s &aits (i are obli)ed to a)ree on a ertain limited n8mber o& )eneral inH8ntions, b8t no more$ e m8st not b8rn ea oterAs plaes o& (orsip, b8t te ma den, e'en ab8se ea oterAs /od$ is is te e&&eti'e, sienti&i (a o& proeedin)$ B8t (at is te alternati'eD 2bd8ratel to pretend to ertaint in an 8nertain (orldD o adopt a om&ortin) belie& sstem, no matter o( o8t o& kilter (it te &ats it isD I& (e donAt kno( (atAs real, o( an (e deal (it realitD %or pratial reasons, (e annot li'e too m8 in &antasland$ Sall (e ensor one anoterAs reli)ions and b8rn do(n one anoterAs plaes o& (orsipD o( an (e be s8re (i o& te to8sands o& 8man belie& sstems so8ld beome 8nallen)ed, 8biK8ito8s, mandatorD ese K8otations betra a &ail8re o& ner'e be&ore te ni'erse its )rande8r and ma)ni&iene, b8t espeiall its indi&&erene$ Siene as ta8)t 8s tat, bea8se (e a'e a talent &or deei'in) o8rsel'es, s8bHeti'it ma not &reel rei)n$ is is one reason ppleard so mistr8sts siene: It seems too reasoned, meas8red, and impersonal$ Its onl8sions deri'e &rom te interro)ation o& Nat8re, and are not in all ases predesi)ned to satis& o8r (ants$ ppleard deplores moderation$ e earns &or inerrant dotrine, release &rom te eCerise o& H8d)ment, and an obli)ation to belie'e b8t not to K8estion$ e as not )rasped 8man &allibilit$ e reo)nies no need to instit8tionalie error-orretin) mainer eiter in o8r soial instit8tions or in o8r 'ie( o& te ni'erse$ is is te an)8ised r o& te in&ant (en te arent does not ome$ B8t most people e'ent8all ome to )rips (it realit, and (it te pain&8l absene o& parents (o (ill absol8tel )8arantee tat no arm be&alls te little ones so lon) as te do (at te are told$ E'ent8all most people &ind (as to aommodate to te ni'erseGespeiall (en )i'en te tools to
34
tink strai)t$ ll tat (e pass on to o8r ildren in te sienti&i a)e, ppleard omplains, is te on'ition tat notin) is tr8e, &inal or end8rin), inl8din) te 8lt8re &rom (i te spran)$ o( ri)t e is abo8t te inadeK8a o& o8r le)a$ B8t (o8ld it be enried b addin) baseless ertaintiesD e sorns te pio8s ope tat siene and reli)ion are independent realms (i an easil be separated$ Instead, siene, as it is no(, is absol8tel not ompatible (it reli)ion$ B8t isnAt ppleard reall sain) tat some reli)ions no( &ind it di&&i8lt to make 8nallen)ed prono8nements on te nat8re o& te (orld tat are strai)t-o8t &alseD *e reo)nie tat e'en re'ered reli)io8s leaders, te prod8ts o& teir time as (e are o& o8rs, ma a'e made mistakes$ eli)ions ontradit one anoter on small matters, s8 as (eter (e so8ld p8t on a at or take one o&& on enterin) a o8se o& (orsip, or (eter (e so8ld eat bee& and ese( pork or te oter (a aro8nd, all te (a to te most entral iss8es, s8 as (eter tere are no )ods, one /od, or man )ods$ Siene as bro8)t man o& 8s to tat state in (i Nataniel a(torne &o8nd erman el'ille: e an neiter belie'e, nor be om&ortable in is 8nbelie&$ 2r >ean->aK8es o8ssea8: e ad not pers8aded me, b8t te ad tro8bled me$ eir ar)8ments ad saken me (ito8t e'er on'inin) me $ $ $ It is ard to pre'ent onesel& &rom belie'in) (at one so keenl desires$ s te belie& sstems ta8)t b te se8lar and reli)io8s a8torities are 8ndennined, respet &or a8torit in )eneral probabl does erode$ e lesson is lear: E'en politisR leaders m8st be (ar o& embrain) &alse dotrine$ is is not a &ailin) o& siene, b8t one o& its )raes$ 2& o8rse, (orld'ie( onsens8s is om&ortin), (ile lases o& opinion ma be 8nsettlin), and demand more o& 8s$ B8t 8nless (e insist, a)ainst all e'idene, tat o8r anestors (ere per&et, te ad'ane o& kno(led)e reK8ires 8s to 8nra'el and ten restit te onsens8s te establised$ In some respets, siene as &ar s8rpassed reli)ion in deli'erin) a(e$ o( is it tat ardl an maHor reli)ion as looked at siene and onl8ded, is is better tan (e to8)tF e ni'erse is m8 bi))er tan o8r propets said, )rander, more s8btle, more ele)ant$ /od m8st be e'en )reater tan (e dreamedD Instead te sa, No, no, noF )od is a little )od, and I (ant im to sta tat (a$ reli)ion, old or ne(, tat stressed te ma)ni&iene o& te ni'erse as re'ealed b modern siene mi)t be able to dra( &ort reser'es o& re'erene and a(e ardl tapped b te on'entional &aits$ Sooner or later, s8 a reli)ion (ill emer)e$
IF YOU LIVEDt(o
or tree millennia a)o, tere (as no same in oldin) tat te ni'erse (as made &or 8s$ It (as an appealin) tesis onsistent (it e'ertin) (e kne(? it (as (at te most learned amon) 8s ta8)t (ito8t K8ali&iation$ B8t (e a'e &o8nd o8t m8 sine ten$ !e&endin) s8 a position toda amo8nts to (ill&8l disre)ard o& te e'idene, and a &li)t &rom sel&-kno(led)e$ Still, &or man o& 8s, tese depro'inialiations rankle$ E'en i& te do not &8ll antA te da, te erode on&ideneG8nlike te app antropoentri ertit8des, ripplin) (it soial 8tilit, o& an earlier a)e$ *e lon) to be ere &or a p8rpose, e'en to8), despite m8 sel&-
35
deeption, none is e'ident$ e meanin)less abs8rdit o& li&e, (rote .eo olsto, is te onl inontestable kno(led)e aessible to man$ 28r time is b8rdened 8nder te 8m8lati'e (ei)t o& s8essi'e deb8nkin)s o& o8r oneits: *eAre >onn-ome-latelies$ *e li'e in te osmi boondoks$ *e emer)ed &rom mirobes and m8k$ pes are o8r o8sins$ 28r to8)ts and &eelin)s are not &8ll 8nder o8r o(n ontrol$ ere ma be m8 smarter and 'er di&&erent bein)s else(ere$ nd on top o& all tis, (eAre makin) a mess o& o8r planet and beomin) a dan)er to o8rsel'es$ e trapdoor beneat o8r &eet s(in)s open$ *e &ind o8rsel'es in bottomless &ree &all$ *e are lost in a )reat darkness, and tereAs no one to send o8t a sear part$ /i'en so ars a realit, o& o8rse (eAre tempted to s8t o8r ees and pretend tat (eAre sa&e and sn8) at ome, tat te &all is onl a bad dream$ *e lak onsens8s abo8t o8r plae in te ni'erse$ ere is no )enerall a)reed 8pon lon)term 'ision o& te )oal o& o8r speiesGoter tan, peraps, simple s8r'i'al$ Espeiall (en times are ard, (e beome desperate &or eno8ra)ement, 8nreepti'e to te litan o& )reat demotions and dased opes, and m8 more (illin) to ear tat (eAre speial, ne'er mind i& te e'idene is paper-tin$ I& it takes a little mt and rit8al to )et 8s tro8) a ni)t tat seems endless, (o amon) 8s annot smpatie and 8nderstandD B8t i& o8r obHeti'e is deep kno(led)e rater tan sallo( reass8rane, te )ains &rom tis ne( perspeti'e &ar o8t(ei) te losses$ 2ne (e o'erome o8r &ear o& bein) tin, (e &ind o8rsel'es on te tresold o& a 'ast and a(esome ni'erse tat 8tterl d(ar&sGin time, in spae, and in potentialGte tid antropoentri proseni8m o& o8r anestors$ *e )ae aross billions o& li)t-ears o& spae to 'ie( te ni'erse sortl a&ter te Bi) Ban), and pl8mb te &ine str8t8re o& matter$ *e peer do(n into te ore o& o8r planet, and te blain) interior o& o8r star$ *e read te )eneti lan)8a)e in (i is (ritten te di'erse skills and propensities o& e'er bein) on Eart$ *e 8no'er idden apters in te reord o& o8r o(n ori)ins, and (it some an)8is better 8nderstand o8r nat8re and prospets$ *e in'ent and re&ine a)ri8lt8re, (ito8t (i almost all o& 8s (o8ld star'e to deat$ *e reate mediines and 'aines tat sa'e te li'es o& billions$ *e omm8niate at te speed o& li)t, and (ip aro8nd te Eart in an o8r and a al&$ *e a'e sent doens o& sips to more tan se'ent (orlds, and &o8r spaera&t to te stars$ *e are ri)t to reHoie in o8r aomplisments, to be pro8d tat o8r speies as been able to see so &ar, and to H8d)e o8r merit in part b te 'er siene tat as so de&lated o8r pretensions$ o o8r anestors tere (as m8 in Nat8re to be a&raid o&Gli)tnin), storms, eartK8akes, 'olanos, pla)8es, dro8)t, lon) (inters$ eli)ions arose in part as attempts to propitiate and ontrol, i& not m8 to 8nderstand, te disorderl aspet o& Nat8re$ e sienti&i re'ol8tion permitted 8s to )limpse an 8nderlin) ordered ni'erse in (i tere (as a literal armon o& te (orlds =>oannes eplerAs prase<$ I& (e 8nderstand Nat8re, tere is a prospet o& ontrollin) it or at least miti)atin) te arm it ma brin)$ In tis sense, siene bro8)t ope$ ost o& te )reat depro'inialiin) debates (ere entered into (it no to8)t &or teir pratial impliations$ assionate and 8rio8s 8mans (ised to 8nderstand teir at8al ir8mstanes, o( 8niK8e or pedestrian te and teir (orld are, teir 8ltimate ori)ins and destinies, o( te ni'erse (orks$ S8rprisin)l, some o& tese debates a'e ielded te most pro&o8nd pratial bene&its$ e 'er metod o& matematial reasonin) tat Isaa Ne(ton
36
introd8ed to eCplain te motion o& te planets aro8nd te S8n as led to most o& te tenolo) Of o8r modern (orld$ e Ind8strial e'ol8tion, &or all its sortomin)s, is still te )lobal model o& o( an a)ri8lt8ral nation an emer)e &rom po'ert$ ese debates a'e bread-andb8tter onseK8enes$ It mi)t a'e been oter(ise$ It mi)t a'e been tat te balane la else(ere, tat 8mans b and lar)e did not (ant to a( abo8t a disK8ietin) ni'erse, tat (e (ere 8n(illin) to ermit allen)es to te pre'ailin) (isdom$ !espite determined resistane in e'er a)e, it is 'er m8 to o8r redit tat (e a'e allo(ed o8rsel'es to &ollo( te e'idene, to dra( onl8sions tat at &irst seem da8ntin): a ni'erse so m8 lar)er and older tat o8r personal and istorial eCperiene is d(ar&ed and 8mbled, a ni'erse in (i, e'er da, s8ns are born and (orlds obliterated, a ni'erse in (i 8manit, ne(l arri'ed, lin)s to an obs8re lod o& matter$ o( m8 more satis&in) ad (e been plaed in a )arden 8stom-made &or 8s, its oter o8pants p8t tere &or 8s to 8se as (e sa( &it$ ere is a elebrated stor in te *estern tradition like tis, eCept tat not K8ite e'ertin) (as tere &or 8s$ ere (as one parti8lar tree o& (i (e (ere not to partake, a tree o& kno(led)e$ no(led)e and 8nderstandin) and (isdom (ere &orbidden to 8s in tis stor$ *e (ere to be kept i)norant$ B8t (e o8ldnAt elp o8rsel'es$ *e (ere star'in) &or kno(led)eGreated 8n)r, o8 mi)t sa$ is (as te ori)in o& all o8r tro8bles$ In parti8lar, it is ( (e no lon)er li'e in a )arden: *e &o8nd o8t too m8$ So lon) as (e (ere in8rio8s and obedient, I ima)ine, (e o8ld onsole o8rsel'es (it o8r importane and entralit, and tell o8rsel'es tat (e (ere te reason te ni'erse (as made$ s (e be)an to ind8l)e o8r 8riosit, to8), to eCplore, to learn o( te ni'erse reall is, (e eCpelled o8rsel'es &rom Eden$ n)els (it a &lamin) s(ord (ere set as sentries at te )ates o& aradise to bar o8r ret8rn$ e )ardeners beame eCiles and (anderers$ 2asionall (e mo8rn tat lost (orld, b8t tat, it seems to me, is ma8dlin and sentimental$ *e o8ld not appil a'e remained i)norant &ore'er$ ere is in tis ni'erse m8 o& (at seems to e desi)n$ E'er time (e ome 8pon it, (e breate a si) o& relie&$ *e are &ore'er opin) to &ind, or at least sa&el ded8e, a !esi)ner$ B8t instead, (e repeatedl diso'er tat nat8ral proessesGollisional seletion o& (orlds, sa, or nat8ral seletion o& )ene pools, or e'en te on'etion pattern in a pot o& boilin) (aterGan eCtrat order o8t o& aos, and deei'e 8s into ded8in) p8rpose (ere tere is none$ In e'erda li&e, (e o&ten senseGin te bedrooms o& teena)ers, or in national politisGtat aos is nat8ral, and order imposed &rom abo'e$ *ile tere are deeper re)8larities in te ni'erse tan te simple ir8mstanes (e )enerall desribe as orderl, all tat order, simple and ompleC, seems to deri'e &rom la(s o& Nat8re estab lised at te Bi) Ban) =or earli er<, rater tan as a onseK8ene o& belated inter'ention b an imper&et deit$ /od is to be &o8nd in te details is te &amo8s dit8m o& te /erman solar b8 *arb8r)$ B8t, amid m8 ele)ane and preision, te details o& li&e and te ni'erse also eCibit apaard, H8r-ri))ed arran)ements and m8 poor plannin)$ *at sall (e make o& tis: an edi&ie abandoned earl in onstr8tion b te aritetD e e'idene, so &ar at least and la(s o& Nat8re aside, does not reK8ire a !esi)ner$ abe tere is one idin), maddenin)l 8n(illin) to be re'ealed$ Sometimes it seems a 'er slender ope$ e si)ni&iane o& o8r li'es and o8r &ra)ile planet is ten determined onl b o8r o(n
37
(isdom and o8ra)e$ *e are te 8stodians o& li&eAs meanin)$ *e lon) &or a arent to are &or 8s, to &or)i'e 8s o8r errors, to sa'e 8s &rom o8r ildis mistakes$ B8t kno(led)e is pre&erable to i)norane$ Better b &ar to embrae te ard tr8t tan a reass8rin) &able$ I& (e ra'e some osmi p8rpose, ten let 8s &ind o8rsel'es a (ort )oal$
3;
+
E
5
IS EE INE..I/EN .I%E 2N ED e Ho8rneed a lon) time and &o8nd notin)$ t len)t te diserned a small li)t, (i (as te Eart $ $ $ QB8tR te o8ld not &ind te smallest reason to s8spet tat (e and o8r &ello(Gitiens o& tis )lobe a'e te onor to eCist$ G#2.IE, M!#OME%AS3 A P!&OSOP!#A& !S/O, (1*52)
Tere are pla7e in an aroun our grea" 7i"ie <ere "e na"ural u" "e ;rig" lig" o "e ;ig 7i"ie ;lea7 ou" "e "ar an e4en "a" pa"7 o ;lue i ome"ime gone "in"e ;rou" a e< unre mile up or o
enterin) YOU'RE AN ALIEN EXPLORER
te Solar Sstem a&ter a lon) Ho8rne tro8) te
blakness o& interstellar spae$ o8 eCamine te planets o& tis 8mdr8m star &rom a&arGa prett and&8l, some )ra, some bl8e, some red, some ello($ o8Are interested in (at kinds o& (orlds tese are, (eter teir en'ironments are stati or an)in), and espeiall (eter tere are li&e and intelli)ene$ o8 a'e no prior kno(led)e o& te Eart$ o8A'e H8st diso'ered its eCistene$
39
ereAs a )alati eti, letAs ima)ine: .ook b8t donAt to8$ o8 an &l b tese (orlds? o8 an orbit tem? b8t o8 are stritl &orbidden to land$ nder s8 onstraints, o8ld o8 &i)8re o8t (at te EartAs en'ironment is like and (eter anone li'es tereD s o8 approa, o8r &irst impression o& te (ole Eart is (ite lo8ds, (ite polar aps, bro(n ontinents, and some bl8is s8bstane tat o'ers t(o tirds o& te s8r&ae$ *en o8 take te temperat8re o& tis (orld &rom te in&rared radiation it emits, o8 &ind tat most latit8des are abo'e te &reein) point o& (ater, (ile te polar aps are belo( &reein)$ *ater is a 'er ab8ndant material in te ni'erse? polar aps made o& solid (ater (o8ld be a reasonable )8ess, as (ell as lo8ds o& solid and liK8id (ater$ o8 mi)t also e tempted b te idea tat te bl8e st8&& is enormo8s K8antitiesG kilometers deepGo& liK8id (ater$ e s8))estion is biarre, to8), at least as &ar as tis solar sstem is onerned, bea8se s8r&ae oeans o& liK8id (ater eCist no(ere else$ *en o8 look in te 'isible and near-in&rared spetr8m &or telltale si)nat8res o& emial omposition, s8re eno8) o8 diso'er (ater ie in te polar aps, and eno8) (ater 'apor in te air to ao8nt &or te lo8ds? tis is also H8st te ri)t amo8nt tat m8st eCist bea8se o& e'aporation i& te oeans are in &at made o& liK8id (ater$ e biarre potesis is on&irmed$ e spetrometers &8rter re'eal tat te air on tis (orld is one &i&t oC)en, 2 "$ No oter planet in te Solar Sstem as antin) lose to so m8 oC)en$ *ere does it all ome &romD e intense 8ltra'iolet li)t &rom te S8n breaks (ater, "0, do(n into oC)en and dro)en, and dro)en, te li)test )as, K8ikl esapes to spae$ is is a so8re o& 2 ", ertainl, b8t it doesnAt easil ao8nt &or so m8 oC)en$ noter possibilit is tat ordinar 'isible li)t, (i te S8n po8rs o8t in 'ast amo8nts, is 8sed on Eart to break (ater apartGeCept tat tereAs no kno(n (a to do tis (ito8t li&e$ ere (o8ld a'e to be plants, li&e-&orms olored b a pi)ment tat stron)l absorbs 'isible li)t, tat kno(s o( to split a (ater mole8le b sa'in) 8p te ener) o& t(o potons o& li)t, tat retains te and eCretes te 2, and tat 8ses te dro)en t8s liberated to sntesie or)ani mole8les$ e plants (o8ld a'e to be spread o'er m8 o& te planet$ ll tis is askin) a lot$ I& o8Are a )ood skeptial sientist, so m8 2 (o8ld not be proo& o& li&e$ B8t it ertainl mi)t be a8se &or s8spiion$ *it all tat oC)en o8Are not s8rprised to diso'er oone =2 3< in te atmospere, bea8se 8ltra'iolet li)t makes oone o8t o& mole8lar oC)en =2 "<$ e oone ten absorbs dan)ero8s 8ltra'iolet radiation$ So i& te oC)en is d8e to li&e, tereAs a 8rio8s sense in (i te li&e is protetin) itsel&$ B8t tis li&e ni)t be mere potosnteti plants$ i) le'el o& intelli)ene is not implied$ *en o8 eCamine te ontinents more losel, o8 &ind tere are, r8del speakin), t(o kinds o& re)ions$ 2ne so(s te spetr8m o& ordinar roks and minerals as &o8nd on man (orlds$ e oter re'eals sometin) 8n8s8al: a material, o'erin) 'ast areas, tat stron)l absorbs red li)t$ =e S8n, o& o8rse, sines in li)t o& all olors, (it a peak in te ello($< is pi)ment mi)t be H8st te a)ent needed i& ordinar 'isible li)t is bein) 8sed to break (ater apart and ao8nt &or te oC)en in te air$ ItAs anoter int, tis time a little stron)er, o& li&e, not
40
a b8) ere and tere, b8t a planetar s8r&ae o'er&lo(in) (it li&e$ e pi)ment is in &at loropll: It absorbs bl8e li)t as (ell as red, and is responsible &or te &at tat plants are )reen$ *at o8Are seein) is a densel 'e)etated planet$ So te Eart is re'ealed to possess tree properties 8niK8e at least in tis solar sstemG oeans, oC)en, li&e$ ItAs ard not to tink teAre related, te oeans bein) te sites o& ori)in, and te oC)en te prod8t, o& ab8ndant li&e$ *en o8 look are&8ll at te in&rared spetr8m o& te Eart, o8 diso'er te minor onstit8ents o& te air$ In addition to (ater 'apor, tereAs arbon dioCide =+2 "<, metane =+4<, and oter )ases tat absorb te eat tat te Eart tries to radiate a(a to spae at ni)t$ ese )ases (arm te planet$ *ito8t tem, te Eart (o8ld e'er(ere be belo( te &reein) point o& (ater$ o8A'e diso'ered tis (orldAs )reeno8se e&&et$ etane and oC)en to)eter in te same atmospere is pe8liar$ e la(s o& emistr are 'er lear: In an eCess o& 2 ", +4 so8ld be entirel on'erted into "2 and +2", e proess is so e&&iient tat not a sin)le mole8le in all te EartAs atmospere so8ld be metane$ Instead, o8 &ind tat one o8t o& e'er million mole8les is metane, ail immense disrepan$ *at o8ld it meanD e onl possible eCplanation is tat metane is bein) inHeted into te EartAs atmospere so K8ikl tat its emial reation (it 2 anAt keep pae$ *ere does all tis metane ome &romD abe it seeps o8t o& te deep interior o& te EartGb8t K8antitati'el tis doesnAt seem to (ork, and ars and #en8s donAt a'e antin) like tis m8 metane$ e onl alternati'es are biolo)ial, a onl8sion tat makes no ass8mptions abo8t te emistr o& li&e, or (at it looks like, b8t &oll o(s merel &rom o( 8nst able metane is in an oC)en atmospere$ In &at, te metane arises &rom s8 so8res as bateria in bo)s, te 8lti'ation o& rie, te b8rnin) o& 'e)etation, nat8ral )as &rom oil (ells, and bo'ine &lat8lene$ In an oC)en atmospere, metane is a si)n o& li&e$ at te intimate intestinal ati'ities o& o(s so8ld be detetable &rom interplanetar spae is a little disonertin), espeiall (en so m8 o& (at (e old dear is not$ B8t an alien sientist &lin) b te Eart (o8ld, at tis point, be 8nable to ded8e bo)s, rie, &ire, oil, or o(s$ >8st li&e$ ll te si)ns o& li&e tat (eA'e dis8ssed so &ar are d8e to omparati'el simple &orms =te metane in te r8mens o& o(s is )enerated b bateria tat omestead tere<$ ad o8r spaera&t &lo(n b te Eart a 8ndred million ears a)o, in te a)e o& te dinosa8rs (en tere (ere no 8mans and no tenolo), o8 (o8ld still a'e seen oC)en and oone, te loropll pi)ment, and &ar too m8 metane$ t present, to8), o8r instr8ments are &indin) si)ns not H8st o& li&e, b8t o& i) tenolo)Gsometin) tat o8ldnAt possibl a'e been deteted e'en a 8ndred ears a)o: o8 are detetin) a parti8lar kind o& radio (a'e emanatin) &rom Eart$ adio (a'es donAt neessaril si)ni& li&e and intelli)ene an nat8ral proesses )enerate tem$ o8A'e alread &o8nd radio emissions &rom oter, apparentl 8ninab ited (orldsG)enerated b eletrons trapped in te stron) ma)neti &ields o& planets, b aoti motions at te sok &ront
41
tat separates tese ma)neti &ields &rom te interplanetar ma)neti &ield, and b li)tnin)$ =adio (istlers 8s8all s(eep &rom i) notes to lo(, and ten be)in a)ain$< Some o& tese radio emissions are ontin8o8s? some ome in repetiti'e b8rsts? some last a &e( min8tes and ten disappear$ B8t tis is di&&erent: portion o& te radio trans mission &rom Eart is at H8st te &reK8enies (ere radio (a'es be)in to leak o8t o& te planetAs ionospere, te eletriall ar)ed re)ion abo'e te stratospere tat re&lets and absorbs radio (a'es$ ere is a onstant entral &reK8en &or ea transmission, added to (i is a mod8lated si)nal =a ompleC seK8ene o& ons and o&&s<$ No eletrons in ma)neti &ields, no sok (a'es, no li)tnin) disar)es an )enerate sometin) like tis$ Intelli)ent li&e seems to be te onl possible eCplanation$ o8r onl8sion tat te radio transmission is d8e to tenolo) on Eart olds no matter (at te ons and o&&s mean: o8 donAt a'e to deode te messa)e to be s8re it is a messa)e$ =is si)nal is reall, let 8s s8ppose, omm8niations &rom te $S$ Na' to its distant n8lear-armed s8bmarines$< So, as an alien eCplorer, o8 (o8ld kno( tat at least one speies on Eart as aie'ed radio tenolo)$ *i one is itD e bein)s tat make metaneD ose tat )enerate oC)enD e ones (ose pi)ment olors te landsape )reenD 2r somebod else, somebod more s8btle, someone not oter(ise detetable to a spaera&t pl8mmetin) bD o sear &or tis tenolo)ial speies, o8 mi)t (ant to eCamine te Eart at &iner and &iner resol8tionG seekin), i& not te bein)s temsel'es, at least teir arti&ats$ o8 look &irst (it a modest telesope, so te &inest detail o8 an resol'e is one or t(o kilometers aross$ o8 an make o8t no mon8mental aritet8re, no stran)e &ormations, no 8nnat8ral re(orkin) o& te landsape, no si)ns o& li&e$ o8 see a dense atmospere in motion$ e ab8ndant (ater m8st e'aporate and ten rain bak do(n$ nient impat raters, apparent on te EartAs nearb oon, are almost (oll absent$ ere m8st, ten, be a set o& proesses (ereb ne( land is reated and ten eroded a(a in m8 less time tan te a)e o& tis (orld$ 8nnin) (ater is impliated$ s o8 look (it &iner and &iner de&inition o8 &ind mo8ntain ran)es, ri'er 'alles, and man oter indiations tat te planet is )eolo)iall ati'e$ ere are also odd plaes s8rro8nded b 'e)etation, b8t (i are temsel'es den8ded o& plants$ e look like disolored sm8d)es on te landsape$ *en o8 eCamine te Eart at abo8t 100-meter resol8tion, e'ertin) an)es$ e planet is re'ealed to be o'ered (it strai)t lines, sK8ares, retan)les, irlesGsometimes 8ddlin) alon) ri'er banks or nestlin) on te lo(er slopes o& mo8ntains, sometimes stretin) o'er plains, b8t rarel in deserts or i) mo8ntains, and absol8tel ne'er in te oeans$ eir re)8larit, ompleCit, and distrib8tion (o8ld be ard to eCplain eCept b li&e and intelli)ene, alto8) a deeper 8nderstandin) o& &8ntion and p8rpose mi)t be el8si'e$ eraps o8 (o8ld onl8de onl tat te dominant li&e-&orms a'e a sim8ltaneo8s passion &or territorialit and E8lidean )eometr$ t tis resol8tion o8 o8ld not see tem, m8 less kno( tem$ an o& te de'e)etated sm8d)es are re'ealed to a'e an 8nderlin) ekerboard )eometr$ ese are te planets ities$ 2'er m8 o& te landsape, and not H8st in te ities, tere is a pro&8sion o& strai)t lines, sK8ares, retan)les, irles$ e dark sm8d)es o& te ities 4"
are re'ealed to be i)l )eometried, (it onl a &e( pates o& 'e)etationGtemsel'es (it i)l re)8lar bo8ndariesGle&t intat$ ere are oasional trian)les, and in one it tere is e'en a penta)on$ *en o8 take pit8res at a meter resol8tion or better, o8 &ind tat te rissrossin) strai)t lines (itin te ities and te lon) strai)t lines tat Hoin tem (it oter ities are &illed (it streamlined, m8ltiolored bein)s a &e( meters in len)t, politel r8nnin) one beind te oter, in lon), slo( orderl proession$ e are 'er patient$ 2ne stream o& bein)s stops so anoter stream an ontin8e at ri)t an)les$ eriodiall, te &a'or is ret8rned$ t ni)t, te t8rn on t(o bri)t li)ts in &ront so te an see (ere teAre )oin)$ Some, a pri'ile)ed &e(, )o into little o8ses (en teir (orkda is done and retire &or te ni)t$ ost are omeless and sleep in te streets$ t lastF o8A'e deteted te so8re o& all te tenolo)$ te dominant li&e-&orms on te planet$ e streets o& te ities and te road(as o& te o8ntrside are e'identl b8ilt &or teir bene&it$ o8 mi)t belie'e tat o8 (ere reall be)innin) to 8nderstand li&e on Eart$ nd peraps o8Ad be ri)t$ I& te resol8tion impro'ed H8st a little &8rter, o8Ad diso'er tin parasites tat oasionall enter and eCit te dominant or)anisms$ e pla some deeper role, to8), bea8se a stationar dominant or)anism (ill o&ten start 8p a)ain H8st a&ter itAs rein&eted b a parasite, and stop a)ain H8st be&ore te parasite is eCpelled$ is is p8lin)$ B8t no one said li&e on Eart (o8ld be eas to 8nderstand$ ll te ima)es o8A'e taken so &ar are in re&leted s8nli)tGtat is, on te da side o& te planet$ Sometin) most interestin) is re'ealed (en o8 poto)rap te Eart at li)t: e planet is lit 8p$ e bri)test re)ion, near te rti +irle, is ill8minated b te a8rora borealis G)enerated not b li&e , b8t b eletrons and protons &rom te S8n, beamed do(n b te EartAs ma)neti &ield$ E'ertin) else o8 see is d8e to li&e$ e li)ts reo)niabl o8tline te same ontinents o8 an make o8t in datime? and man orrespond to ities o8A'e alread mapped$ e ities are onentrated near oastlines$ e tend to be sparser in ontinental interiors$ eraps te dominant or)anisms are desperate &or sea(ater =or mabe oean)oin) sips (ere one essential &or ommere and emi)ration<$ Some o& te li)ts, to8), are not d8e to ities$ In Nort &ria, te iddle East, and Siberia, &or eCample, tere are 'er bri)t li)ts in a omparati'el barren landsape d8e, it t8rns o8t, to b8rno&& in oil and nat8ral )as (ells$ In te Sea o& >apan on te da o8 &irst look, tere is a stran)e, trian)8lar-saped area o& li)t$ In datime it orresponds to open oean$ is is no it$ *at o8ld it beD It is in &at te >apanese sK8id &isin) &leet, 8sin) brilliant ill8mination to attrat sools o& sK8id 8p to teir deats$ 2n oter das, tis pattern o& li)t (anders all o'er te ai&i 2ean, seekin) pre$ In e&&et, (at o8 a'e diso'ered ere is s8si$ It seems soberin) to me tat &rom spae o8 an so readil detet some o& te odds and ends o& li&e on EartGte )astrointestinal abits o& r8minants, >apanese 8isine, te means o& omm8niatin) (it nomadi s8bmarines tat arr deat &or "00 itiesG(ile so m8 o& o8r
43
mon8mental aritet8re, o8r )reatest en)ineerin) (orks, o8r e&&orts to are &or one anoter, are almost (oll in'isible$ ItAs a kind o& parable$
BY THIS POINT
o8r eCpedition to te Eart m8st be onsidered i)l s8ess&8l$ o8A'e
arateried te en'ironment? o8A'e deteted li&e? o8A'e &o8nd mani&estations o& intelli)ent bein)s? o8 ma e'en a'e identi&ied te dominant speies, te one trans&iCed (it )eometr and retilinearit$ S8rel tis planet is (ort a lon)er and more detailed st8d$ atAs ( o8A'e no( inserted o8r spaera&t into orbit aro8nd te Eart$ .ookin) do(n on te planet, o8 8no'er ne( p8les$ ll o'er te Eart, smokestaks are po8rin) arbon dioCide and toCi emials into te air$ So are te dominant bein)s (o r8n on te road(as$ B8t arbon dioCide is a )reeno8se )as$ s o8 (at, te amo8nt o& it in te atmospere inreases steadil, ear a&ter ear$ e same is tr8e o& metane and oter )reeno8se )ases$ I& tis keeps 8p, te temperat8re o& te planet is )oin) to inrease$ Spetrosopiall, o8 diso'er anoter lass o& mole8les bein) inHeted into te air, te loro&l8oroarbons$ Not onl are te )reeno8se )ases, b8t te are also de'astatin)l e&&eti'e in destroin) te proteti'e oone laer$ o8 look more losel at te enter o& te So8t merian ontinent, (iGas o8 kno( b no(Gis a 'ast rain &orest$ E'er ni)t o8 see to8sands o& &ires$ In te datime, o8 &ind te re)ion o'ered (it smoke$ 2'er te ears, all o'er te planet, o8 &ind less and less &orest and more and more sr8b desert$ o8 look do(n on te lar)e island o& ada)asar$ e ri'ers are olored bro(n, )eneratin) a 'ast stain in te s8rro8ndin) oean$ is is topsoil bein) (ased o8t to sea at a rate so i) tat in anoter &e( deades tere (ill be none le&t$ e same tin) is appenin), o8 note, at te mo8ts o& ri'ers all o'er te planet$ B8t no topsoil means no a)ri8lt8re$ In anoter ent8r, (at (ill te eatD *at (ill te breateD o( (ill te ope (it a an)in) and more dan)ero8s en'ironmentD %rom o8r orbital perspeti'e, o8 an see tat sometin) as 8nmistakabl )one (ron)$ e dominant or)anisms, (oe'er te areG(o a'e )one to so m8 tro8ble to re(ork te s8r&aeGare sim8ltaneo8sl destroin) teir oone laer and teir &orests, erodin) teir topsoil, and per&ormin) massi'e, 8nontrolled eCperiments on teir planetAs limate$ a'enAt te notied (atAs appenin)D re te obli'io8s to teir &ateD re te 8nable to (ork to)eter on beal& o& te en'ironment tat s8stains tem allD eraps, o8 tink, itAs time to reassess te onHet8re tat tereAs intelli)ent li&e on Eart$
LO OK I NG
F O R L I FE E L S EW H ER E : A C A L I B R AT I O N
44
Spaera&t &rom te Eart a'e no( &lo(n b doens o& planets, moons, omets, and asteroids GeK8ipped (it ameras, instr8ments &or meas8rin) eat and radio (a'es, spetrometers to determine omposition, and a ost o& oter de'ies$ *e a'e &o8nd not a int o& li&e an(ere else in te Solar Sstem$ B8t o8 mi)t be skeptial abo8t o8r abilit to detet li&e else(ere, espeiall li&e di&&erent &rom te kind (e kno($ ntil reentl (e ad ne'er per&ormed te ob'io8s alibration test: to &l a modern interplanetar spaera&t b te Eart and see (eter (e o8ld detet o8rsel'es$ is all an)ed on !eember ;, 1990$ %alileo is a NS spaera&t desi)ned to eCplore te )iant planet >8piter, its moons, and its rin)s$ ItAs named a&ter te eroi Italian sientist (o plaed so entral a role in topplin) te )eoentri pretension$ It is e (o &irst sa( >8piter as a (orld, and (o diso'ered its &o8r bi) moons$ o )et to >8piter, te spaera&t ad to &l lose b #en8s =one< and te Eart =t(ie< and be aelerated b te )ra'ities o& tese planetsGoter(ise tere (asnAt eno8) oomp to )et it (ere it (as )oin)$ is neessit o& traHetor desi)n permitted 8s, &or te &irst time, to look sstematiall at te Eart &rom an alien perspeti'e$
%alileo passed onl 960 kilometers =abo8t 600 miles< abo'e te EartAs s8r&ae$ *it some eCeptionsGinl8din) pit8res so(in) &eat8res &iner tan 1 kilometer aross, and te ima)es o& te Eart at ni)tGm8 o& te spaera&t data desribed in tis apter (ere at8all obtained b %alileo. *it %alileo (e (ere able to ded8e an oC)en atmospere, (ater, lo8ds, oeans, polar ie, li&e, and intelli)ene$ e 8se o& instr8ments and protools de'eloped to eCplore te planets to monitor te en'ironmental ealt o& o8r o(nGsometin) NS is no( doin) in earnestG(as desribed b te astrona8t Sall ide as ission to lanet Eart$ 2ter members o& te NS sienti&i team (o (orked (it me on %alileo detetion o& li&e on Eart (ere !rs$ *$ eid ompson, +ornell ni'ersit? obert +arlson, >.? !onald /8rnett, ni'ersit o& Io(a? and +arles ord, ni'ersit o& +olorado$ 28r s8ess in detetin) li&e on Eart (it %alileo, (ito8t makin) an ass8mptions be&oreand abo8t (at kind o& li&e it m8st be, inreases o8r on&idene tat (en (e &ail to &ind li&e on oter planets, tat ne)ati'e res8lt is meanin)&8l$ Is tis H8d)ment antropoentri, )eoentri, pro'inialD I donAt tink so$ *eAre not lookin) onl &or o8r kind o& biolo)$ n (idespread potosnteti pi)ment, an )as )rossl o8t o& eK8ilibri8m (it te rest o& te atmospere, an renderin) o& te s8r&ae into i)l )eometried patterns, an stead onstellation o& li)ts on te ni)t emispere, an non-astropsial so8res o& radio emission (o8ld betoken te presene o& li&e$ 2n Eart (e a'e &o8nd o& o8rse onl o8r tpe, b8t man oter tpes (o8ld a'e been detetable else(ere$ *e a'e not &o8nd tem$ is eCamination o& te tird planet stren)tens o8r tentati'e onl8sion tat, o& all te (orlds in te Solar Sstem, onl o8rs is )raed b li&e$ *e a'e H8st be)8n to sear$ abe li&e is idin) on ars or >8piter, E8ropa or itan$ abe te /alaC is &illed (it (orlds as ri in li&e as o8rs$ abe (e are on te 'er)e o& makin) s8 diso'eries$ B8t in terms o& at8al kno(led)e, at tis moment te Eart is 8niK8e$ No oter (orld is et kno(n to arbor e'en a mirobe, m8 less a tenial i'iliation$
45
+
E
6
E I 2% #2/E e tat )o do(n to te sea in sips, tat do b8siness in )reat (aters? tese see te (orks o& te .ord, and is (onders in te deep$ GS.S, 107 =+$ 150 B$+<
Te 'isions (e o&&er o8r ildren sape te &8t8re$ It matters (at tose 'isions are$ 2&ten te beome sel&-&8l&illin) propeies$ !reams are maps$
46
I do not tink it irresponsible to portra e'en te direst &8t8res? i& (e are to a'oid tem, (e m8st 8nderstand tat te are possible$ B8t (ere are te alternati'esD *ere are te dreams tat moti'ate and inspireD *e lon) &or realisti maps o& a (orld (e an be pro8d to )i'e to o8r ildren$ *ere are te arto)rapers o& 8man p8rposeD *ere are te 'isions o& ope&8l &8t8res, o& tenolo) as a tool &or 8man betterment and not a )8n on air tri))er pointed at o8r eadsD NS, in its ordinar o8rse o& doin) b8siness, o&&ers s8 a 'ision$ B8t in te late 19;0s and earl A90s, man people sa( te $S$ spae pro)ram as, instead, a s8ession o& atastropes Gse'en bra'e merians killed on a mission (ose main &8ntion (as to p8t 8p a omm8niations satellite tat o8ld a'e been la8ned at less ost (ito8t riskin) anbod? a billion-dollar telesope sent 8p (it a bad ase o& mopia? a spaera&t to >8piter (ose main antennaGessential &or ret8rnin) data to EartGdid not 8n&8rl? a probe lost H8st as it (as abo8t to orbit ars$ Some people rin)e e'er time NS desribes as eCploration sendin) a &e( astrona8ts "00 miles 8p in a small aps8le tat endlessl irles te Eart and )oes no(ere$ +ompared to te brilliant aie'ements o& roboti missions, it is strikin) o( rarel &8ndamental sienti&i &indin)s emer)e &rom manned missions$ ECept &or repairin) ineptl man8&at8red or mal&8ntionin) satellites, or la8nin) a satellite tat o8ld H8st as (ell a'e been sent 8p in an 8nmanned booster, te manned pro)ram as, sine te 1970s, seemed 8nable to )enerate aomplisments ommens8rate (it te ost$ 2ters looked at NS as a stalkin) orse &or )randiose semes to p8t (eapons into spae, despite te &at tat an orbitin) (eapon is in man ir8mstanes a sittin) d8k$ nd NS so(ed man smptoms o& an a)in), arteriosleroti, o'era8tio8s, 8nad'ent8ro8s b8rea8ra$ e trend is peraps be)innin) to be re'ersed$ B8t tese ritiismsGman o& tem s8rel 'alidGso8ld not blind 8s to NS tri8mps in te same period: te &irst eCploration o& te ran8s and Nept8ne sstems, te in-orbit repair o& te 8bble spae telesope, te proo& tat te eCistene o& )alaCies is ompatible (it te Bi) Ban), te &irst lose-8p obser'ations o& asteroids, mappin) #en8s pole to pole, monitorin) oone depletion, demonstratin) te eCistene o& a blak ole (it te mass o& a billion s8ns at te enter o& a nearb )alaC, and a istori ommitment to Hoint spae endea'ors b te $S$ and 8ssia$ ere are &ar-reain), 'isionar, and e'en re'ol8tionar impliations to te spae pro)ram$ +omm8niations satellites link 8p te planet, are entral to te )lobal eonom, and, tro8) tele'ision, ro8tinel on'e te essential &at tat *e li'e in a )lobal omm8nit$ eteorolo)ial satellites predit te (eater, sa'e li'es in 8rrianes and tornados, and a'oid man billions o& dollars in rop losses e'er ear$ ilitar-reonnaissane and treat'eri&iation satellites make nations and te )lobal i'iliation more se8re? in a (orld (it tens o& to8sands o& n8lear (eapons, te alm te oteads and paranoids on all sides? te are essential tools &or s8r'i'al on a tro8bled and 8npreditable planet$ Eart-obser'in) satellites, espeiall a ne( )eneration soon to be deploed, monitor te ealt o& te )lobal en'ironment: )reeno8se (armin), topsoil erosion, oone laer depletion, oean 8rrents, aid rain, te e&&ets o& &loods and dro8)ts, and ne( dan)ers (e a'enAt et diso'ered$ is is strai)t&or(ard planetar )iene$
47
/lobal positionin) sstems are no( in plae so tat o8r loale is radio-trian)8lated b se'eral satellites$ oldin) a small instr8ment te sie o& a modern sort(a'e radio, o8 an read o8t to i) preision o8r latit8de and lon)it8de$ No rased airplane, no sip in &o) and soals, no dri'er in an 8n&amiliar it need e'er be lost a)ain$ stronomial satellites peerin) o8t(ard &rom EartAs orbit obser'e (it 8ns8rpassed larit Gst8din) K8estions ran)in) &rom te possible eCistene o& planets aro8nd nearb stars to te ori)in and &ate o& te ni'erse$ lanetar probes &rom lose ran)e eCplore te )or)eo8s arra o& oter (orlds in o8r solar sstem omparin) teir &ates (it o8rs$ ll o& tese ati'ities are &or(ard-lookin), ope&8l, stirrin) and ost-e&&eti'e$ None o& tem reK8ires manned 1 spae&li)t$ ke iss8e &ain) te &8t8re o& NS and addressed in tis book is (eter te p8rported H8sti&iations &or 8man spae&li)t are oerent and s8stainable$ Is it (ort te ostD B8t &irst, letAs onsider te 'isions o& a ope&8l &8t8re 'o8sa&ed b robot spaera&t o8t amon) te planets$ VOYAGER 1 N! VOYAGER 2 are
te sips tat opened te Solar Sstem &or te 8man speies,
trailblain) a pat &or &8t8re )enerations$ Be&ore teir la8n, in 8)8st and September 1977, (e (ere almost (oll i)norant abo8t most o& te planetar part o& te Solar Sstem$ In te neCt doen ears, te pro'ided o8r &irst detailed, lose-8p in&ormation on man ne( (orldsG some o& tem pre'io8sl kno(n onl as &8 disks in te eepiees o&
)ro8nd-based
telesopes, some merel as points o& li)t, and some (ose 'er eCistene (as 8ns8speted$ e are still ret8rnin) reams o& data$ ese spaera&t a'e ta8)t 8s abo8t te (onders o& oter (orlds, abo8t te 8niK8eness and &ra)ilit o& o8r o(n, abo8t be)innin)s and ends$ e a'e )i'en 8s aess to most o& te Solar SstemGbot in eCtent and in mass$ e are te sips tat &irst eCplored (at ma be omelands o& o8r remote desendants$ $S$ la8n 'eiles are tese das too &eeble to )et s8 a spaera&t to >8piter and beond in onl a &e( ears b roket prop8lsion alone$ B8t i& (eAre le'er =and l8k<, tereAs sometin) else (e an do: *e an =as /alileo also did, ears later< &l lose to one (orld, and a'e its )ra'it &lin) 8s on to te neCt$ )ra'it assist, itAs alled$ It osts 8s almost notin) b8t in)en8it$ ltAs sometin) like )rabbin) old o& a post on a mo'in) merr-)o-ro8nd as it passesG to speed o8 8p and &lin) o8 in some ne( diretion$ e spaera&tAs aeleration is ompensated &or b a deeleration in te planetAs orbital motion aro8nd te S8n$ B8t bea8se te planet is so massi'e ompared to te spaera&t, it slo(s do(n ardl at all$ Ea Vo$ager spaera&t piked 8p a 'eloit boost o& nearl 40,000 miles per o8r &rom >8piterAs )ra'it$ >8piter in t8rn (as slo(ed do(n in its motion aro8nd te S8n$ B o( m8D %i'e billion ears 1
Sine (omen astrona8ts and osmona8ts o& se'eral nations a'e &lo(n in spae, manned is H8st &lat-o8t inorret$ IA'e attempted to &ind an alternati'e to tis (idel 8sed term, oined in a more 8nsel&onsio8sl seCist a)e$ I tried re(ed &or a (ile, b8t in spoken lan)8a)e it lends itsel& to mis8nderstandin)$ iloted doesnAt (ork, bea8se e'en ommerial airplanes a'e robot pilots$ anned and (omanned is H8st, b8t 8n(ield$ eraps te best ompromise is 8man, (i permits 8s to distin)8is rispl bet(een 8man and roboti missions$ B8t e'er no( and ten, 1 &ind 8man not K8ite (orkin), and to m disma manned slips bak in$
4;
&rom no(, (en o8r S8n beomes a s(ollen red )iant, >8piter (ill be one millimeter sort o& (ere it (o8ld a'e been ad Vo$ager not &lo(n b it in te late t(entiet ent8r$
Vo$ager 2 took ad'anta)e o& a rare linin)-8p o& te planets: lose &lb o& >8piter aelerated it on to Sat8rn, Sat8rn to ran8s, ran8s to Nept8ne, and Nept8ne to te stars$ B8t o8 anAt do tis antime o8 like: e pre'io8s opport8nit &or s8 a )ame o& elestial billiards presented itsel& d8rin) te presiden o& omas >e&&erson$ *e (ere ten onl at te orsebak, anoe, and sailin) sip sta)e o& eCploration$ =Steamboats (ere te trans&ormin) ne( tenolo) H8st aro8nd te orner$< Sine adeK8ate &8nds (ere 8na'ailable, NSAs >et rop8lsion .aborator =>.< o8ld a&&ord to b8ild spaera&t tat (o8ld (ork reliabl onl as &ar as Sat8rn$ Beond tat, all bets (ere o&&$ o(e'er, bea8se o& te brilliane o& te en)ineerin) desi)n and te &at tat te >. en)ineers (o radioed instr8tions 8p to te spaera&t )ot smarter &aster tan te spaera&t )ot st8pidGbot spaera&t (ent on to eCplore ran8s and Nept8ne$ ese das te are broadastin) bak diso'eries &rom beond te most distant kno(n planet o& te S8n$ *e tend to ear m8 more abo8t te splendors ret8rned tan te sips tat bro8)t tem, or te sip(ri)ts$ It as al, (as been tat (a$ E'en tose istor books enamored o& te 'oa)es o& +ristoper +ol8mb8s do not tell 8s m8 abo8t te b8ilders o& te Nina, te inta, and te Santa aria, or abo8t te priniple o& te ara'el$ ese spaera&t, teir desi)ners, b8ilders, na'i)ators, and ontrollers are eCamples o& (at siene and en)ineerin), set &ree &or (ell-de&ined peae&8l p8rposes, an aomplis$ ose sientists and en)ineers so8ld be role models &or an meria seekin) eCellene and international ompetiti'eness$ e so8ld be on o8r stamps$ t ea o& te &o8r )iant planetsG>8piter, Sat8rn, ran8s, and Nept8neGone or bot spaera&t st8died te planet itsel&, its rin)s, and its moons$ t >8piter, in 1979, te bra'ed a dose o& trapped ar)ed partiles a to8sand times more intense tan (at it takes to kill a 8man? en'eloped in all tat radiation, te diso'ered te rin)s o& te lar)est planet, te &irst ati'e 'olanos o8tside Eart, and a possible 8nder)ro8nd oean on an airless (orldGamon) a ost o& s8rprisin) diso'eries$ t Sat8rn, in 19;0 and 19;1, te s8r'i'ed a bliard o& ie and &o8nd not a &e( ne( rin)s, b8t to8sands$ e eCamined &roen moons msterio8sl melted in te omparati'el reent past, and a lar)e (orld (it a p8tati'e oean o& liK8id droarbons s8rmo8nted b lo8ds o& or)ani matter$ 2n >an8ar "5, 19;6, Vo$ager 2entered te ran8s sstem and reported a proession o& (onders$ e eno8nter lasted onl a &e( o8rs, b8t te data &ait&8ll relaed bak to Eart a'e re'ol8tionied o8r kno(led)e o& te aK8amarine planet, its 15 moons$ its pit-blak rin)s, and its belt o& trapped i)-ener) ar)ed partiles$ 2n 8)8st "5, 19;9, Vo$ager 2 s(ept tro8) te Nept8ne sstem and obser'ed, diml ill8minated b te distant S8n, kaleidosopi lo8d patterns and a biarre moon on (i pl8mes o& &ine or)ani partiles (ere bein) blo(n abo8t b te astonisin)l tin air$ nd in 199", a'in) &lo(n beond te o8termost kno(n planet, bot Vo$ager piked 8p radio emission to8)t to emanate &rom te still remote eliopa8seGte plae (ere te (ind &rom te S8n )i'es (a to te (ind &rom te stars$
49
Bea8se (eAre st8k on Eart, (eAre &ored to peer at distant (orlds tro8) an oean o& distortin) air$ 8 o& te 8ltra'iolet, in&rared, and radio (a'es te emit do not penetrate o8r atmospere$ ItAs eas to see ( o8r spaera&t a'e re'ol8tionied te st8d o& te Solar Sstem: *e asend to stark larit in te 'a88m o& spae, and tere approa o8r obHeti'es, &lin) past tem, as did Vo$ager, or orbitin) tem, or landin) on teir s8r&aes$ ese spaera&t a'e ret8rned &o8r trillion bits o& in&ormation to Eart, te eK8i'alent o& abo8t 100,000 enlopedia 'ol8mes$ I desribed te Vo$ager 1 and 2 eno8nters (it te >8piter sstem in +osmos$ In te &ollo(in) pa)es, IAll sa sometin) abo8t te Sat8rn, ran8s, and Nept8ne eno8nters$
JUST BEFOREVOYAGER 2(as
to eno8nter te ran8s sstem, te mission desi)n ad spei&ied
a &inal mane8'er, a brie& &irin) o& te on-board prop8lsion sstem to position te spaera&t orretl so it o8ld tread its (a on a preset pat amon) te 8rtlin) moons$ B8t te o8rse orretion pro'ed 8nneessar$ e spaera&t (as alread (itin "00 kilometers o& its desi)ned traHetor-a&ter a Ho8rne alon) an arin) pat 5 billion kilometers lon)$ is is ro8)l te eK8i'alent o& tro(in) a pin tro8) te ee o& a needle 50 kilometers a(a, or &irin) o8r ri&le in *asin)ton and ittin) te b8llAs-ee in !allas$ oter lodes o& planetar treas8re (ere radioed bak to Eart$ B8t Eart is so &ar a(a tat b te time te si)nal &ro) Nept8ne (as )atered in b radio telesopes on o8r planet, te reei'ed po(er (as onl 10 -16 (atts =&i&teen eros bet(een te deimal point and te one<$ is (eak si)nal bears te same pro, portion to te po(er emitted b an ordinar readin) lamp as te diameter o& an atom bears to te distane &rom te Eart to te oon$ ItAs like earin) an amoebaAs &ootstep$ e mission (as onei'ed d8rin) te late 1960s$ It (as &irst &8nded in 197"$ B8t it (as not appro'ed in its &inal &orm =inl8din) te eno8nters (it ran8s and Nept8ne< 8ntil a&ter te sips ad ompleted teir reonnaissane o& >8piter$ e t(o spaera&t (ere li&ted o&& te Eart b a nonre8sable /i"anC#en"aur booster on&i)8ration$ *ei)in) abo8t a ton, a Vo$ager (o8ld &ill a small o8se$ Ea dra(s abo8t 400 (atts o& po(erGonsiderabl less tan an a'era)e merian omeG&rom a )enerator tat on'erts radioati'e pl8toni8m into eletriit$ =I& it ad to rel on solar ener), te a'ailable po(er (o8ld diminis K8ikl as te sip 'ent8red &arter and &arter &rom te S8n *ere it not &or n8lear po(er, Vo$ager (o8ld a'e ret8rned no data at all &rom te o8ter Solar Sstem, eCept peraps a little &rom >8piter$< e &lo( o& eletriit tro8) te innards o& te spaera&t (o8ld )enerate eno8) ma)netism to o'er(elm te sensiti'e instr8ment tat meas8res interplanetar ma)neti &ields$ So te ma)netometer is plaed at te end o& alon) boom, &ar &rom te o&&endin) eletrial 8rrents$ *it oter proHetions, it )i'es Vo$ager alter a sli)tl por8pine appearane$ +ameras, in&rared and 8ltra'iolet spetrometers, and an instr8ment alled a potopolarimeter are on a san plat&orm tat s(i'els on ommand so tese de'ie an be aimed at a tar)et (orld$ e spaera&t m8st kno( (ere Eart is i& te antenna is to be pointed properl and te data rereei'ed bak ome$ It also needs to kno( (ere te S8n is and at least one bri)t star, so it an orient itsel& in 50
tree dimensions and point properl to(ard an passin) (orld$ I& o8 anAt point te ameras, it does no )ood to be able to ret8rn pit8res o'er billions o& miles$ Ea spaera&t ost abo8t as m8 as a sin)le moder n strate)i bomber$ B8t 8nlik e bombers, Vo$ager annot, one la8ned, be ret8rned to te an)ar &or repairs$ e sipAs omp8ters and eletronis are tere&ore desi)ned red8ndantl$ 8 ke mainer, inl8din) te essential radio reei'er, ad at least one bak8pG(aitin) to be alled 8pon so8ld te o8r o& need e'er arri'e $ *en eiter Vo$ager &inds itsel& in tro8ble, te omp8ters 8se braned ontin)en tree lo)i to (ork o8t te appropriate o8rse o& ation$ I& tat doesnAt (ork, te sip radios ome &or elp$ s te spaera&t Ho8rnes inreasin)l &ar &rom Eart, te ro8ndtrip radio tra'el time also inreases, approain) ele'en o8rs b te time Vo$ager is at te distane o& Nept8ne$ 8s, in ase o& emer)en, te spaera&t needs to kno( o( to p8t itsel& into a sa&e standb mode (ile a(aitin) instr8tions &rom Eart$ s it a)es, more and more &ail8res are eCpeted, bot in its meanial parts and in its omp8ter sstem, alto8) tere is no si)n, e'en no(, o& a serio8s memor deterioration, some roboti leimerAs disease$ is is not to sa t at Vo$ager is per&et$ Serio8s mission-treatenin), (ite-kn8kle misaps did o8r$ Ea time, speial teams o& en)ineersGsome o& (om ad been (it te
Vo$ager pro)ram sine its ineptionG(ere assi)ned to (ork te problem$ e (o8ld st8d te 8nderlin) siene and dra( 8pon teir pre'io8s eCperiene (it te &ailed s8bsstems$ e (o8ld eCperiment (it idential Vo$ager spaera&t eK8ipment tat ad ne'er been la8ned, or e'en man8&at8re a lar)e n8mber o& omponents o& te sort tat &ailed in order to )ain some statistial 8nderstandin) o& te &ail8re mode$ In pril 197;, almost ei)t monts a&ter la8n, and (ile te sip (as approain) te asteroid belt, an omitted )ro8nd ommandGa 8man errorGa8sed Vo$ager 2s on-board omp8ter to s(it &rom te prim e radio reei'er to its bak8 p, !8rin) te neCt )ro8nd transmission to te spaera&t, te bak8p reei'er re&8sed to lok onto te si)nal &rom Eart$ omponent alled a trakin) loop apaitor ad &ailed$ &ter se'en das in (i Vo$ager 2 (as entirel o8t o& ontat, its &a8lt protetion so&t(are s8ddenl ommanded te bak8p reei'er to be s(ited o&& and te prime reei'er to be s(ited bak on$ sterio8slGto tis da, no one kno(s (Gte prime reei'er &ailed moments later$ It (as ne'er eard &rom a)ain$ o top it o&&, te on-board omp8ter no( &oolisl insisted on 8sin) te &ailed primar reei'er$ ro8) an 8nl8k onatenation o& 8man and roboti error, te spaera&t (as no( in real Heopard$ No one o8ld tink o& a (a to )et Vo$ager 2 to re'ert to te bak8p reei'er$ E'en i& it did, te bak8p reei'er o8ldnAt reei'e te ommands &rom Eart, bea8se o& tat &ailed apaitor$ ere (ere man proHet personnel (o &eared tat all (as lost$ B8t a&ter a (eek o& obd8rate 8nresponsi'eness to all ommands, instr8tions to s(it a8tomatiall bet(een reei'ers (ere aepted and pro)rammed into te skittis onboard omp8ter$ !8rin) tat same (eek te >. en)ineers desi)ned an inno'ati'e ommand &reK8en ontrol proed8re to make s8re tat essential orders (o8ld be 8nderstood b te dama)ed bak8p reei'er$
51
e en)ineers (ere no( able to reomm8niate, at least in a r8dimentar (a, (it te spaera&t$ n&ort8natel te bak8p reei'er no( t8rned )idd, beomin) eCtremel sensiti'e to stra eat d8mped (en 'ario8s omponents o& te spae ra&t po(ered 8p or do(n$ In te &ollo(in) monts te >. en)ineers de'ised and ond8ted tests tat let tem toro8)l 8nderstand te termal impliations o& most spaera&t operational modes: *at (o8ld pre'ent and (at (o8ld permit reeipt o& ommands &rom EartD *it tis in&ormation, te bak8p reei'er problem (as entirel ir8m'ented$ It s8bseK8entl aK8ired all te ommands sent &rom Eart on o( to )ater data in te >8piter, Sat8rn, ran8s, and Nept8ne sstems$ e en)ineers ad sa'ed te mission$ =o be on te sa&e side, d8rin) most o& Vo$ager 2 s8bseK8ent &li)t a nominal data-takin) seK8ene &or te neCt planet to be eno8ntered (as al(as sittin) in te on-board omp8tersGso8ld te spaera&t a)ain beome dea& to entreaties &rom ome$< noter eart-(renin) &ail8re o8rred H8st a&ter Vo$ager 2 emer)ed &rom beind Sat8rn =as seen &rom te Eart< in 8)8st 19;1$ e san plat&orm ad been mo'in) &e'erislG pointin) ere and tere amon) te rin)s, moons, and te planet itsel& d8rin) te all-too-brie& moments o& lose approa$ S8ddenl, te plat&orm Hammed$ st8k san plat&orm is a maddenin) prediament: kno(in) tat te spaera&t is &lin) past (onders tat a'e ne'er been (itnessed, tat (e (ill not see a)ain &or ears or deades, and te in8rio8s spaera&t starin) &iCedl o&& into spae, i)norin) e'ertin)$ e san plat&orm is dri'en b at8ators ontainin) )ear trains$ So &irst te >+. en)ineers ran an idential op o& a &li)t at8ator in a sim8lated mission$ is at8ator &ailed a&ter 34; t8rns? te at8ator on te spaera&t ad &ailed a&ter 35" t8rns$ e problem t8rned o8t to be a l8briation &ail8re$ /ood to kno(, b8t (at to do abo8t itD lainl, it (o8ld be impossible to o'ertake Vo$ager (it ail oilan$ e en)ineers (ondered (eter te o8ld restart te tailed at8ator b alternate eatin) and oolin)? mabe te res8ltin) termal stresses (o8ld ind8e te omponents o& te at8ator to eCpand and ontrat at di&&erent rates and 8nHam te sstem$ e tested tis notion (it speiall man8&at8red at8ators in te laborator, and ten H8bilantl &o8nd tat in tis (a te o8ld start te san plat&orm 8p a)ain in spae$ roHet personnel also de'ised (as to dia)nose an additional trend to(ard at8ator &ail8re earl eno8) to (ork aro8nd te problem$ erea&ter, Vo$ager 2As san plat&orm (orked per&etl$ ll te pit8res taken in te ran8s and Nept8ne sstems o(e teir eCistene to tis (ork$ e en)ineers ad sa'ed te da a)ain$
Vo$ager 1 and 2 (ere desi)ned to eCplore te >8piter and Sat8rn sstems onl$ It is tr8e tat teir traHetories (o8ld arr tem on past ran8s and Nept8ne, b8t o&&iiall tese planets (ere ne'er ontemplated as tar)ets &or Vo$ager eCploration: e spaera&t (ere not s8pposed to last tat lon)$ Bea8se o& o8r (is to &l lose to te mster (orld itan,
Vo$ager 9 (as
&l8n) b Sat8rn on a pat tat o8ld ne'er eno8nter an oter kno(n (orld? it is Vo$ager 2 tat &le( on to ran8s and Nept8ne (it brilliant s8ess$ t tese immense distanes, s8nli)t is )ettin) pro)ressi'el dimmer, and te radio si)nals transmitted to Eart are )ettin) pro)ressi'el &ainter$ ese (ere preditable b8t still 'er serio8s problem s tat te >. en)ineers and sientists also ad to sol'e$ 5"
Bea8se o& te lo( li)t le'el s at ran8s and Nept8ne, te Vo$ager tele'ision ameras (ere obli)ed to take lon) time eCpos8res$ B8t te spaera&t (as 8rtlin) so &ast tro8), sa, te ran8s sstem =at abo8t 35,000 miles per o8r< tat te ima)e (o8ld a'e been smeared or bl8rred$ o ompensate, te entire spaera&t ad to be mo'ed d8rin) te time eCpos8res to anel o8t te motion, like pannin) in te diretion opposite o8rs (ile takin) a poto)rap o& a street sene &rom a mo'in) ar$ is ma so8nd eas, b8t itAs not: o8 a'e to ne8tralie te most innoent o& motions$ t ero )ra'it, te mere start and stop o& te on-board tape reorder an Hi))le te spaera&t eno8) to smear te pit8re$ is problem (as sol'ed b sendin) 8p ommands to te spaera&tAs little roket en)ines =alled tr8sters<, maines o& eCK8isite sensiti'it$ *it a little p8&& o& )as at te start and stop o& ea data-takin) seK8ene, te tr8sters ompensated &or te tape-reorder Hi))le b t8rnin) te entire spaera&t H8st a little$ o deal (it te lo( radio po(er reei'ed at Eart, te en)ineers de'ised a ne( and more e&&iient (a to reord and transmit te data, and te radio telesopes on Eart (ere eletroniall linked to)eter (it oters to inrease teir sensiti'it$ 2'erall, te ima)in) sstem (orked, b man riteria, better at ran8s and Nept8ne tan it did at Sat8rn or e'en at >8piter$
Vo$ager ma not et be done eCplorin)$ ere is, o& o8rse, a ane tat some 'ital s8bsstem (ill &ail tomorro(, b8t as &ar as te radioati'e dea o& te pl8toni8m po(er so8re is onerned, te t(o Vo$ager spaera&t so8ld be able to ret8rn data to Eart ro8)l tro8) te ear "015$
Vo$ager is an intelli)ent bein)Gpart robot, part 8man$ It eCtends te 8man senses to &aro&& (orlds$ %or simple tasks and sort-term problems, it relies on its o(n intelli)ene? b8t &or more ompleC tasks and lon)er-term problems, it t8rns to te olleti'e intelli)ene and eCperiene o& te >. en)ineers$ is trend is s8re to )ro($ e Vo$ager embod te tenolo) o& te earl 1970s? i& spaera&t (ere desi)ned &or s8 a mission toda, te (o8ld inorporate st8nnin) ad'anes in arti&iial intelli)ene, in miniat8riation, in data-proessin) speed, in te abilit to sel&-dia)nose and repair, and in te propensit to learn &rom eCperiene e (o8ld also be m8 eaper$ In te man en'ironments too dan)ero8s &or people, on Eart as (ell as in spae, te &8t8re belon)s to robot-8man partnersips tat (ill reo)nie te t(o Vo$ager as anteedents and pioneers$ %or n8lear aidents, mine disasters, 8ndersea eCploration and araeolo), man8&at8rin), pro(lin) te interiors o& 'olanos, and o8seold elp, to name onl a &e( potential appliations, it o8ld make an enormo8s di&&erene to a'e a read orps o& smart, mobile, ompat, ommandable robots tat an dia)nose and repair teir o(n mal&8ntions$ ere are likel to be man more o& tis tribe in te near &8t8re$ It is on'entional (isdom no( tat antin) b8ilt b te )o'ernment (ill be a disaster$ B8t te t(o Vo$ager spaera&t (ere b8ilt b te )o'ernment =in partnersip (it tat oter b8)aboo, aademia<$ e ame in at ost, on time, and 'astl eCeeded teir desi)n spei&iationsGas (ell as te &ondest dreams o& teir makers$ Seekin) not to ontrol, treaten, (o8nd, or destro, tese ele)ant maines represent te eCplorator part o& o8r nat8re set &ree to roam te Solar Sstem and beond$ is kind o& tenolo), te treas8res it 8no'ers &reel 53
a'ailable to all 8mans e'er(ere, as been, o'er te last &e( deades, one o& te &e( ati'ities o& te nited States admired as m8 b tose (o abor man o& its poliies as b tose (o a)ree (it it on e'er iss8e$ Vo$ager ost ea merian less tan a penn a ear &rom la8n to Nept8ne eno8nter$ issions to te planets are one o& tose tin)sGand I mean tis not H8st &or te nited States, b8t &or te 8man speiesGtat (e do best$
C
H
A
P
54
T
E
R
7
2N/ E 22NS 2% SN Seat tsel& s8ltaniall amon) te moons o& Sat8rn$
GEN E.#I..E, MO>, .!#D +E 107 =1;51<
Tere is a (orld, mid(a in sie bet(een te oon and ars, (ere te 8pper air is ripplin) (it eletriitGstreamin) in &rom te aretpial rin)ed planet neCt door, (ere te perpet8al bro(n o'erast is tin)ed (it an odd b8rnt oran)e, and (ere te 'er st8&& o& li&e &alls o8t o& te skies onto te 8nkno(n s8r&ae belo($ It is so &ar a(a tat li)t takes more tan an o8r to )et tere &rom te S8n$ Spaera&t take ears$ 8 abo8t it is still a msterGinl8din) (eter it olds )reat oeans$ *e kno( H8st eno8), to8), to reo)nie tat (itin rea ma be a plae (ere ertain proesses ate toda (orkin) temsel'es o8t tat aeons a)o on Eart led to te ori)in o& li&e$ 2n o8r o(n (orld a lon)-standin)Gand in some respets K8ite promisin)GeCperiment as been 8nder (a on te e'ol8tion o& matter$ e oldest kno(n &ossils are abo8t 3$6 billion ears old$ 2& o8rse, te ori)in o& li&e ad to a'e appened (ell be&ore tat$ B8t 4$" or 4$3 billion ears a)o te Eart (as bein) so ra'a)ed b te &inal sta)es o& its &ormation tat li&e o8ld not et a'e ome into bein): assi'e ollisions (ere meltin) te s8r&ae, t8rnin) te oeans into steam and dri'in) an atmospere tat ad a8m8lated sine te last impat o&& into spae$ So aro8nd 4 billion ears a)o, tere (as a &airl narro( (indo(Gperaps onl a 8ndred million ears (ide in (i o8r most distant anestors ame to be$ 2ne onditions permitted, li&e arose
55
&ast$ Someo($ e &irst li'in) tin)s 'er likel (ere inept, &ar less apable tan te most 8mble mirobe ali'e todaGperaps H8st barel able to make r8de opies o& temsel'es$ B8t nat8ral seletion, te ke proess &irst oerentl desribed b +arles !ar(in, is an instr8ment o& s8 enormo8s po(er tat &rom te most modest be)innin)s tere an emer)e all te riness and bea8t o& te biolo)ial (orld$ ose &irst li'in) tin)s (ere made o& piees, parts, b8ildin) bloks (i ad to ome into bein) on teir o(nGtat is, dri'en b te la(s o& psis and emistr on a li&eless Eart$ e b8ildin) bloks o& all terrestrial li&e are alled or)ani mole8les, mole8les based on arbon$ 2& te st8pendo8s Rl8mber o& possible or)ani mole8les, 'er &e( are 8sed at te eart o& li&e$ e t(o most important lass es are te amino aids, te b8ildin) bloks o& proteins, and te n8leotide bases, te b8ildin) bloks o& te n8lei aids$ ist be&ore te ori)in o& li&e, (ere did tese mole8les ome &romD ere are onl t(o possibilities: &rom te o8tside or &rom te inside$ *e kno( tat 'astl more omets and asteroids (ere ittin) te Eart tan do so toda, tat tese small (orlds are ri storeo8ses o& ompleC or)ani mole8les, and tat some o& tese mole8les esaped bein) &ried on impat$ ere IAm desribin) omemade, not imported, )oods: te or)ani mole8les )enerated in te air and (aters o& te primiti'e Eart$ n&ort8natel, (e donAt kno( 'er m8 abo8t te omposition o& te earl air, and or)ani mole8les are &ar easier to make in some atmosperes tan in oters$ ere o8ldnAt a'e been m8 oC)en, bea8se oC)en is )enerated b )reen plants and tere (erenAt an )reen plants et$ ere (as probabl more dro)en, bea8se dro)en is 'er ab8ndant in te ni'erse and esapes &rom te 8pper atmospere o& te Eart into spae better tan an oter atom =bea8se itAs so li)t<$ I& (e an ima)ine 'ario8s possible earl atmosperes, (e an d8pliate tem in te laborator, s8ppl some ener), and see (i or)ani mole8les are made and in (at amo8nts$ S8 eCperiments a'e o'er te ears pro'ed pro'oati'e and promisin)$ B8t o8r i)norane o& initial onditions limits teir rele'ane$ *at (e need is a real (orld (ose atmospere still retains some o& tose dro)en-ri )ases, a (orld in oter respets sometin) like te Eart, a (orld in (i te or)ani b8ildin) bloks o& li&e are bein) massi'el )enerated in o8r o(n time, a (orld (e an )o to to seek o8r o(n be)innin)s$ ere is onl one s8 (orld in te Solar Sstem$ 1 at (orld is itan, te bi) moon o& Sat8rn$ ItAs abo8t 5,150 kilometers =3,"00 miles< in diameter, a little less tan al& te sie o& te Eart$ It takes 16 o& o8r das to omplete one orbit o& Sat8rn$ No (orld is a per&et replia o& an oter, and in at least one important respet itan is 'er di&&erent &rom te primiti'e Eart: Bein) so &ar &rom te S8n, its s8r&ae is eCtremel old, &ar belo( te &reein) point o& (ater, aro8nd 1;0U belo( ero +elsi8s$ So (ile te Eart at te time o& te ori)in o& li&e (as, as no(, mainl oean-o'ered, plainl tere an be no oeans o& liK8id (ater on itan$ =2eans made o& oter st8&& are a di&&erent stor, as (e sall see$< e lo( temperat8res pro'ide an ad'anta)e, to8), bea8se one mole8les are sntesied on itan, te tend to stik aro8nd: e i)er te temperat8re, te &aster mole8les &all to piees$ 2n 1
ere o8ld a'e been none$ *eAre 'er l8k tat tere is s8 a (orld st8d$ e oters ill a'e too m8 dro)en, or not eno8), or no atmospere at all$
56
itan te mole8les tat a'e been rainin) do(n like manna &rom ea'en &or te last 4 billion ears mi)t still be tere, lar)el 8naltered, deep-&roen, a(aitin) te emists &rom Eart$ THE INVENTION OF THE TELESCOPE In
te se'enteent ent8r led to te diso'er o& man ne(
(orlds$ In 1610 /alileo &irst spied te &o8r lar)e satellites o& >8piter$ It looked like a miniat8re solar sstem, te little moons rain) aro8nd >8piter as te planets (ere to8)t b +operni8s to orbit te S8n$ It (as anoter blo( to te )eoentrists$ %ort-&i'e ears later, te elebrated !8t psiist +ristian8s 8)ens diso'ered a moon mo'in) abo8t te planet Sat8rn and named it itan$1 It (as a dot o& li)t a billion miles a(a, )leamin) in re&leted s8nli)t$ %rom te time o& its diso'er, (en E8ropean men (ore lon) 8rl (i)s, to (orld *ar II, (en merian men 8t teir air do(n to st8bble, almost notin) more (as diso'ered abo8t itan eCept te &at it ad a 8rio8s, ta(n olor$ /ro8nd-based telesopes o8ld, e'en in priniple, barel make o8t some eni)mati detail$ e Spanis astronomer >$ +omas Sola reported at te t8rn o& te t(entiet ent8r some &aint and indiret e'idene o& an atmospere$ In a (a, I )re( 8p (it itan$ I did m dotoral dissertation at te ni'ersit o& +ia)o 8nder te )8idane o& /erard $ 8iper, te astronomer (o made te de&initi'e diso'er tat itan as an atmospere$ 8iper (as !8t and in a diret line o& intellet8al desent &rom +ristian8s 8)ens$ In 1914, (ile makin) a spetrosopi eCamination o& itan, 8iper (as astonised to &ind te arateristi spetral &eat8res o& te )as metane$ *en e pointed te telesope at itan, tere (as te si)nat8re o& metane$ " *en e pointed it a(a, not a int o& metane$ B8t moons (ere not s8pposed to old onto siable atmosperes, and te EartAs oon ertainl doesnAt$ itan o8ld retain an atmospere, 8iper realied, e'en to8) its )ra'it (as less tan EartAs, bea8se its 8pper atmospere is 'er old$ e mole8les simpl arenAt mo'in) &ast eno8) &or si)ni&iant n8mbers to aie'e esape 'eloit and trikle a(a to spae$ !aniel arris, a st8dent o& 8iperAs, so(ed de&initi'el tat itan is red$ abe (e (ere lookin) at a r8st s8r&ae, like tat o& ars$ I& o8 (anted to learn more abo8t itan, o8 o8ld also meas8re te polariation o& s8nli)t re&leted o&& it$ 2rdinar s8nli)t is 8npolaried$ >osep #e'erka, no( a &ello( &a8lt member at +ornell ni'ersit, (as m )rad8ate st8dent at ar'ard ni'ersit, and tere&ore, so to speak, a )randst8dent o& 8iperAs$ In is dotoral (ork, aro8nd 1970, e meas8red te polariation o& itan and &o8nd tat it an)ed as te relati'e positions o& itan, te S8n, and te Eart an)ed$ B8t te an)e (as 'er di&&erent &rom tat eCibited b, sa, te oon$ #e'erka onl8ded tat te arater o& tis 'ariation (as onsistent (it eCtensi'e lo8ds or ae on itan$ *en (e looked at it tro8) te telesope, (e (erenAt seein) its s8r&ae$ *e kne( notin) abo8t (at te s8r&ae (as like$ *e ad no idea o( &at belo( te lo8ds te s8r&ae (as$ So, b te earl 1970s, as a kind o& le)a &rom 8)ens and is line o& intellet8al desent, (e kne( at least tat itan as a dense metane-ri atmospere, and tat itAs probable en'eloped 1
Not bea8se e to8)t it remarkabl lar)e$ b8t bea8se in /reek mtolo) members o& te )eneration preedin) te 2lmpian )odsGSat8rn, is siblin)s, and is o8sinsG(ere alled itans$ "
itanAs atmospere as no detetable oC)en, so metane is not (ildl o8t o& emial eK8ilibri8mGas it is on EartGand its presene is in no (a a si)n o& li&e
57
b a reddis lo8d 'eil or aerosol ae$ B8t (at kind o& lo8d is redD B te earl 1970s m ollea)8e Bis8n are and I ad been doin) eCperiments at +ornell in (i (e irradiated 'ario8s metane-ri atmosperes (it ltra'iolet li)t or eletrons and (ere )eneratin) reddis or bro(nis solids? te st8&& (o8ld oat te interiors o& o8r reation 'essels$ It seemed to me tat, i& metane-ri itan ad red-bro(n lo8ds, tose lo8ds mi)t 'er (ell be similar to (at (e (ere makin) in te laborator$ *e alled tis material tolin, a&ter a /reek (ord &or m8dd$ t te be)innin) (e ad en little idea (at it (as made o&$ It (as some or)ani ste( made b breakin) apart o8r startin) mole8les, and allo(in) te atomsGarbon, dro)en, nitro)enGand mole8lar &ra)ments to reombine$ e (ord or)ani arries no imp8tation o& biolo)ial ori)in? &ollo(in) lon)-standin) emial 8sa)e datin) bak mots tan a ent8r, it merel desribes mole8les b8ilt o8t o& ar bon atoms =eCl8din) a &e( 'er simple ones s8 as arbon monoCide, +2, and arbon dioCide, +2"<$ Sine li&e on Eart is based oil or)ani mole8les, and sine tere (as a time be&ore "ere
Vo$ager 1 and 2 spaera&t in te Sat8rn sstem$ e 8ltra'iolet, in&rared, and radio instr8ments re'ealed te press8re and temperat8re tro8) te atmospereG&rom te idden s8r&ae to te ed)e o& spae$ *e learned o( i) te lo8d tops are$ *e &o8nd tat te air on itan is omposed mainl o& nitro)en, N ", as on te Eart toda$ e oter prinipal onstit8ent is, as 8iper &o8nd, metane$ + 4 te startin) material &rom (i arbon-based or)ani mole8les are )enerated tere$ 'ariet o& simple or)ani mole8les (as &o8nd, present as )ases, mainl droarbons and nitriles$ e most ompleC o& tem a'e &o8r ea' =arbon andor nitro)en< atoms$ droarbons are mole8les omposed o& arbon and dro)en atoms onl, and are &amiliar to 8s as nat8ral )as, petrole8m, and (aCes$ =eAre K8ite di&&erent &rom arbodrates, s8 as s8)ars and star, (i also a'e oC)en atoms$< Nitriles are mole8les (it a arbon and nitro)en atom attaed in a parti8lar (a$ e best kno(n nitrile is +N, dro)en anide, a deadl )as &or 8mans$ B8t dro)en anide is impliated in te steps tat on Eart led to te ori)in o& li&e$ %indin) tese simple or)ani mole8les in itanAs 8pper atmospereGe'en i& present onl in a part per million or a part per billionGis tantaliin)$ +o8ld te atmospere o& te prime'al Eart a'e been similarD ereAs abo8t ten times more air oil itan tan tere is on Eart toda, b8t te earl Eart ma (ell a'e ad a denser atmospere$ oreo'er, Vo$ager diso'ered an eCtensi'e re)ion o& ener)eti eletrons and protons s8rro8ndin) Sat8rn, trapped b te planetAs ma)neti &ield$ !8rin) te o8rse o& its orbital motion aro8nd Sat8rn, itan bobs in and o8t o& tis ma)netospere$ Beams o& eletrons =pl8s solar 8ltra'iolet li)t< &all on te 8pper air o& itan, H8st as ar)ed partiles =pl8s solar 8ltra'iolet li)t< (ere interepted b te atmospere o& te primiti'e Eart$
5;
So itAs a nat8ral to8)t to irradiate te appropriate miCt8re o& nitro)en and metane (it 8ltra'iolet li)t or eletrons at 'er lo( press8res, and &ind o8t (at more ompleC mole8les an be made$ +an (e sim8late (atAs )oin) on in itanAs i) atmospereD In o8r laborator at +ornellG(it m ollea)8e *$ eid ompson plain) a ke roleG(eA'e repliated some o& itanAs man8&at8re o& or)ani )ases$ e simplest droarbons on itan are man8&at8red b 8ltra'iolet li)t &rom te S8n$ B8t &or all
te oter )as prod8ts, tose made most readil b
eletrons in te laborator orrespond to tose diso'ered b Vo$ager on itan, and in te same proportions$ e orrespondene is one to one$ e neCt most ab8ndant )ases tat (eA'e &o8nd in te laborator (ill be looked &or in &8t8re st8dies o& itan$ e most ompleC or)ani )ases (e make a'e siC or se'en arbon andor nitro)en atoms$ ese prod8t mole8les are on teir (a to &ormin) tolins$
WE HAD HOPED FOR A BREAKIn
te (eater as Vo$ager 1 approaed itan$ lon) distane
a(a, it appeared as a tin disk? at losest approa, o8r ameraAs &ield o& 'ie( (as &illed b a small pro'ine o& itan$ I& tere ad been a break in te ae and lo8ds, e'en onl a &e( miles aross, as (e sanned te disk (e (o8ld a'e seen sometin) o& its idden s8r&ae$ B8t tere (as no int o& a break$ is (orld is soked in$ No one on Eart kno(s (atAs on itanAs s8r&ae$ nd an obser'er tere, lookin) 8p ill ordinar 'isible li)t, (o8ld a'e no idea o& te )lories tat a(ait 8pon asendin) tro8) te ae and beoldin) Sat8rn and its ma)ni&ient rin)s$ %rom meas8rements b Vo$ager b te !n"erna"ional l"ra4iole" Explorer obser'ator in Eart orbit, and b )ro8nd-based telesopes, (e kno( a &air amo8nt abo8t te oran)e-bro(n ae partiles tat obs8re te s8r&ae: (i olors o& li)t te like to absorb, (i olors te prett m8 let pass tro8) tem, o( m8 te bend, te li)t tat does pass tro8) tem, and o( bi) te are$ =eAre mostl te sie o& te partiles in i)arette smoke$< e optial properties (ill depend, o& o8rse, on te omposition o& te ae partiles$ In ollaboration (it Ed(ard raka(a o& 2ak id)e National .aborator in ennessee, are and I a'e meas8red te optial properties o& itan tolin$ It t8rns o8t to be a dead rin)er &or te real itan ae$ No oter andidate material, mineral or or)ani, mates te optial onstants o& itan$ So (e an &airl laim to a'e bottled te ae o& itanG&ormed i) in its atmospere, slo(l &allin) o8t, and a8m8latin) in opio8s amo8nts on its s8r&ae$ *at is tis st8&& made o&D ItAs 'er ard to kno( te eCat omposition o& a ompleC or)ani solid$ %or eCample, te emistr o& oal is still not &8ll 8nderstood, despite a lon)-standin) eonomi inenti'e$ B8t (eA'e &o8nd o8t some tin)s abo8t itan tolin$ It ontains man o& te essential b8ildin) bloks o& li&e on Eart$ Indeed, i& o8 drop itan tolin into (ater o8 make a lar)e n8mber o& amino aids, te &8ndamental onstit8ents o& proteins, and n8leotide bases also, te b8ildin) bloks o& !N and N$ Some o& te amino aids so &ormed are (idespread in li'in) tin)s on Eart$ 2ters are o& a ompletel di&&erent sort$ ri arra o& oter or)ani mole8les is present also, some rele'ant to li&e, some not$ !8rin) te past &o8r billion ears, immense K8antities o& or)ani mole8les sedimented o8t o& te atmospere onto te s8r&ae o& itan$ I& itAs all deep-&roen and
59
8nan)ed in te inter'enin) aeons, te amo8nt a8m8lated so8ld be at least tens o& meters =a 8ndred &eet< tik? o8tside estimates p8t it at a kilometer deep$ B8t at 1;0U+ belo( te &reein) point o& (ater, o8 mi)t 'er (ell tink tat amino aids (ill ne'er be made$ !roppin) tolins into (ater ma be rele'ant to te earl Eart, b8t not, it (o8ld seem, to itan$ o(e'er, omets and asteroids m8st on oasion ome rasin) into te s8r&ae o& itan$ =e oter nearb moons o& Sat8rn so( ab8ndant impat raters, and te atmospere o& itan isnAt tik eno8) to pre'ent lar)e, i)-speed obHets &rom reain) te s8r&ae$< lto8) (eA'e ne'er seen te s8r&ae o& itan, planetar sientists ne'erteless kno( sometin) abo8t its omposition$ e a'era)e densit o& itan lies bet(een te densit o& ie and te densit o& rok$ la8sibl it ontains bot$ Ie and rok are ab8ndant on nearb (orlds, some o& (i are made o& nearl p8re rie$ I& te s8r&ae o& itan is i, a i)-speed ometar impat (ill temporaril melt te ie$ ompson and I estimate tat an )i'en spot on itanAs s8r&ae as a better tan 50-50 ane o& a'in) one been melted, (it an a'era)e li&etime o& te impat melt and sl8rr o& almost a to8sand ears$ is makes &or a 'er di&&erent stor$ e ori)in o& li&e on Eart seems to a'e o8rred in oeans and sallo( tidepools$ .i&e on Eart is made mainl o& (ater, (i plas an essential psial and emial role$ Indeed, itAs ard, &or 8s (ater-besotted reat8res to ima)ine li&e (ito8t (ater$ I& on o8r planet te ori)in o& li&e took less tan a 8ndred million ears, is tere an ane tat on itan it took a to8sandD *it tolins miCed into liK8id (ater-e'en &or onl a to8sand ears te s8r&ae o& itan ma be m8 &8rter alon) to(ard te ori)in o& li&e tan (e to8)t$ DESPITE ALL THIS(e
8nderstand piti&8ll little abo8t itan$ is (as bro8)t ome &ore&8ll to
me at a sienti&i smposi8m on itan eld in o8lo8se, %rane, and sponsored b te E8ropean Spae )en =ES<$ *ile oeans o& liK8id (ater are impossible on itan, oeans o& liK8id droarbons are not$ +lo8ds o& metane =+ 4<, te most ab8ndant droarbon, are eCpeted not &ar abo'e te s8r&ae$ Etane =+ "6<, te neCt most ab8ndant droarbon, m8st ondense o8t at te s8r&ae in te same (a tat (ater 'apor beomes a liK8id near te s8r&ae o& te Eart, (ere te temperat8re is )enerall bet(een te &reein) and meltin) points$ #ast oeans o& liK8id droarbons so8ld a'e a8m8lated o'er te li&etime o& itan$ e (o8ld lie &ar beneat te ae and lo8ds$ B8t tat doesnAt mean te (o8ld be (oll inaessible to 8sG bea8se radio (a'es readil penetrate te atmospere o& itan and its s8spended, slo(l &allin) &ine partiles$ In o8lo8se, !8ane 2$ 8leman o& te +ali&ornia Instit8te o& enolo) desribed to 8s te 'er di&&i8lt tenial &eat o& transmittin) a set o& radio p8lses &rom a radio telesope in +ali&orniaAs oHa'e !esert, so te rea itan, penetrate tro8) te ae and lo8ds to its s8r&ae, are re&leted bak into spae, and ten ret8rned to Eart$ ere, te )reatl en&eebled si)nal is piked 8p b an arra o& radio telesopes near Soorro, Ne( eCio$ /reat$ I& itan as a rok or i s8r&ae, a radar p8lse re&leted o&& its s8r&ae so8ld be detetable on Eart$ B8t i& itan (ere o'ered (it droarbon oeans, 8leman so8ldnAt see a tin): .iK8id droarbons are blak to tese radio (a'es, and no eo (o8ld a'e been ret8rned to Eart$ In 60
&at, 8lemanAs )iant radar sstem sees a re&letion (en some lon)it8des o& itan are t8rned to(ard Eart, and not at oter lon)it8des$ ll ri)t, o8 mi)t sa, so itan as oeans and ontinents, and it (as a ontinent tat re&leted te si)nals bak to Eart$ B8t i& itani in tis respet like te EartG&or some meridians =tro8) E8rope and &ria, sa< mainl ontinent, and &or oters =tro8) te entral ai&i, sa< mainl oeanGten (e m8st on&ront anoter problem: e orbit o& itan aro8nd Sat8rn is not a per&et irle$ itAs notieabl sK8ased o8t, or elliptial$ I& itan as eCtensi'e oeans, to8), te )iant planet Sat8rn aro8nd (i it orbits (ill raise s8bstantial tides on itan, and te res8ltin) tidal &rition (ill ir8larie itanAs orbit in m8 less tan te a)e o& te Solar Sstem$ In a 19;" sienti&i paper alled e ide in te Seas o& itan, Stanle !ermott, no( at te ni'ersit o& %lorida, and I ar)8ed tat &or tis reason itan m8st be eiter an all-oean or an all-land (orld$ 2ter(ise te tidal &rition in plaes (ere te oean is sallo( (o8ld a'e taken its toll$ .akes and islands mi)t be permitted, b8t antin) more and itan (o8ld a'e a 'er di&&erent orbit tan te one (e see$ *e a'e, ten, tree sienti&i ar)8mentsGone onl8din) tat tis (orld is almost entirel o'ered (it droarbon oeans, anoter tat itAs a miC o& ontinents and oeans, and a tird reK8irin) 8s to oose, o8nselin) tat itan anAt a'e eCtensi'e oeans and eCtensi'e ontinents at te same time$ It (ill be interestin) to see (at te ans(er t8rns o8t to be$ *at IA'e H8st told o8 is a kind o& sienti&i pro)ress report$ omorro( tere mi)t be a ne( &indin) tat lears 8p tese msteries and ontraditions$ abe tereAs sometin) (ron) (it 8lemanAs radar res8lts, alto8) itAs ard to see (at it mi)t be: is sstem tells im eAs seein) itan (en itAs nearest, (en e o8)t to be seein) itan$ abe tereAs sometin) (ron) (it !ermottAs and m al8lation abo8t te tidal e'ol8tion o& te orbit o& itan, b8t no one as been able to &ind an errors so &ar$ nd itAs Bard to see o( etane an a'oid ondensin) o8t at te s8r&ae o& itan$ abe, despite te lo( temperat8res, o'er billions o& ears tereAs been a an)e in te emistr? mabe some ombination o& omets impatin) &rom te sk and 'olanoes and oter tetoni e'ents, elped alon) b osmi ras, an on)eal liK8id droarbons, t8rnin) tem into some ompleC or)ani solid tat re&lets radio (a'es bak to spae$ 2r mabe sometin) re&leti'e to radio (a'es is &loatin) on te oean s8r&ae$ B8t liK8id droarbons are 'er 8nderdense: E'er kno(n or)ani solid, 8nless eCtremel &rot, (o8ld sink like a stone in te seas o& itan$ !ermott and I no( (onder (eter, (en (e ima)ined ontinents and oeans on itan, (e (ere too trans&iCed b o8r eCperiene on o8r o(n (orld, too Eart-a8'inist in o8r tinkin)$ Battered, ratered terrain and ab8ndant impat basins o'er oter moons in te Sat8rn sstem$ I& (e pit8red liK8id droarbons slo(l a8m8latin) on one o& tose (orlds, (e (o8ld (ind 8p not (it )lobal oeans, b8t (it isolated lar)e raters &illed, alto8) not to te brim, (it liK8id droarbons$ an ir8lar seas o& petrole8m, some o'er a 8ndred miles aross, (o8ld be splattered aross te s8r&aeGb8t no pereptible (a'es (o8ld be stim8lated b distant Sat8rn and, it is on'entional to tink, no sips, no s(immers, no s8r&ers, and no &isin)$ idal &rition so8ld, (e al8late, be ne)li)ible in s8 a ase, and itanAs streted-o8t, elliptial orbit (o8ld not a'e beome so ir8lar$ *e anAt kno( &or s8re 8ntil (e start )ettin) radar or near-in&rared 61
ima)es o& te s8r&ae$ B8t peraps tis is te resol8tion o& o8r dilemma: itan as a (orld o& lar)e ir8lar droarbon lakes, more o& tem in some lon)it8des tan in oters$ So8ld (e eCpet an i s8r&ae o'ered (it deep tolin sediments, a droarbon oean (it at most a &e( or)ani enr8sted islands pokin) 8p ere and tere, a (orld o& rater lakes, or sometin) more s8btle tat (e a'enAt et &i)8red o8tD is isnAt H8st an aademi K8estion, bea8se tereAs a real spaera&t bein) desi)ned to )o to itan$ In a Hoint NSES pro)ram, a spaera&t alled +assini (ill be la8ned in 2tober 1997Gi& all )oes (ell$ *it t(o &lbs o& #en8s, one o& Eart, and one o& >8piter &or )ra'itational assists, te sip (ill, a&ter a se'en-ear 'oa)e, be inHeted into orbit aro8nd Sat8rn$ Ea time te spaera&t omes lose to itan, te moon (ill be eCamined b an arra o& instr8ments, inl8din) radar$ Bea8se +assini (ill be so m8 loser to itan, it (ill be able to resol'e man details on itanAs s8r&ae indetetable to 8lemanAs pioneerin) Eart-based sstem$ ItAs also likel tat te s8r&ae an be 'ie(ed in te near in&rared$ aps o& te idden s8r&ae o& itan ma be in o8r ands sometime in te s8mmer o& "004$ +assini is also arrin) an entr probe, &ittin)l alled u$gen (i (ill deta itsel& &rom te main spaera&t and pl8mmet into itanAs atmospere$ )reat para8 te (ill be deploed$ e instr8ment paka)e (ill slo(l settle tro8) te or)ani ae do(n into te lo(er atmospere, tro8) te metane lo8ds$ It (ill eCamine or)ani emistr as it desends, andGi& it s8r'i'es te landin)Gon te s8r&ae o& tis (orld as (ell$ Notin) is )8aranteed$ B8t te mission is teniall &easible, ard(are is bein) b8ilt, an impressi'e oterie o& speialists, inl8din) man o8n) E8ropean sientists, are ard at (ork on it, and all te nations responsible seem ommitted to te proHet$ eraps it (ill at8all ome abo8t$ eraps (in)in) aross te billion miles o& inter'enin) interplanetar spae (ill be, in te not too distant &8t8re$ ne(s abo8t o( &ar alon) te pat to li&e itan as ome$
6"
C
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A
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T
E
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8
E %IS NE* .NE 1 implore $ou $ou o no" ope "o ;e a;le "o gi4e "e reaon or "e num;er o plane" o $ou is (orr as been resol'ed $ $ $ — >2NNES E.E, EP!/OME O #OPE!#A AS/OOM, B22 4 16"1
63
Be&ore (e in'ented i'iliation, o8r anestors li'ed mainl in te open, o8t 8nder te sk$ Be&ore (e de'ised arti&iial li)ts and atmosperi poll8tion and modern &orms o& not8rnal entertainment, (e (ated te stars$ ere (ere pratial alendrial reasons, o& o8rse, b8t tere (as more to it tan tat$ E'en toda, te most Haded it d(eller an be 8neCpetedl mo'ed 8pon eno8nterin) a lear ni)t sk st8dded (it to8sands o& t(inklin) stars$ *en it appens to me a&ter all tese ears, it still takes m breat a(a$ In e'er 8lt8re, te sk and te reli)io8s imp8lse are intert(ined$ I lie bak in an open &ield and te sk s8rro8nd me$ IAm o'erpo(ered b its sale$ ItAs so 'ast and so &ar a(a tat m o(n insi)ni&iane beomes palpable$ B8t I donAt &eel reHeted b te sk$ IAm a part o& it, tin, to be s8re, b8t e'ertin) is tin ompared to tat o'er(elmin) immensit, nd (en I onentrate on te stars, te planets, and teir motions, I a'e an irresistible sense o& mainer, lok(ork, ele)ant preision (orkin) on a sale tat, o(e'er lo&t o8r aspirations, d(ar&s and 8mbles 8s$ ost o& te )reat in'entions in 8man istorG&rom stone tools and te domestiation o& &ire to (ritten lan)8a)eG(ere made b 8nkno(n bene&ators$ 28r instit8tional memor o& lon))one e'ents is &eeble$ *e do not kno( te name o& tat anestor (o &irst noted tat planets (ere di&&erent &rom stars$ Se or e m8st a'e li'ed tens, peraps e'en 8ndreds o& to8sands o& ears a)o$ B8t e'ent8all people all o'er te (orld 8nderstood tat &i'e, no more, o& te bri)t points o& li)t tat )rae te ni)t sk break lokstep (it te oters o'er a period o& monts, mo'in) stran)el-almost as i& te ad minds o& teir o(n$ Sarin) te odd apparent motion o& tese planets (ere te S8n and oon, makin) se'en (anderin) bodies in all$ ese se'en (ere important to te anients, and te named tem a&ter )ods not an old )ods, b8t te main )ods, te ie& )ods, te ones (o tell oter )ods =and mortals< (at to do$ 2ne o& te planets, bri)t and slo(-mo'in), (as named b te Bablonians a&ter ard8k, b te Norse a&ter 2din, b te /reeks a&ter @e8s, and b te omans a&ter >8piter, in ea ase te kin) o& te )ods$ e &aint, &ast-mo'in) one tat (as ne'er &ar &rom te S8n te omans named er8r, a&ter te messen)er o& te )ods? te most brilliant o& tem (as named #en8s, a&ter te )oddess o& lo'e and bea8t? te blood red one ars, a&ter te )od o& (ar? and te most sl8))is o& te b8n Sat8rn, a&ter te )od o& time$ ese metapors and all8sions (ere te best o8r anestors o8ld do: e possessed no sienti&i instr8ments beond te naked ee, te (ere on&ined to te Eart, and te ad no idea tat it, too, is a planet$ 1 *en it )ot to be time to desi)n te (eekGa period o& time, 8nlike te da, mont, and ear, (it no intrinsi astronomial si)ni&ianeGit (as assi)ned se'en das, ea named a&ter one o& 1
ere (as one moment in te last 4,000 ears (en all se'en o& tese elestial bodies (ere l8stered ti)tl to)eter$ >8st be&ore da(n on ar 4, 1953 B$+$, te resent oon (as at te orion$ #en8s, er8r, ars, Sat8rn, and >8piter (ere str8n) o8t like He(els on a neklae near te )reat sK8are in te onstellation e)as8sGnear te spot &rom (i in o8r time te erseid meteor so(er emanates$ E'en as8al (aters o& te sk m8st a'e been trans&iCed b te e'ent$ *at (as itGa omm8nion o& te )odsD ordin) to te astronomer !a'id ankenier o& .ei) ni'ersit and later e'in an) o& >., tis e'ent (as te startin) point &or te planetar les o& te anient +inese astronomers$ ere is no oter time in te last 4,000 ears =or in te neCt< (en te dane o& te planets aro8nd te S8n brin)s tem so lose to)eter &rom te 'anta)e point o& Eart$ B8t on a 5, "000, all se'en (ill be 'isible in te same part o& te skGalto8) some at da(n and some at d8sk and abo8t ten times more spread o8t tan on tat late (inter mornin) in 1953 B$+$ Still, itAs robabl a)ood ni)t &or a part$
64
te se'en anomalo8s li)ts in te ni)t sk$ *e an readil make o8t te remnants o& tis on'ention$ In En)lis, Sat8rda is Sat8rnAs da$ S8nda and oQoRnda are lear eno8)$ 8esda tro8) %rida are named a&ter te )ods o& te SaCon and kindred e8toni in'aders o& +eltioman Britain: *ednesda, &or eCample, is 2dinAs =or *odinAs< da, (i (o8ld be more apparent i& (e prono8ned it as itAs spelled, *ednAs !a? 8rsda is orAs da? %rida is te da o& %rea, )oddess o& lo'e$ e last da o& te (eek staed oman, te rest o& it beame /erman$ In all omane lan)8a)es, s8 as %ren, Spanis, and Italian, te onnetion is still more ob'io8s, bea8se te 4 deri'e &rom anient .atin, in (i te das o& te (eek (ere named =in order, be)innin) (it S8nda< a&ter te S8n, te oon, ars, er8r, >8piter, #en8s, and Sat8rn$ =e S8nAs da beame te .ordAs da$< e o8ld a'e named te das in order o& te bri)tness o& te orrespondin) astronomial bodiesGte S8n, te oon, #en8s, >8piter, ars, Sat8rn, er8r =and t8s S8nda, onda, %rida, 8rsda, 8esda, Sat8rda, *ednesda< Gb8t te did not$ I& te das o& te (eek in omane lan)8a)es ad been ordered b distane &rom te S8n, te seK8ene (o8ld be S8nda, *ednesda, %rida, onda, 8esda, 8rsda, Sat8rda$ No one kne( te order o& te planets, to8), bak (en (e (ere namin) planets, )ods, and das o& te (eek$ e orderin) o& te das o& te (eek seems arbitrar, alto8) peraps it does akno(led)e te prima o& te S8n$ is olletion o& se'en )ods, se'en das, and se'en (orlds te S8n, te oon, and te &i'e (anderin) planets entered te pereptions o& people e'er(ere$ e n8mber se'en be)an to aK8ire s8pernat8ral onnotations$ ere (ere se'en ea'ens, te transparent sperial sells, entered on te Eart, tat (ere ima)ined to make tese (orlds mo'e$ e o8termostGte se'ent ea'enGis (ere te &iCed stars (ere ima)ined to reside$ ere are Se'en !as o& +reation =i& (e inl8de /odAs da o& rest<, se'en ori&ies to te ead, se'en 'irt8es, se'en deadl sins, se'en e'il demons in S8merian mt$ se'en 'o(els in te /reek alpabet =ea a&&iliated (it a planetar )od<, Se'en /o'ernors o& !estin aordin) to te ermetists, Se'en /reat Books o& aniaeism, Se'en Saraments, Se'en Sa)es o& nient /reee, and se'en alemial bodies =)old, sil'er, iron, mer8r, lead, tin, and opperG)old still assoiated (it te S8n, sil'er (it te oon, iron (it ars, et$<$ e se'ent son o& a se'ent son is endo(ed (it s8pernat8ral po(ers$ Se'en is a l8k n8mber$ In te Ne( estamentAs Book o& e'elations, se'en seals on a sroll are opened, se'en tr8mpets are so8nded, se'en bo(ls are &illed$ St$ 8)8stine obs8rel ar)8ed &or te msti importane o& se'en on te )ro8nds tat tree is te &irst (ole n8mber tat is odd =(at abo8t oneD<, &o8r te &irst tat is e'en =(at abo8t t(oD<, and o& tese $ $ $ se'en is omposed$ nd so on$ E'en in o8r time tese assoiations lin)er$ e eCistene e'en o& te &o8r satellites o& >8piter tat /alileo diso'eredGardl planets G(as disbelie'ed on te )ro8nds tat it allen)ed te preedene o& te n8mber se'en$ s aeptane o& te +opernian sstem )re(, te Eart (as added to te list o& planets, and te S8n and oon (ere remo'ed$ 8s, tere seemed to be onl siC planets =er8r, #en8s, Eart, ars, >8piter, and Sat8rn<$ So learned aademi ar)8ments (ere in'ented so(in) ( tere
a to be siC$ %or eCample, siC is te &irst per&et n8mber, eK8al to te s8m o& its di'isors =1
65
" 3<$ T$E$!$ nd an(a, tere (ere onl siC das o& reation, not se'en$ eople &o8nd (as to aommodate &rom se'en planets to siC$ s tose adept at n8merolo)ial mstiism adH8sted to te +opernian sstem, tis sel&ind8l)ent mode o& tinkin) spilled o'er &rom planets to moons$ e Eart ad one moon? >8piter ad te &o8r /alilean moons$ at made &i'e$ +learl one (as missin)$ =!onAt &or)et: SiC is te &irst per&et n8mber$< *en 8)ens diso'ered itan in 1655, e and man oters on'ined temsel'es tat it (as te last: SiC planets, siC moons, and /odAs in is ea'en$ e istorian o& siene I$ Bernard +oen o& ar'ard ni'ersit as pointed o8t tat 8)ens at8all )a'e 8p searin) &or oter moons bea8se it (as apparent, &rom s8 ar)8ments, tat no more (ere to be &o8nd$ SiCteen ears later, ironiall (it 8)ens in attendane, /$ !$ +assim
1
o& te aris 2bser'ator diso'ered a se'ent moonGIapet8s, a
biarre (orld (it one emispere blak and te oter (ite, in an orbit eCterior to itanAs$ Sortl a&ter, +assim diso'ered ea, te neCt Sat8rnian moon interior to itan$ ere (as anoter opport8nit &or n8merolo), tis time arnessed to te pratial task o& &latterin) patrons$ +assim added 8p te n8mber o& planets =siC< and te n8mber o& satellites =ei)t< and )ot &o8rteen$ No( it so appened tat te man (o b8ilt +assimAs obser'ator &or im and paid is salar (as .o8is I# o& %rane, te S8n in)$ e astronomer promptl presented tese t(o ne( moons to is so'erei)n and prolaimed tat .o8isAs onK8ests reaed to te ends o& te Solar Sstem$ !isreetl, +assim ten baked o&& &rom lookin) &or more moons? +oen s8))ests e (as a&raid one more mi)t no( o&&end .o8isGa monar not to be tri&led (it, (o (o8ld sortl be tro(in) is s8bHets into d8n)eons &or te rime o& bein) rotestants$ (el'e ears later, to8), +assim ret8rned to te sear and &o8ndG do8btless (it a meas8re o& trepidationGanoter t(o moons$ =It is probabl a )ood tin) tat (e a'e not ontin8ed in tis 'ein? oter(ise %rane (o8ld a'e been b8rdened b se'entsome-odd Bo8rbon kin)s named .o8is$< In WHEN CLAIMS OF NEW WORLDS WERE MADE
te late ei)teent ent8r, te &ore o& s8
n8merolo)ial ar)8ments ad m8 dissipated$ Still, it (as (it a real sense o& s8rprise tat people eard in 17;1 abo8t a ne( planet, diso'ered tro8) te telesope$ Ne( moons (ere omparati'el 8nimpressi'e, espeiall a&ter te &irst siC or ei)t$ B8t tat tere (ere ne( plane" to be &o8nd and tat 8mans ad de'ised te means to do so (ere bot onsidered astonisin), and properl so$ I& tere is one pre'io8sl 8nkno(n planet, tere ma be man moreGin tis solar sstem and in oters$ *o an tell (at mi)t be &o8nd i& a m8ltit8de o& ne( (orlds are idin) in te darkD e diso'er (as made not e'en b a pro&essional astronomer b8t b *illiam ersel, a m8siian (ose relati'es ad ome to Britain (it te &amil o& anoter an)li&ied /erman, te rei)nin) monar and &8t8re oppressor o& te merian olonists, /eor)e III$ It beame erselAs (is to all te planet /eor)e =/eor)eAs Star, at8all<, a&ter is patron$ b8t, pro'identiall, te name didnAt stik$ =stronomers seem to a'e been 'er b8s b8tterin) 8p 1
&ter (om te E8ropean-merian mission to te Sat8rn sstem is named$
66
kin)s$< Instead, te planet tat ersel &o8nd is alled ran8s =an ineCa8stible so8re o& ilarit rene(ed in ea )eneration o& En)lis-speakin) nine-ear-olds<$ It is named a&ter te anient sk )od (o, aordin) to /reek mt, (as Sat8rnAs &ater and t8s te )rand&ater o& te 2lmpian )ods$ *e no lon)er onsider te S8n and oon to be planets, and i)norin) te omparati'el insi)ni&iant asteroids and omets, o8nt ran8s as te se'ent planet in order &rom te S8n =er8r, #en8s, Eart, ars, >8piter, Sat8rn, ran8s, Nept8ne, l8to<$ It is te &irst planet 8nkno(n to te anients$ e &o8r o8ter, >o'ian, planets t8rn o8t to be 'er di&&erent &rom te &o8r inner, terrestrial, planets$ l8to is a separate ase$ s te ears passed and te K8alit o& astronomial instr8ments 8npro'ed, (e be)an to learn more abo8t distant ran8s$ *at re&lets te dim s8nli)t bak to 8s is no solid s8r&ae, b8t atmospere and lo8ds H8st as &or itan, #en8s, >8piter Sat8rn, and Nept8ne$ e air on ran8s is made o& dro)en and eli8m, te t(o simplest )ases$ etane and oter droarbons are also present$ >8st belo( te lo8ds 'isible to Eartbo8nd obser'ers is a massi'e atmospere (it enormo8s K8antities o& ammonia, dro)en s8l&ide, and, espeiall, (ater$ t dept on >8piter and Sat8rn, te press8res are so )reat tat atoms s(eat eletrons, and te air beomes a metal$ at does not seem to appen on less massi'e ran8s, bea8se te press8res at dept are less$ Still deeper, diso'ered onl b its s8btle t8)s on ran8sA moons, (oll inaessible to 'ie(, 8nder te r8sin) (ei)t o& te o'erlin) atmospere, is a rok s8r&ae$ bi) Eartlike planet is idin) do(n tere, s(ated in an immense blanket o& air$ e EartAs s8r&ae temperat8re is d8e to te s8nli)t it interepts$ 8rn o&& te S8n and te planet soon illsGnot to tri&lin) ntarti old, not H8st so old tat te oeans &reee, b8t to a old so intense tat te 'er air preipitates o8t, &ormin) a ten-meter-tik laer o& oC)en and nitro)en sno(s o'erin) te (ole planet$ e little bit o& ener) tat trikles 8p &rom te EartAs ot interior (o8ld be ins8&&iient to melt tese sno(s$ %or >8piter, Sat8rn, and Nept8ne itAs di&&erent$ ereAs abo8t as m8 eat po8rin) o8t &rom teir interiors as te aK8ire &rom te (armt o& te distant S8n$ 8rn o&& te S8n, and te (o8ld be onl a little a&&eted$ B8t ran8s is anoter stor$ ran8s is an anomal amon) te >o'ian planets$ ran8s is like te Eart: ereAs 'er little intrinsi eat po8rin) o8t$ *e a'e no )ood 8nderstandin) o& ( tis so8ld be, ( ran8sG(i in man respets is so similar to Nept8neGso8ld lak a potent so8re o& internal eat$ %or tis reason, amon) oters, (e annot sa (e 8nderstand (at is )oin) on in te deep interiors o& tese mi)t (orlds$ ran8s is lin) on its side as it )oes aro8nd te S8n$ In te 1990s$ te so8t pole is eated b te S8n, and it is tis pole tat Eartbo8nd obser'ers at te end o& te t(entiet ent8r see (en te look at ran8s$ It takes ran8s ;4 Eart ears to make one ir8it o& te S8n$ So in te "030s, te nort pole (ill be s8n(ard =and Eart(ard<$ In te "070s te so8t pole (ill be pointin) to te S8n one a)ain$ In bet(een, Eartbo8nd astronomers (ill be lookin) mainl at eK8atorial latit8des$ ll te oter planets spin m8 more 8pri)t in teir orbits$ No one is s8re o& te reason &or ran8sA anomalo8s spin? te most promisin) s8))estion is tat sometime in its earl istor, billions o& ears a)o, it (as str8k b a ro)8e planet, abo8t te sie o& te Eart, in a 67
i)l eentri orbit$ S8 a ollision, i& it e'er appened, m8st a'e (orked m8 t8m8lt in te ran8s sstem? &or all (e kno(, tere ma be oter 'esti)es o& anient a'o still le&t &or 8s to &ind$ B8t ran8sA remoteness tends to )8ard its msteries$ In 1977 a team o& sientists led b >ames Elliot, ten o& +ornell ni'ersit, aidentall diso'ered tat, like Sat8rn, ran8s as rin)s$ e sientists (ere &lin) o'er te Indian 2ean in a speial NS airplaneGte 8iper irborne 2bser'atorGto (itness te passa)e o& ran8s in &ront o& a star$ =S8 passa)es, or o8ltations as teAre alled, appen &rom time to time, preisel bea8se ran8s slo(l mo'es (it respet to te distant stars$< e obser'ers (ere s8rprised to &ind tat te star (inked on and o&& se'eral times H8st be&ore it passed beind ran8s and its atmospere, ten se'eral times more H8st a&ter it emer)ed$ Sine te patterns o& (inkin) on and o&& (ere te same be&ore and a&ter o8ltation, tis &indin) =and m8 s8bseK8ent (ork< as led to te diso'er o& nine 'er tin, 'er dark ir8mplanetar rin)s, )i'in) ran8s te appearane o& a b8llAs-ee in te sk$ S8rro8ndin) te rin)s, Eartbo8nd obser'ers 8nderstood (ere te onentri orbits o& te &i'e moons ten kno(n: iranda, riel, mbriel, itania, and 2beron$ eAre named a&ter araters in SakespeareAs Miummer ig" .ream and /e /empe" and in leCander opeAs /e ape o "e &o7k3 /
te ran8s sstemGte planet, its rin)s, and its
moonsGbe)an on >an8ar "4, 19;6 $ 2n tat da, a&t er a Ho8rne o& ;M ears, te Vo$ager 2 spaera&t sailed 'er near to iranda, and it te b8llAs-ee in te sk$ ran8sA )ra'it ten &l8n) it on to Nept8ne$ e spaera&t ret8rned 4,300 lose-8p pit8res o& te ran8s sstem and a (ealt o& oter data$ ran8s (as &o8nd to be s8rro8nded b an intense radiation belt, eletrons and protons trapped b te planetAs ma)neti &ield$ Vo$ager &le( tro8) tis radiation belt, meas8rin) te ma)neti &ield and te trapped ar)ed partiles as it (ent$ It also detetedGin an)in) timbres, armonies, and n8ane, b8t mainl in or"iimoGa aopon o& radio (a'es )enerated b te speedin), trapped partiles$ Sometin) similar (as diso'ered on >8piter and Sat8rn and (o8ld be later &o8nd at Nept8neGb8t al(as (it a teme and o8nterpoint arateristi o& ea (orld$
1
e so named it bea8se o& te (ords spoken b iranda, te eroine o& /e empest: 2 bra'e ne( (orld, at as s8 people inAt$ =o *i rospero replies, Ais ne( to tee$ >8st so$ .ike all te oter (orlds in te Solar Sstem, iranda is abo8t 4$5 billion ears old$<
6;
2n Eart te ma)neti and )eo)rapial poles are K8ite lose to)eter$ 2n ran8s te ma)neti aCis and te aCis o& rotation are tilted a(a &rom ea oter b some 60 de)rees$ No one et 8nderstands (: Some a'e s8))ested tat (e are atin) ran8s in a re'ersal o& its nort and so8t ma)neti poles, as periodiall appens on Eart$ 2ters propose tat tis too is te onseK8ene o& tat mi)t, anient ollision tat knoked te planet o'er$ B8t (e do not kno($ ran8s is emittin) m8 more 8ltra'iolet li)t tan itAs reei'in) &rom te S8n, probabl )enerated b ar)ed partiles leakin) o8t o& te ma)netospere and strikin) its 8pper atmospere$ %rom a 'anta)e point in te ran8s sstem, te spaera&t eCamined a bri)t star (inkin) on and o&& as te rin)s o& ran8s passed b$ Ne( &aint d8st bands (ere &o8nd$ %rom te perspeti'e o& Eart, te spaera&t passed beind ran8s? so te radio si)nals it (as transmittin) bak ome passed tan)entiall tro8) te ranian atmospere, probin) itGto belo( its metane lo8ds$ 'ast and deep oean, peraps ;,000 kilometers tik, o& s8pereated liK8id (ater &loatin) in te air is in&erred b some$ mon) te prinipal )lories o& te ran8s eno8nter (ere te pit8res$ *it Vo$agerAs t(o tele'ision ameras, (e diso'ered ten ne( moons, determined te len)t o& te da in te lo8ds o& ran8s =abo8t 17 o8rs<, and st8died abo8t a doen rin)s$ e most speta8lar pit8res (ere tose ret8rned &rom te &i'e lar)er, pre'io8sl kno(n moons o& ran8s, espeiall te smallest o& tem, 8iperAs iranda$ Its s8r&ae is a t8m8lt o& &a8lt 'alles, parallel rid)es, seer li&&s, lo( mo8ntains, impat raters, and &roen &loods o& one-molten s8r&ae material$ is t8rmoiled landsape is 8neCpeted &or a small, old, i (orld so distant &rom te S8n$ eraps te s8r&ae (as melted and re(orked in some lon)-)one epo (en a )ra'itational resonane bet(een ran8s, iranda, and riel p8mped ener) &rom te nearb planet into irandaAs interior$ 2r peraps (e are seein) te res8lts o& te primordial ollision tat is to8)t to a'e knoked ran8s o'er$ 2r, H8st onei'abl, mabe iranda (as one 8tterl destroed, dismembered, blasted into smitereens b a (ild areenin) (orld, (it man ollision &ra)ments still le&t in irandaAs orbit$ e sards and remnants, slo(l ollidin), )ra'itationall attratin) one anoter, ma a'e re-a))re)ated into H8st s8 a H8mbled, pat, 8n&inised (orld as iranda is toda$ %or me, tereAs sometin) eerie abo8t te pit8res o& d8sk iranda, bea8se I an remember so (ell (en it V'as onl a &aint point o& li)t almost lost in te )lare o& ran8s, diso'ered tro8) )reat di&&i8lt b dint o& te astronomerAs skills and patiene$ In onl al& a li&etime it as )one &rom an 8ndiso'ered (orld to a destination (ose anient and idiosnrati serets a'e been at least partiall re'ealed$
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SI E %2NIES 2% E S2. SSE $ $ $ b te sore 2& ritonAs .ake $ $$ I (ill lear m breast o& serets$ —EII!ES, I2N =+$ 413 B$+$<
Nept8ne (as te &inal port o& all in Vo$ager 2As )rand to8r o& te Solar Sstem$ s8all, it is to8)t o& as te pen8ltimate planet, (it l8to te o8termost$ B8t bea8se o& l8toAs stretedo8t, elliptial orbit, Nept8ne as latel been te o8termost planet, and (ill remain so 8ntil 1999$ pial temperat8res in its 8pper lo8ds are abo8t -"40U+, bea8se it is so &ar &rom te (armin) ras o& te S8n$ It (o8ld be older still eCept &or te eat (ellin) 8p &rom its interior$ Nept8ne )lides alon) te em o& interstellar ni)t$ It is so &ar a(a tat, in its sk, te S8n appears as little more tan an eCtremel bri)t star$ o( &arD So &ar a(a tat it as et to omplete a sin)le trip aro8nd te S8n, a Nept8nian ear, sine its diso'er in 1;46$ 1 ItAs so &ar a(a tat it annot be seen (it te naked ee$ ItAs so &ar a(a tat it takes li)tG&aster tan (i notin) an )oGmore tan &i'e o8rs to )et &rom Nept8ne to Eart$
1
It takes so lon) to ir8it te S8n bea8se its orbit is so 'ast, "3 billion miles aro8nd, and bea8se te &ore o& te S8nAs )ra'itG (i keeps it &rom &lin) o8t into interstellar spaeGis at tat distant omparati'el &eeble, less tan a to8sandt (at it is in te EartAs 'iinit$
71
*en Vo$ager 2 raed tro8) te Nept8ne sstem in 19;9, its ameras, spetrometers, partile and &ield detetors, and oter instr8ments (ere &e'erisl eCaminin) te planet, its moons, and its rin)s$ e planet itsel&, like its o8sins >8piter, Sat8rn, and ran8s, is a )iant$ E'er planet is an Eartlike (orld at eartGb8t te &o8r )as )iants (ear elaborate, 8mbersome dis)8ises$ >8piter and Sat8rn are )reat )as (orlds (it relati'el small rok and i ores$ B8t ran8s and Nept8ne are &8ndamentall rok and ie (orlds s(addled in dense atmosperes tat ide tem &rom 'ie($ Nept8ne is &o8r times bi))er tan te Eart$ *en (e look do(n on its ool, a8stere bl8eness, a)ain (e are seein) onl atmospere and lo8dsGno solid s8r&ae$ )ain, te atmospere is made mainl o& dro)en and eli8m, (it a little metane and traes o& oter droarbons$ ere ma also be some nitro)en$ e bri)t lo8ds, (i seem to be metane rstals, &loat abo'e tik, deeper lo8ds o& 8nkno(n omposition$ %rom te motion o& te lo8ds (e diso'ered &iere (inds, approain) te loal speed o& so8nd$ /reat !ark Spot (as &o8nd, 8rio8sl at almost te same latit8de as te /reat ed Spot on >8piter$ e a8re olor seems appropriate &or a planet named a&ter te )od o& te sea$ S8rro8ndin) tis diml lit, ill, storm, remote (orld isGere alsoGa sstem o& rin)s, ea omposed o& inn8merable orbitin) obHet s ran)in) in sie &rom te &ine partiles in i)arette smoke to small tr8ks$ .ike te rin)s o& te oter >o'ian planets, tose o& Nept8ne seem to be e'anesentGit is al8lated tat )ra'it and solar radiation (ill disr8pt tem in m8 less tan te a)e o& te Solar Sstem$ I& te are destroed K8ikl, (e m8st see tem onl bea8se te (ere made reentl$ B8t o( an rin)s be madeD e bi))est moon in te Nept8ne sstem is alled riton$ 1 Nearl siC o& o8r das are reK8ired &or it to orbit Nept8ne, (iGalone amon) bi) moons in te Solar SstemGit does in te opposite diretion to (i its planet spins =lok(ise i& (e sa Nept8ne rotates o8nterlok(ise<$ riton as a nitro)en-ri atmospere, some(at similar to itanAs? b8t, bea8se te air and ae are m8 tinner, (e an see its s8r&ae$ e landsapes are 'aried and splendid$ is is a (orld o& iesGnitro)en ie, metane ie, probabl 8nderlain b more &amiliar (ater ie and rok$ ere are impat basins, (i seem to a'e been &looded (it liK8id be&ore re&reein) =so tere one (ere lakes on riton
obert /oddard, te in'entor o& te modern liK8id-&8eled roket, en'isioned a time (en eCpeditions to te stars (o8ld be
o8t&itted on and la8ned &rom riton$ is (as in a 19"7 a&terto8)t to a 191; and(ritten man8sript alled e .ast i)ration$ +onsidered m8 too darin) &or p8bliation, it (as deposited in a &riendAs sa&e$ e o'er pa)e bears a (arnin): eQseR notes so8ld be read toro8)l onlb an optimist$
7"
rotationG8nlike te sit8ation (it te Eart and its moon, and (it most o& te lar)e moons in te Solar Sstem$ I& riton ad &ormed o8t o& te same spinnin) disk tat made Nept8ne, it o8)t to be )oin) aro8nd Nept8ne in te same diretion tat Nept8ne rotates$ So riton (as not made &rom te ori)inal loal neb8la aro8nd Nept8ne, b8t arose some(ere elseGperaps &ar beond l8toGand (as b ane )ra'itationall apt8red (en it passed too lose to Nept8ne$ is e'ent so8ld a'e raised enormo8s solid-bod tides in riton, meltin) te s8r&ae and s(eepin) a(a all te past topo)rap$ In some plaes te s8r&ae is as bri)t and (ite as &resl &allen ntarti sno(s =and ma o&&er a skiin) eCperiene 8nri'aled in all te Solar Sstem<$ Else(ere tereAs a tint, ran)in) &rom pink to bro(n$ 2ne possible eCplanation: %resl &allen sno(s o& nitro)en, metane, and oter droarbons are irradiated b solar 8ltra'iolet li)t and b eletrons trapped in te ma)neti &ield o& Nept8ne, tro8) (i riton plo(s$ *e kno( tat s8 irradiation (ill on'ert te sno(s =like te orrespondin) )ases< to ompleC, dark, reddis or)ani sediments, ie tolinsGnotin) ali'e, b8t ere too omposed o& some o& te mole8les impliated in te ori)in o& li&e on Eart &o8r billion ears a)o$ In loal (inter, laers o& ie and sno( b8ild 8p on te s8r&ae$ =28r (inters, meri&8ll, are onl 4 perent as lon)$< ro8) te sprin), te are slo(l trans&ormed, more and more reddis or)ani mole8les a8m8latin)$ B s8mmertime, te ie and sno( a'e e'aporated? te )ases so released mi)rate al&(a aross te planet to te (inter emispere and tere o'er te s8r&ae (it ie and sno( a)ain$ B8t te reddis or)ani mole8les do not 'aporie and are not transportedGa la) deposit, te are neCt (inter o'ered o'er b ne( sno(s, (i are in t8rn irradiated, and b te &ollo(in) s8mmer te a8m8lation is tiker$ s time )oes on, s8bstantial amo8nts o& or)ani matter are b8ilt 8p on te s8r&ae o& riton, (i ma ao8nt &or its deliate olor markin)s$ e streaks be)in in small, dark so8re re)ions, peraps (en te (armt o& sprin) and s8mmer eats s8bs8r&ae 'olatile sno(s$ s te 'aporie, )as omes )8sin) o8t as in a )eser, blo(in) o&& less-'olatile s8r&ae sno(s and dark or)anis$ re'ailin) lo(-speed (inds arr a(a te dark or)anis, (i slo(l sediment o8t o& te tin air, are deposited on te )ro8nd, and )enerate te appearane o& te streaks$ is, at least, is one reonstr8tion o& reent ritonian istor$ riton ma a'e lar)e, seasonal polar aps o& smoot nitro)en ie 8nderlin) laers o& dark or)ani materials$ Nitro)en sno(s seem reentl to a'e &allen at te eK8ator$ Sno(&alls, )esers, (indblo(n or)ani d8st, and i)-altit8de aes (ere entirel 8neCpeted on a (orld (it so tin an atmospere$ * is te air so tinD Bea8se riton is so &ar &rom te S8n$ *ere o8 someo( to pik tis (orld 8p and mo'e it into orbit aro8nd Sat8rn, te nitro)en and metane ies (o8ld K8ikl e'aporate, a m8 denser atmospere o& )aseo8s nitro)en and metane (o8ld &orm, and radiation (o8ld )enerate an opaK8e tolin ae$ It (o8ld beome a (orld 'er like itan$ +on'ersel, i& o8 mo'ed itan into orbit abo8t Nept8ne, almost all its atmospere (o8ld &reee o8t as sno(s and ies, te tolin (o8ld &all o8t and not be replaed, te air (o8ld lear, and te s8r&ae (o8ld beome 'isible in ordinar li)t$ It (o8ld beome a (orld 'er like riton$ 73
ese t(o (orlds are not idential$ e interior o& itan seems to ontain m8 more ie tan tat o& riton, and m8 less rok$ itanAs diameter is almost t(ie tat o& riton$ Still, i& plaed at te same distane &rom te S8n te (o8ld look like sisters$ lan Stern o& te So8t(est esear Instit8te s8))ests tat te are t(o members o& a 'ast olletion o& small (orlds ri in nitro)en and metane tat &ormed in te earl Solar Sstem$ l8to, et to be 'isited b a spaera&t, appears to be anoter member o& tis )ro8p$ an more ma a(ait diso'er beond l8to$ e tin atmosperes and i s8r&aes o& all tese (orlds are bein) irradiatedGb osmi ras, i& notin) else and nitro)enGri or)ani ompo8nds are bein) &ormed$ It looks as i& te st8&& o& li&e is sittin) not H8st on itan, b8t tro8)o8t te old, diml lit o8ter reaes o& o8r planetar sstem$ noter lass o& small obHets as reentl been diso'ered, (ose orbits take temGat least part o& te timeGbeond Nept8ne and l8to$ Sometimes alled minor planets or asteroids, te are more likel to be inati'e omets =(it no tails, o& o8rse? so &ar &rom te S8n, teir ies annot readil 'aporie<$ B8t te are m8 bi))er tan te r8n-o&-te-mill omets (e kno($ e ma be te 'an)8ard o& a 'ast arra o& small (orlds tat eCtends &rom te orbit o& l8to al&(a to te nearest star$ e innermost pro'ine o& te 2ort +omet +lo8d, o& (i tese ne( obHets ma be members, is alled te 8iper Belt, a&ter m mentor /erard 8iper, (o &irst s8))ested tat it so8ld eCist$ Sort-period ometsGlike alleAsGarise in te 8iper Belt, respond to )ra'itational t8)s, s(eep into te inner part o& te Solar Sstem, )ro( teir tails, and )rae o8r skies$ Bak in te late nineteent ent8r, tese b8ildin) bloks o& (orldsGten mere poteses G(ere alled planetesimals$ e &la'or o& te (ord is, I s8ppose, sometin) like tat o& in&initesimals: o8 need an in&inite n8mber o& tem to make antin)$ ItAs not K8ite "a" eCtreme (it planetesimals, alto8) a 'er lar)e n8mber o& tem (o8ld be reK8ired to make a planet$ %or eCample, trillions o& bodies ea a kilometer in sie (o8ld be needed to oalese to make a planet (it te mass o& te Eart$ 2ne tere (ere m8 lar)er n8mbers o& (orldlets in te planetar part o& te Solar Sstem$ ost o& tem are no( )oneGeHeted into interstellar spae, &allen into te S8n, or sari&ied in te )reat enterprise o& b8ildin) moons and planets$ B8t o8t beond Nept8ne and l8to te disards, te le&to'ers tat (ere ne'er a))re)ated into (orlds, ma be (aitin)Ga &e( lar)is ones in te 100-kilometer ran)e, and st8pe&in) n8mbers o& kilometer-sied and smaller bodies pepperin) te o8ter Solar Sstem all te (a o8t to te 2ort +lo8d$ In tis sense tere are planets beond Nept8ne and l8toGb8t te are not nearl as bi) as te >o'ian planets, or e'en l8to$ .ar)er (orlds ma, &or all (e kno(, also be idin) in te dark beond l8to, (orlds tat an properl be alled planets$ e &arter a(a te are, te less likel it is tat (e (o8ld a'e deteted tem$ e annot lie H8st beond Nept8ne, to8)? teir )ra'itational t8)s (o8ld a'e pereptibl altered te orbits o& Nept8ne and l8to, and te
Pioneer 10 and 11 and Vo$ager 1 and " spaera&t$ e ne(l diso'ered ometar bodies =(it names like 199"TB and 1993%*< are not planets in tis sense$ I& o8r detetion tresold as H8st enompassed tem, man more o& tem probabl remain to be diso'ered in te o8ter Solar SstemGso &ar a(a tat teAre ard to see 74
&rom Eart, so distant tat itAs a lon) Ho8rne to )et to tem$ B8t small, K8ik sips to l8to and beond are (itin o8r abilit$ It (o8ld make )ood sense to dispat one b l8to and its moon +aron, and ten, i& (e an, to make a lose pass b one o& te deniens o& te 8iper +omet Belt$ e rok Eartlike ores o& ran8s and Nept8ne seem to a'e areted &irst, and ten )ra'itationall attrated massi'e amo8nts o& dro)en and eli8m )as &rom te anient neb8la o8t o& (i te planets &ormed$ 2ri)inall, te li'ed in a ailstorm$ eir )ra'ities (ere H8st s8&&iient to eHet i (orldlets, (en te ame too lose, &ar o8t beond te realm o& te planets, to pop8late te 2ort +omet +lo8d$ >8piter and Sat8rn beame )as )iants b te same proess$ B8t teir )ra'ities (ere too stron) to pop8late te 2ort +lo8d: Ie (orlds tat ame lose to tem (ere )ra'itationall pited o8t o& te Solar Sstem entirelGdestined to (ander &ore'er in te )reat dark bet(een te stars$ So te lo'el omets tat on oasion ro8se 8s 8mans to (onder and to a(e, tat rater te s8r&aes o& inner planets and o8ter moons, and tat no( and ten endan)er li&e on Eart (o8ld be 8nkno(n and 8ntreatenin) ad ran8s and Nept8ne not )ro(n to be )iant (orlds &o8r and a al& billion ears a)o$
THIS IS THE PLACE
&or a brie& interl8de on planets &ar beond Nept8ne and l8to, planets o&
oter stars$ an nearb stars are s8rro8nded b tin disks o& orbitin) )as and d8st, o&ten eCtendin) to 8ndreds o& astronomial 8nits =< &rom te loal star =te o8termost planets, Nept8ne and l8to, are abo8t 40 &rom o8r S8n<$ o8n)er S8n-like stars are m8 more likel to a'e disks tan older ones$ In some ases, tereAs a ole in te enter o& te disk as in a pono)rap reord$ e ole eCtends o8t &rom te star to peraps 30 or 40 $ is is tr8e, &or eCample, &or te disks s8rro8ndin) te stars #e)a and Epsilon Eridam$ e ole in te disk s8rro8ndin) Beta itoris eCtends to onl 15 &rom te star$ ere is a real possibilit tat tese inner, d8st-&ree ones a'e been leaned 8p b planets tat reentl &ormed tere$ Indeed, tis s(eepin)-o8t proess is predited &or te earl istor o& o8r planetar sstem$ s obser'ations impro'e, peraps (e (ill see telltale details in te on&i)8ration o& d8st and d8st-&ree ones tat (ill indiate te presene o& planets too small and dark to be seen diretl$ Spetrosopi data s8))est tat tese disks are 8rnin) and tat matter is &allin) in on te entral starsGperaps &rom omets &ormed in te disk, de&leted b te 8nseen planets, and e'aporatin) as te approa too lose to te loal s8n$ Bea8se planets are small and sine b re&leted li)t, te tend to be (ased o8t in te )lare o& te loal s8n$ Ne'erteless, man e&&orts are no( 8nder (a to &ind &8ll &ormed planets aro8nd nearb starsGb detetin) a &aint brie& dimmin) o& starli)t as a dark planet interposes itsel& bet(een te star and te obser'er on Eart? or b sensin) a &aint (obble in te motion o& te star as itAs t8))ed &irst one (a and ten anoter b an oter(ise in'isible orbitin) ompanion$ Spaeborne teniK8es (ill be m8 more sensiti'e$ >o'ian planet )oin) aro8nd a nearb star is abo8t a billion times &ainter tan its s8n? ne'erteless, a ne( )eneration o& )ro8nd75
based telesopes tat an ompensate &or te t(inklin) in te EartAs atmospere ma soon be able to detet s8 planets in onl a &e( o8rsA obser'in) time$ terrestrial planet o& a nei)borin) star is a 8ndred times &ainter still? b8t it no( seems tat omparati'el ineCpensi'e spaera&t, abo'e te EartAs atmospere, mi)t be able to detet oter Earts$ None o& tese seares as s8eeded et, b8t (e are learl on te 'er)e o& bein) able to detet at least >8piter-sied planets aro8nd te nearest starsGi& tere are an to be &o8nd$ most important and serendipito8s reent diso'er is o& a bona &ide planetar sstem aro8nd an 8nlikel star, some 1,300 li)t-ears a(a, &o8nd b a most 8neCpeted teniK8e: e p8lsar desi)nated B1"571" is a rapidl rotatin) ne8tron star, an 8nbelie'abl dense s8n, te remnant o& a massi'e star tat s8&&ered a s8perno'a eCplosion$ It spins, at a rate meas8red to impressi'e preision, one e'er 0$006"1;53193;;1;7 seonds$ is p8lsar is p8sin) 10,000 rpm$ +ar)ed partiles trapped in its intense ma)neti &ield )enerate radio (a'es tat are ast aross te Eart, abo8t 160 &likers a seond$ Small b8t disernible an)es in te &las rate (ere tentati'el interpreted b leCander *olsan, no( at ennsl'ania State ni'ersit, in 1991G as a tin re&leC motion o& te p8lsar in response to te presene o& planets$ In 1994 te predited m8t8al )ra'itational interations o& tese planets (ere on&irmed b *olsan &rom a st8d o& timin) resid8als at te miroseond le'el o'er te inter'enin) ears$ e e'idene tat tese are tr8l ne( planets and not starK8akes on te ne8tr on star s8r&ae =or sometin)< is no( o'er(elmin)Gor, as *olsan p8t it, irre&8table? a ne( solar sstem is 8nambi)8o8sl identi&ied$ nlike all te oter teniK8es, te p8lsar timin) metod makes lose-in terrestrial planets omparati'el eas and more distant >o'ian planets omparati'el di&&i8lt to detet$ lanet +, some "$; times more massi'e tan te Eart, orbits te p8lsar e'er 9; das at a distane o& 0$47 astronomial 8nits 1 =
e Eart, b de&inition, is 1 &rom its star, te S8n$
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sstem eCist$< 2& o8rse, (e donAt e'en kno( tat s8 (orlds (o8ld retain teir atmosperes? peraps an atmosperes (ere stripped a(a in te s8perno'a eCplosion, i& te date bak tat &ar$ B8t (e do seem to be detetin) a reo)niable planetar sstem$ an more are likel to beome kno(n in omin) deades, aro8nd ordinar S8n-like stars as (ell as (ite d(ar&s, p8lsars, and oter end states o& stellar e'ol8tion$ E'ent8all, (e (ill a'e a list o& planetar sstemsGea peraps (it terrestrials and >o'ians and mabe ne( lasses o& planets$ *e (ill eCamine tese (orlds, spetrosopiall and in oter (as$ *e (ill be searin) &or ne( Earts and oter li&e$
te o8ter Solar Sstem did Vo$ager &ind si)ns o& li&e, m8 less intelli)ene$ ere (as or)ani atter )aloreGte st8&& o& li&e, te premonitions o& li&e, peraps b8t as &ar as (e o8ld see, no li&e$ ere (as no oC)en in teir atmosperes, and no )ases pro&o8ndl o8t o& emial eK8ilibri8m, as metane is in te EartAs oC)en$ an o& te (orlds (ere painted (it s8btle olors, b8t none (it s8 distinti'e, sarp absorption &eat8res as loropll pro'ides o'er m8 o& te EartAs s8r&ae$ 2n 'er &e( (orlds (as Vo$ager able to resol'e details as small as a kilometer aross$ B tis standard, it (o8ld not a'e deteted e'en o8r o(n tenial i'iliation ad it been transplanted to te o8ter Solar Sstem$ B8t &or (at itAs (ort, (e &o8nd no re)8lar patternin), no )eometriation, no passion &or small irles, trian)les, sK8ares, or retan)les$ ere (ere no onstellations o& stead points o& li)t on te ni)t emisperes$ ere (ere no si)ns o& a tenial i'iliation re(orkin) te s8r&ae o& an o& tese (orlds$ e >o'ian planets are proli&i broadasters o& radio (a'esG)enerated in part b te ab8ndant trapped and beamed ar)ed partiles in teir ma)neti &ields, in part b li)tnin), and in part b teir ot interiors$ B8t none o& tis emission as te arater o& intelli)ent li&eGor so it seems to te eCperts in te &ield$ 2& o8rse o8r tinkin) ma be too narro($ *e ma be missin) sometin)$ %or eCample, tere is a little arbon dioCide in te atmospere o& itan, (i p8ts its nitro)enmetane atmospere o8t o& emial eK8ilibri8m$ I tink te +2 " is pro'ided b te stead pitter-patter o& omets &allin) into itanAs atmospereGb8t mabe not$ abe tereAs sometin) on te s8r&ae 8nao8ntabl )eneratin) +2 " in te &ae o& all tat metane$ e s8r&aes o& iranda and riton are 8nlike antin) else (e kno($ ere are 'ast ON NONE OF THE WORLDSIn
e'ron-saped land&orms and rissrossin) strai)t lines tat e'en sober planetar )eolo)ists one misie'o8sl desribed as i)(as$ *e tink (e =barel< 8nderstand tese land&orms in terms o& &a8lts and ollisions, b8t o& o8rse (e mi)t be (ron)$ e s8r&ae stains o& or)ani matterGsometimes, as on riton, deliatel 8edGare attrib8ted to ar)ed partiles prod8in) emial reation s in simple droarbon ies, )eneratin) more ompleC or)ani materials, and all tis a'in) notin) to do (it te intermediation o& li&e$ B8t o& o8rse (e mi)t be (ron)$ e ompleC pattern o& radio stati, b8rsts, and (istles tat (e reei'e &rom all &o8r >o'ian planets seems, in a )eneral (a, eCpliable b plasma psis and termal emission$ =8 o& te detail is not et (ell 8nderstood$< B8t o& o8rse (e mi)t be (ron)$
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*e a'e &o8nd notin) on doens o& (orlds so lear and strikin) as te si)ns o& li&e &o8nd b te %alileo spaera&t in its passa)es b te Eart$ .i&e is a potesis o& last resort$ o8 in'oke it onl (en tereAs no oter (a to eCplain (at o8 see$ I& I ad to H8d)e, I (o8ld sa tat tereAs no li&e on an o& te (orlds (eA'e st8died, eCept o& o8rse o8r o(n$ B8t I mi)t be (ron), and, ri)t or (ron), m H8d)ment is neessaril on&ined to tis Solar Sstem$ eraps on some ne( mission (eAll &ind sometin) di&&erent, sometin) strikin), sometin) (oll ineCpliable (it te ordinar tools o& planetar sieneGand trem8lo8sl, a8tio8sl, (e (ill in to(ard a biolo)ial eCplanation$ o(e'er, &or no( notin) reK8ires tat (e )o do(n s8 a pat$ So &ar, te onl li&e in te Solar Sstem is tat (i omes &rom Eart$ In te ran8s and Nept8ne sstems, te onl si)n o& li&e as been Vo$ager itsel&$ s (e identi& te planets o& oter stars, as (e &ind oter (orlds o& ro8)l te sie and mass o& te Eart, (e (ill sr8tinie tem &or li&e$ dense oC)en atmospere ma be detetable e'en on a (orld (eA'e ne'er ima)ed$ s &or te Eart, tat ma b itsel& be a si)n o& li&e$ n oC)en atmospere (it appreiable K8antities o& metane (o8ld almost ertainl be a si)n o& li&e, as (o8ld mod8lated radio emission$ Someda, &rom obser'ations o& o8r planetar sstem or anoter, te ne(s o& li&e else(ere ma be anno8ned o'er te mornin) o&&ee$ THE VOYAGERSPACECRAFTare
bo8nd &or te stars$ e are on esape traHetories &rom te Solar
Sstem, barrelin) alon) at almost a million miles a da$ e )ra'itational &ields o& >8piter, Sat8rn, ran8s, and Nept8ne a'e &l8n) tem at s8 i) speeds tat te a'e broken te bonds tat one tied tem to te S8n$ a'e te le&t te Solar Sstem etD e ans(er depends 'er m8 on o( o8 de&ine te bo8ndar o& te S8nAs realm$ I& itAs te orbit o& te o8termost )ood-sied planet, ten te Vo$ager spaera&t are alread lon) )one? tere are probabl no 8ndiso'ered Nept8nes$ I& o8 mean te o8termost planet, it ma be tat tere are oterGperaps riton-likeGplanets &ar beond Nept8ne and l8to? i& so, Vo$ager 1 and Vo$ager 2 are still (itin te Solar Sstem$ I& o8 de&ine te o8ter limits o& te Solar Sstem as te eliopa8seG(ere te interplanetar partiles and ma)neti &ields are replaed b teir interstellar o8nterpartsGten neiter Vo$ager as et le&t te Solar Sstem, alto8) te ma do so in te neCt &e( deades$ 1 B8t i& o8r de&inition o& te ed)e o& te Solar Sstem is te distane at (i o8r star an no lon)er old (orlds in orbit abo8t it, ten te Vo$agers (ill not lea'e te Solar Sstem &or 8ndreds o& ent8ries$ *eakl )rasped b te S8nAs )ra'it, in e'er diretion in te sk, is tat immense orde o& a trillion omets or more, te port +lo8d$ e t(o spaera&t (ill &inis teir passa)e tro8)
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adio si)nals tat bot Vo$agers deteted in 199" are to8)t to arise &rom te ollision o& po(er&8l )8sts o& solar (ind (it te tin )as tat lies bet(een te stars$ %rom te immense $po(er o& te si)nal =o'er 10 trillion (atts<, te distane to te eliopa8se an be estimated: abo8t 100 times te EartAs distane &rom te S8n$ t te speed itAs lea'in) te Solar Sstem, Vo$ager 1 mi)t piere te eliopa8se and enter interstellar spae aro8nd te ear "010$ I& its radioati'e po(er so8re is still (orkin), ne(s o& te rossin) (ill be radioed bak to te sta-at-omes on Eart$ e ener) released b te ollision o& tis sok (a'e (it te eliopa8se makes it te most po(er&8l so8re o& radio emission in te Solar Sstem$ It makes o8 (onder (eter e'en stron)er soks in oter planetar sstems mi)t e detetable b o8r radio telesope$
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te 2ort lo8d in anoter "0,000 ears or so$ en, at last, ompletin) teir lon) )ood-be to te Solar Sstem, broken &ree o& te )ra'itational sakles tat one bo8nd tem to te S8n, te
Vo$agers (ill make &or te open sea o& interstellar spae$ onl ten (ill ase (o o& teir mission be)in$ eir radio transmitters lon) dead, te spaera&t (ill (ander &or a)es in te alm, old interstellar blaknessG(ere tere is almost notin) to erode tem$ 2ne o8t o& te Solar Sstem, te (ill remain intat &or a billion ears or more, as te ir8mna'i)ate te enter o& te ilk *a )alaC$ *e do not kno( (eter tere are oter spae-&arin) i'iliations in te ilk *a$ I& te do eCist, (e do not kno( o( ab8ndant te are, m8 less (ere te are$ B8t tere is at least a ane tat sometime in te remote &8t8re one o& te Vo$agers (ill be interepted and eCamined b an alien ra&t$ ordin)l, as ea Vo$ager le&t Eart &or te planets and te stars, it arried (it it a )olden pono)rap reord enased in a )olden, mirrored Haket ontainin), amon) oter tin)s? )reetin)s in 59 8man lan)8a)es and one (ale lan)8a)e? a 1"-min8te so8nd essa inl8din) a kiss, a babAs r, and an EE/ reord o& te meditations o& a o8n) (oman in lo'e? 116 enoded pit8res, on o8r siene, o8r i'iliation, and o8rsel'es? and 90 min8tes o& te EartAs )reatest itsGEastern and *estern, lassial and &olk, inl8din) a Na'aHo ni)t ant, a >apanese
akua7i piee, a )m )irlAs initiation son), a er8'ian (eddin) son), a 3,000-ear-old omposition &or te 7in alled %lo(in) Streams, Ba, Beeto'en, oart, Stra'insk, .o8is rmstron), Blind *illie >onson, and +8k BerrAs >onn B$ /oode$ Spae is nearl empt$ ere is 'irt8all no ane tat one o& te Vo$agers (ill e'er enter anoter solar sstemGa nd tis is tr8e e'en i& e'er star in te sk is aompanied b planets$ e instr8tions on te reord Hakets, (ritten in (at (e belie'e to be readil ompreensible sienti&i iero)lpis, an be read, and te ontents o& te reords 8nderstood, onl i& alien bein)s, some(ere in te remote &8t8re, &ind Vo$ager in te depts o& interstellar spae$ Sine bot Vo$agers (ill irle te enter o& te ilk *a /alaC essentiall &ore'er, tere is plent o& time &or te reords to be &o8ndGi& tereAs anone o8t tere to do te &indin)$ *e annot kno( o( m8 o& te reords te (o8ld 8nderstand$ S8rel te )reetin)s (ill be inompreensible, b8t teir intent ma not be$ =*e to8)t it (o8ld be impolite not to sa ello$< e potetial aliens are bo8nd to be 'er di&&erent &rom 8sGindependentl e'ol'ed on anoter (orld$ re (e reall s8re te o8ld 8nderstand antin) at all o& o8r messa)eD E'er time I &eel tese onerns stirrin), to8), I reass8re msel&$ *ate'er te inompreensibilities o& te Vo$ager reord, an alien sip tat &inds it (ill a'e anoter standard b (i to H8d)e 8s$ Ea Vo$ager is itsel& a messa)e$ In teir eCplorator intent, in te lo&t ambition o& teir obHeti'es, in teir 8tter lak o& intent to do arm, and in te brilliane o& teir desi)n and per&ormane, tese robots speak eloK8entl &or 8s$ B8t bein) m8 more ad'aned sientists and en)ineers tan (eGoter(ise te (o8ld ne'er be able to &ind and retrie'e te small, silent spaera&t in interstellar spaeGperaps te aliens (o8ld a'e no di&&i8lt 8nderstandin) (at is enoded on tese )olden reords$ eraps te (o8ld reo)nie te tentati'eness o& o8r soiet, te mismat bet(een o8r tenolo) and
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o8r (isdom$ a'e (e destroed o8rsel'es sine la8nin) Vo$agerte mi)t (onder, or a'e (e )one on to )reater tin)sD 2r peraps te reords (ill ne'er be interepted$ eraps no one in &i'e billion ears (ill e'er ome 8pon tem$ %i'e billion ears is a lon) time$ In &i'e billion ears, all 8mans (ill a'e beome eCtint or e'ol'ed into oter bein)s, none o& o8r arti&ats (ill a'e s8r'i'ed on Eart, te ontinents (ill a'e beome 8nreo)niabl altered or destroed, and te e'ol8tion o& te S8n (ill a'e b8rned te Eart to a risp or red8ed it to a (irl o& atoms$ %ar &rom ome, 8nto8ed b tese remote e'ents, te Vo$agers, bearin) te memories o& a (orld tat is no more, (ill &l on$
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S+E! B.+ !eep sk is, o& all 'is8al impressions, te nearest akin to a &eelin)$ @SAME& /A,&O #O&E!.%E O/E>OODS (1805)
Te bl8e o& a lo8dless a mornin), or te reds and oran)es o& a s8nset at sea, a'e ro8sed 8mans to (onder, to poetr, and to siene$ No matter (ere on Eart (e li'e, no matter (at o8r lan)8a)e, 8stoms, or politis, (e sare a sk in ommon$ ost o& 8s expect tat a8re bl8e and (o8ld, &or )ood reason, be st8nned to (ake 8p one s8nrise to &ind a lo8dless sk tat (as blak or ello( or )reen$ =Inabitants o& .os n)eles and eCio +it a'e )ro(n a8stomed to bro(n skies, and tose o& .ondon and Seattle to )ra onesGb8t e'en te still onsider bl8e te planetar norm$< nd et tere are (orlds (it blak or ello( skies, and mabe e'en )reen$ e olor o& te sk arateries te (orld$ lop me do(n on an planet in te Solar Sstem? (ito8t sensin) te )ra'it, (ito8t )limpsin) te )ro8nd, let me take a K8ik look at te S8n and sk, and I an, I tink, prett (ell tell o8 (ere I am$ at &amiliar sade o& bl8e, interr8pted ere and tere b &lee (ite lo8ds, is a si)nat8re o& o8r (orld$ e %ren a'e an eCpression, a7re-;leuB (i translates ro8)l as /ood ea'ensF 1 .iterall, it means sared bl8eF 1
.ike )os-darned and )ee, tis prase (as ori)inall a e8pemism &or tose (o onsidered Sacre-Dieu!, Sared /odF,
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Indeed$ I& tere e'er is a tr8e &la) o& Eart, tis so8ld be its olor$ Birds &l tro8) it, lo8ds are s8spended in it, 8mans admire and ro8tinel tra'erse it, li)t &rom te S8n and stars &l8tters tro8) it$ B8t (at is itD *at is it made o&D *ere does it endD o( m8 o& it is tereD *ere does all tat bl8e ome &romD I& itAs a ommonplae &or all 8mans, i& it tpi&ies o8r (orld, s8rel (e so8ld kno( sometin) abo8t it$ *at is te skD In 8)8st 1957, &or te &irst time, a 8man bein) rose abo'e te bl8e and looked aro8ndG (en !a'id Simons, a retired ir %ore o&&ier and a psiian, beame te i)est 8man in istor$ lone, e piloted a balloon to an altit8de o& o'er 100,000 &eet =30 kilometers< and tro8) is tik (indo(s )limpsed a di&&erent sk$ No( a pro&essor at te ni'ersit o& +ali&ornia edial Sool in Ir'ine, !r$ Simons realls it (as a dark, deep p8rple o'eread$ e ad reaed te transition re)ion (ere te bl8e o& )ro8nd le'el is bein) o'ertaken b te per&et blak o& spae$ Sine SimonsA almost &or)otten &li)t, people o& man nations a'e &lo(n abo'e te atmospere$ It is no( lear &rom repeated and diret 8man =and roboti< eCperiene tat in spae te datime sk is blak$ e S8n sines bri)tl on o8r sip$ e Eart belo( o8 is brilliantl ill8minated$ B8t te sk abo'e is blak as ni)t$ ere is te memorable desription b 8ri /a)arin o& (at e sa( on te &irst spae&li)t o& te 8man speies, aboard Vo"ok 1, on pril 1", 1961:
e sk is ompletel blak? and a)ainst te bak)ro8nd o& tis blak sk te stars appear some(at bri)ter and more distint$ e Eart as a 'er arateristi, 'er bea8ti&8l bl8e alo, (i is seen (ell (en o8 obser'e te orion$ ere is a smoot olor transition &rom tender bl8e, to bl8e, to dark bl8e and p8rple, and ten to te ompletel blak olor o& te sk$ It is a 'er bea8ti&8l transition$
+learl, te dalit skGall tat bl8eG is someo( onneted (it te air$ B8t as o8 look aross te break&ast table, o8r ompanion is not =8s8all< bl8e? te olor o& te sk m8st be a propert not o& a little air, b8t o& a )reat deal$ I& o8 look losel at te Eart &rom spae, o8 see it s8rro8nded b a tin band o& bl8e, as tik as te lo(er atmospere? indeed, it is te lo(er atmospere$ tetransition top o& tat band o8 an make sk &adin) into tete blakness spae$ is istte one tat Simons (as o8t te te &irstbl8e to enter and /a)arin &irst to o& obser'e &rom abo'e$ In ro8tine spae&li)t, o8 start at te bottom o& te bl8e, penetrate entirel tro8) it a &e( min8tes a&ter li&to&&? and ten enter tat bo8ndless realm (ere a simple breat o& air is impossible (ito8t elaborate li&e-s8pport sstems$ 8man li&e depends &or its 'er eCistene on tat bl8e sk$ *e are ri)t to onsider it tender and sared$ *e see te bl8e in datime bea8se s8nli)t is bo8nin) o&& te air aro8nd and abo'e 8s$ 2n a lo8dless ni)t, te sk is blak bea8se tere is no s8&&iientl intense so8re o& li)t to be re&leted o&& te air$ Someo(, te air pre&erentiall bo8nes bl8e li)t do(n to 8s$ o(D e 'isible li)t &rom te S8n omes in man olorsG'iolet, bl8e, )reen, ello(, oran)e, redGorrespondin) to li)t o& di&&erent (a'elen)ts$ = (a'elen)t is te distane &ront rest to too stron) an oat, te Seond +ommandment d8l onsidered, to be 8ttered alo8d$
;1
rest as te (a'e tra'els tro8) air or spae$< #iolet and bl8e li)t (a'es a'e te sortest (a'elen)ts? oran)e and red te lon)est$ *at (e perei'e as olor is o( o8r ees and brains read te (a'elen)ts o& li)t$ =*e i)t H8st as reasonabl translate (a'elen)ts o& li)t into, sa, eard tones rater tan seen olorsGb8t tatAs not o( o8r senses e'ol'ed$< *en all tose rainbo( olors o& te spetr8m are miCed to)eter, as in s8nli)t, te seem almost (ite$ ese (a'es tra'el to)eter in ei)t min8tes aross te inter'enin) 93 million miles =150 million kilometers< o& spae &rom te S8n to te Eart$ e strike te atmospere, (i is made mostl o& nitro)en and oC)en mole8les$ Some (a'es are re&leted b te air bak into spae$ Some are bo8ned aro8nd be&ore te li)t reaes te )ro8nd and te an be deteted b a passin) eeball$ =lso, some bo8ne o&& lo8ds or te )ro8nd bak into spae$< is bo8nin) aro8nd o& li)t (a'es in te atmospere is alled satterin)$ B8t not all (a'es are eK8all (ell sattered b te mole8les o& air$ *a'elen)ts tat are m8 lon)er tan te sie o& te mole8les are sattered less? te spill o'er te mole8les, ardl in&l8ened b teir presene$ *a'elen)ts tat are loser to te sie o& te mole8les are sattered snore$ nd (a'es a'e tro8ble i)norin) obstales as bi) as te are$ =o8 an see tis in (ater (a'es sattered b te pilin)s o& piers, or batt8b (a'es &rom a drippin) &a8et eno8nterin) a r8bber d8k$< e sorter (a'elen)ts, tose tat (e sense as 'iolet and bl8e li)t, are more e&&iientl sattered tan te lon)er (a'elen)ts, tose tat (e sense as oran)e and red li)t$ *en (e look 8p on a lo8dless da and admire te bl8e sk, (e are (itnessin) te pre&erential satterin) o& te sort (a'es in s8nli)t$ is is alled alei) satterin), a&ter te En)lis psiist (o o&&ered te &irst oerent eCplanation &or it$ +i)arette smoke is bl8e &or H8st te same reason: e partiles tat make it 8p are abo8t as small as te (a'elen)t o& bl8e li)t$ So ( is te s8nset redD e red o& te s8nset is (atAs le&t o& s8nli)t a&ter te air satters te bl8e a(a$ Sine te atmospere is a tin sell o& )ra'itationall bo8nd )as s8rro8ndin) te solid Eart, s8nli)t m8st pass tro8) a lon)er slant pat o& air at s8nset =or s8nrise< tan at noon$ Sine te 'iolet and bl8e (a'es are sattered e'en more d8rin) teir no(-lon)er pat tro8) te air tan (en te S8n is o'eread, (at (e see (en (e look to(ard te S8n is te resid8eGte (a'es o& s8nli)t tat are ardl sattered a(a at all, espeiall te oran)es and reds$ bl8e sk makes a red s8nset$ =e noontime S8n seems ello(is partl bea8se it emits sli)tl more ello( li)t tan oter olors, and partl bea8se, e'en (it te S8n o'eread, some bl8e li)t is sattered o8t o& te s8nbeams b te EartAs atmospere$< It is sometimes said tat sientists are 8nromanti, tat teir passion to &i)8re o8t robs te (orld o& bea8t and mster$ B8t is it not stirrin) to 8nderstand o( te (orld at8all (orksG tat (ite li)t is made o& olors, tat olor is te (a (e perei'e te (a'elen)ts o& li)t, tat transparent air re&lets li)t, tat in so doin) it disriminates amon) te (a'es, and tat te sk is bl8e &or te same reason tat te s8nset is redD It does no arm to te romane o& te s8nset to kno( a little bit abo8t it$ Sine most simple mole8les are abo8t te same sie =ro8)l a 8ndred milliont o& a entimeter<, te bl8e o& te EartAs sk doesnAt m8 depend on (at te air is made o&Gas lon) as te air doesnAt a;or; te li)t$ 2C)en and nitro)en mole8les donAt absorb 'isible li)t? te onl bo8ne it a(a in some oter diretion$ 2ter mole8les, to8), an )obble 8p te li)t$ 2Cides o& nitro)enGprod8ed in a8tomoti'e en)ines and in te &ires o& ind8strGare a
;"
so8re o& te m8rk bro(n oloration o& smo)$ 2Cides o& nitro)en =made &rom oC)en and nitro)en< do absorb li)t$ bsorption, as (ell as satterin), an olor a sk$ OTHER WORLDS, OTHER SKIES:er8r,
te EartAs oon, and most satellites o& te oter planets are small (orlds? bea8se o& teir &eeble )ra'ities, te are 8nable to retain teir atmosperesG(i instead trikle o& into spae$ e near-'a88m o& spae ten reaes te )ro8nd$ S8nli)t strikes teir s8r&aes 8nimpeded, neiter sattered nor absorbed alon) te (a$ e skies o& tese (orlds are blak, e'en at noon$ is as been (itnessed &irstand so &ar b onl 1" 8mans, te l8nar landin) re(s o& Apollo 11, 12, and 1F-1*$ &8ll list o& te satellites in te Solar Sstem, kno(n as o& tis (ritin), is )i'en in te aompanin) table$ =Nearl al& o& tem (ere diso'ered b Vo$ager3) ll a'e blak skiesG eCept itan o& Sat8rn and peraps riton o& Nept8ne, (i are bi) eno8) to a'e atmosperes$ nd all asteroids as (ell$ #en8s as abo8t 90 times more air tan Eart$ It isnAt mainl oC)en and nitro)en as ereG itAs arbon dioCide$ B8t arbon dioCide doesnAt absorb 'isible li)t eiter$ *at (o8ld te sk look like &rom te s8r&ae o& #en8s i& #en8s ad no lo8ds$ *it so m8 atmospere in te (a, not onl are 'iolet and bl8e (a'es sattered, b8t all te oter olors as (ell-)reen ello(, oran)e, red$ e air is so tik, to8), tat ardl an bl8e li)t makes it to te )ro8nd? itAs sattered bak to spae b s8essi'e bo8nes i)er 8p$ 8s, te li)t tat does rea te )ro8nd so8ld be stron)l reddened-like an Eart s8nset all o'er te sk$ %8rter, s8l&8r in te i) lo8ds (ill stain te sk ello($ it8res taken b te So'iet Venera landers on&irm tat te skies o& #en8s are a kind o& ello(-oran)e$ SI-*2 *2.!S %2 E I! I..ENNI: N2*N 22NS 2% E .NES =N! 2NE SE2I!
EAR TH, MAR S, ! IDA , JUP ITE R, " SATURN, # URA NUS, $ NEP TUN E, # PLU T%,
oon
obos !eimos
!atl etis drastea maltea ebe to E8ropa /anmede +allisto .eda imalia .sitea Elara nanke +arme asipae Sinope
an tlas romete8s andora
+ordelia 2pelia Biana +ressida
Epimete8s >an8s imas Enelad8s ets elesto +alpso !iane elene ea itan perion Iapet8s oebe
!esdemona >8liet ortia osalind Belinda 8k iranda riel mbriel itania 2beron
;3
Naiad alassa !espina /alatea .arissa rote8s riton Nereid
+aron
ars is a di&&erent stor$ It is a smaller (orld tan Eart, (it a m8 tinner atmospere$ e press8re at te s8r&ae o& ars is, in &at, abo8t te same as te altit8de in te EartAs stratospere to (i Simons rose$ So (e mi)t eCpet te artian sk to be blak or p8rpleblak$ e &irst olor pit8re &rom te s8r&ae o& ars (as obtained in >8l 1976 b te merian Viking 1 landerGte &irst spaera&t to to8 do(n s8ess&8ll on te s8r&ae o& te ed lanet$ e di)ital data (ere d8ti&8ll radioed &rom ars bak to Eart, and te olor pit8re assembled b omp8ter$ o te s8rprise o& all te sientists and nobod else, tat &irst ima)e, released to te press, so(ed te artian sk to be a om&ortable, ome bl8eG impossible &or a planet (it so ins8bstantial an atmospere$ Sometin) ad )one (ron)$ e pit8re on o8r olor tele'ision set is a miCt8re o& tree monorome ima)es, ea in a di&&erent olor o& li)tGred, )reen, and bl8e$ o8 an see tis metod o& olor ompositin) in 'ideo proHetion sstems, (i proHet separate beams o& red, )reen, and bl8e li)t to )enerate a &8ll-olor pit8re =inl8din) ello(s<$ o )et te ri)t olor, o8r set needs to miC or balane tese tree monorome ima)es orretl$ I& o8 t8rn 8p te intensit o&, sa, bl8e, te pit8re (ill appear too bl8e$ n pit8re ret8rned &rom spae reK8ires a similar olor balane$ +onsiderable disretion is sometimes le&t to te omp8ter analsts in deidin) tis balane$ e hiking analsts (ere not planetar astronomers, and (it tis &irst olor pit8re &rom ars te simpl miCed te olors 8ntil it looked ri)t$ *e are so onditioned b o8r eCperiene on Eart tat ri)t, o& o8rse, means a bl8e sk$ e olor o& te pit8re (as soon orretedG 8sin) olor alibration standards plaed &or tis 'er p8rpose on board te spaera&tGand te res8ltin) omposite so(ed no bl8e sk at all? rater it (as sometin) bet(een ore and pink$ Not bl8e, b8t ardl p8rple-blak eiter$ is is te ri)t olor o& te artian sk$ 8 o& te s8r&ae o& ars is desertGand red bea8se te sands are r8sk$ ere are oasional 'iolent sandstorms tat li&t &ine partiles &rom te s8r&ae i) into te atmospere$ It takes a lon) time &or tem to &all o8t, and be&ore te sk as &8ll leaned itsel&, tereAs al(as anoter sandstorm$ /lobal or near-)lobal sandstorms o8r almost e'er artian ear$ Sine r8st partiles are al(as s8spended in tis sk, &8t8re )enerations o& 8mans, born and li'in) o8t teir li'es on ars, (ill onsider tat salmon olor to be as nat8ral and &amiliar as (e onsider o8r ome bl8e$ %rom a sin)le )lane at te datime sk, teAll probabl be able to tell o( lon) itAs been sine te last bi) sandstorm$ e planets in te o8ter Solar SstemG>8piter, Sat8rn, ran8s, and Nept8neG are o& a di&&erent sort$ ese are 8)e (orlds (it )iant atmosperes made mainl o& dro)en and eli8m$ eir solid s8r&aes are so deep inside tat no s8nli)t penetrates tere at all$ !o(n tere, te sk is blak, (it no prospet o& a s8nriseGnot e'er$ e perpet8al starless ni)t is peraps ill8minated on oasion b a bolt o& li)tnin)$ B8t i)er in te atmospere, (ere te s8nli)t reaes, a m8 more bea8ti&8l 'ista a(aits$ 2n >8piter, abo'e a i)-altit8de ae laer omposed o& ammonia =rater tan (ater< ie partiles, te sk is almost blak$ %arter do(n, in te bl8e sk re)ion, are m8ltiolored lo8ds Gin 'ario8s sades o& ello(-bro(n, and o& 8nkno(n omposition$ =e andidate materials inl8de s8l&8r, pospor8s, and ompleC or)ani mole8les$< E'en &arter do(n, te sk (ill appear red-bro(n, eCept tat te lo8ds tere are o& 'arin) tiknesses, and (ere te are tin, o8 mi)t see a pat o& bl8e$ Still deeper, (e )rad8all ret8rn to perpet8al ni)t $
;4
Sometin) similar is tr8e on Sat8rn, b8t te olors tere are more m8ted$ ran8s and espeiall Nept8ne a'e an 8nann, a8stere bl8e olor tro8) (i lo8dsG some o& tem a little (iterGare arried b i)-speed (inds$ S8nli)t reaes a omparati'el lean atmospere omposed mainl o& dro)en and eli8m b8t also ri in metane$ .on) pats o& metane absorb ello( and espeiall red li)t and let te )reen and bl8e &ilter tro8)$ tin droarbon ae remo'es a little bl8e$ ere ma be a dept (ere te sk is )reenis$ +on'entional (isdom olds tat te absorption b metane and te alei) satterin) o& s8nli)t b te deep atmospere to)eter ao8nt &or te bl8e olors on ran8s and Nept8ne$ B8t analsis o& Vo$ager data b e'in Baines o& >. seems to so( tat tese a8ses are ins8&&iient$ pparentl 'er deepGmabe in te 'iinit o& potesied lo8ds o& dro)en s8l&ideGtere is an ab8ndant bl8e s8bstane$ So &ar no one as been able to &i)8re o8t (at it mi)t be$ Bl8e materials are 'er rare in Nat8re$ s al(as appens in siene, te old msteries are dispelled onl to be replaed b ne( ones$ Sooner or later (eAll &ind o8t te ans(er to tis one, too$
ALL WORLDS WITH NONBLACK SKIESa'e
atmosperes$ I& o8Are standin) on te s8r&ae and tereAs an atmospere tik eno8) to see, tereAs probabl a (a to y tro8) it$ *eAre no( sendin) o8r instr8ments to &l in te 'ario8sl olored skies o& oter (orlds$ Someda (e (ill )o o8rsel'es$ ara8tes a'e alread been 8sed in te atmosperes o& #en8s and ars, and are planned &or >8piter and itan$ In 19;5 t(o %ren-So'iet balloons sailed tro8) te ello( skies o& #en8s$ e Vega 9 balloon, abo8t 4 meters aross, dan)led an instr8ment paka)e 13 meters belo($ e balloon in&lated in te ni)t emispere, &loated abo8t 54 kilometers abo'e te s8r&ae, and transmitted data &or almost t(o Eart das be&ore its batteries &ailed$ In tat time it tra'eled 11,600 kilometers =nearl 7,000 miles< o'er te s8r&ae o& #en8s, &ar belo($ e Vega 2 balloon ad an almost idential pro&ile$ e atmospere o& #en8s as also been 8sed &or aerobrakin)Gan)in) te Magellan spaera&tAs orbit b &rition (it te dense air? tis is a ke &8t8re tenolo) &or on'ertin) &lb spaera&t to ars into orbiters and landers$ ars mission, sed8led to be la8ned in 199;, and led b 8ssia, inl8des an enormo8s %ren ot air balloonGlookin) sometin) like a 'ast Hell&is, a ort8)8ese man-o&(ar$ ItAs desi)ned to sink to te artian s8r&ae e'er ill t(ili)t and rise i) (en eated b s8nli)t te neCt da$ e (inds are so &ast tat, i& all )oes (ell, it (ill be arried 8ndreds o& kilometers ea da, oppin) and skippin) o'er te nort pole$ In te earl mornin), (en lose to te )ro8nd, it (ill obtain 'er i) resol8tion pit8res and oter data$ e balloon as an instr8mental )8ide-rope, essential &or its stabilit, onei'ed and desi)ned b a pri'ate membersip or)aniation based in asadena, +ali&ornia, e lanetar Soiet$ Sine te s8r&ae press8re on ars is approCimatel tat at an altit8de o& 100,000 &eet on Eart, (e kno( (e an &l airp lanes tere$ e -", &or eCample, or te S-71 >la7k;ir ro8tinel approaes s8 lo( press8res$ irra&t (it e'en lar)er (in)spans a'e been desi)ned &or ars$ e dream o& &li)t and te dream o& spae tra'e l are t(ins , onei'ed b similar 'isionaries, dependent on allied tenolo)ies, and e'ol'in) more or less in tandem$ s ertain
;5
pratial and eonomi limits to &li)t on Eart are reaed, te possibilit arises o& &lin) tro8) te m8lti8ed skies o& oter (orlds$ IT IS NOW ALMOST POSSIBLE to
assi)n olor ombinations, based on te olors o& lo8ds and sk, to e'er planet in te Solar SstemG&rom te s8l&8r-stained skies o& #en8s and te r8st skies o& ars to te aK8amarine o& ran8s and te pnoti and 8neartl bl8e o& Nept8ne$ Sa7re-aun" a7re-rouge a7re-4er"3eraps te (ill one da adorn te &la)s o& distant 8man o8tposts in te Solar Sstem, in tat time (en te ne( &rontiers are s(eepin) o8t &rom te S8n to te stars, and te eCplorers are s8rro8nded b te endless blak o& spae$ Sa7re-noir3
C
H
A
P
T
E
R
11
E#ENIN/ N! 2NIN/ S is is anoter (orld *i is not o& men$ G.I BI, TESI2N N! NS*E IN E 2NINS =+IN, N/ !NS, +$ 730<
Yo8 an see it sinin) brilliantl in te t(ili)t, asin) te S8n do(n belo( te (estern orion$ pon &irst )limpsin) it ea ni)t, people (ere a8stomed to make a (is =8pon a star<$ Sometimes te (is ame tr8e$ 2r o8 an sp it in te east be&ore da(n, &leein) te risin) S8n$ In tese t(o inarnations, bri)ter tan antin) else in te sk eCept onl te S8n and te oon it (as kno(n as te e'enin) and te mornin) star$ 28r anestors did not reo)nie it (as a (orld, te
;6
same (orld, ne'er too &ar &rom te S8n bea8se it is in an orbit abo8t it interior to te EartAs$ >8st be&ore s8nset or H8st a&ter s8nrise, (e an sometimes see it near some &l8&& (ite lo8d, and ten diso'er b te omparison tat #en8s as a olor, a pale lemon-ello($ o8 peer tro8) te eepiee o& a telesopeGe'en a bi) telesope, e'en te lar)est optial telesope on EartGand o8 an make o8t no detail at all$ 2'er te monts, o8 see a &eat8reless disk metodiall )oin) tro8) pases, like te oon: resent #en8s, &8ll #en8s, )ibbo8s #en8s, ne( #en8s$ ere is not a int o& ontinents or oeans$ Some o& te &irst astronomers to see #en8s tro8) te telesope immediatel reo)nied tat te (ere eCaminin) a (orld ensro8ded b lo8ds$ e lo8ds, (e no( kno(, are droplets o& onentrated s8l&8ri aid, stained ello( b a little elemental s8l&8r$ e lie i) abo'e te )ro8nd$ In ordinar 'isible li)t tereAs no int o& (at tis planetAs s8r&ae, some 50 kilometers belo( te lo8d tops, is like, and &or ent8ries te best (e ad (ere (ild )8esses$ o8 mi)t onHet8re tat i& (e o8ld take a m8 &iner look tere mi)t be breaks in te lo8ds, re'ealin) da b da, in bits and piees, te msterio8s s8r&ae ordinaril idden &rom o8r 'ie($ en te time o& )8esses (o8ld be o'er$ e Eart is on a'era)e al& lo8d-o'ered$ In te earl das o& #en8s eCploration, (e sa( no reason tat #en8s so8ld be 100 perent o'erast$ I& instead it (as onl 90 perent, or e'en 99 perent, lo8d-o'ered, te transient pates o& learin) mi)t tell 8s m8$ In 1960 and 1961, Mariner 1 and ", te &irst merian spaera&t desi)ned to 'isit #en8s, (ere bein) prepared$ ere (ere tose, like me, (o to8)t te sips so8ld arr 'ideo ameras so te o8ld radio pit8res bak to Eart$ e same tenolo) (o8ld be 8sed a &e( ears later (en anger * 8 and 9 (o8ld poto)rap te oon on te (a to teir ras landin)sGte last makin) a b8llAs-ee in te rater lpons8s$ B8t time (as sort &or te #en8s mission, and ameras (ere ea'$ ere (ere tose (o maintained tat ameras (erenAt reall sienti&i instr8ments, b8t rater at-as-at-an, rale-dale, panderin) to te p8bli, and 8nable to ans(er a sin)le strai)t&or(ard, (ell-posed sienti&i K8estion$ I to8)t msel& tat (eter tere are breaks in te lo8ds (as one s8 K8estion$ I ar)8ed tat ameras o8ld also ans(er K8estions tat (e (ere too d8mb e'en to pose$ I ar)8ed tat pit8res (ere te onl (a to so( te p8bliG(o (ere, a&ter all, &ootin) te billGte eCitement o& roboti missions$ t an rate, no amera (as &lo(n, and s8bseK8ent missions a'e, &or tis parti8lar (orld, at least partl 'indiated tat H8d)ment: E'en at i) resol8tion &rom lose &lbs, in 'isible li)t it t8rns o8t tere are no breaks in te lo8ds o& #en8s, an more tan in te lo8ds o& itan$1 ese (orlds are permanentl o'erast$ In te 8ltra'iolet tere is detail, b8t d8e to transient pates o& i)-altit8de o'erast, &ar abo'e te main lo8d dek$ e i) lo8ds rae aro8nd te planet m8 &aster tan te planet itsel& t8rns: s8per-rotation$ *e a'e an e'en smaller ane o& seein) te s8r&ae in te 8ltra'iolet$ *en it beame lear tat te atmospere o& #en8s (as m8 tiker tan te air on Eart Gas (e no( kno(, te press8re at te s8r&ae is ninet times (at it is ereGit immediatel 1
%or itan, ima)in) re'ealed a s8ession o& detaed aes abo'e te main laer o& aerosols$ So #en8s (orks o8t to be te onl (orld in te Solar Sstem &or (i spaera&t ameras (orkin) in ordinar 'isible li)t a4en" diso'ered sometin) important$ Explorer (i raed appil, (eA'e no( ret8rned pit8res &rom almost e'er (orld (eA'e 'isited$ =NSAs International +ometar tro8) te tail o& +omet /iaobini-@immer in 19;5, &le( blind, be de'oted to ar)ed partiles and ma)neti &ields$<
;7
&ollo(ed tat in ordinar 'isible li)t (e o8ld not possibl see te s8r&ae, e'en i& tere im ollak, !a'e orrison, and I (ent to te !onald 2bser'ator o& te ni'ersit o& eCas to tr to obser'e #en8s in te near-in&rared$ *e persensitied o8r em8lsions? te )ood old-&asioned 1 )lass poto)rapi plates (ere treated (it ammonia, and sometimes eated or brie&l ill8minated, be&ore bein) eCposed at te telesope to li)t &rom #en8s$ %or a time te ellars o& !onald 2bser'ator reeked o& ammonia$ *e took man pit8res$ None so(ed an detail$ *e onl8ded tat eiter (e adnAt )one &ar eno8) into te in&rared or te lo8ds o& #en8s (ere opaK8e and 8nbroken in te near in&rared$ ore tan "0 ears later, te %alileo spaera&t, makin) a lose &lb o& #en8s, eCamined it (it i)er resol8tion and sensiti'it, and at (a'elen)ts a little &8rter into te in&rared tan (e (ere able to rea (it o8r r8de )lass em8lsions$ %alileo poto)raped )reat mo8ntain ran)es$ *e alread kne( o& teir eCistene, to8)? a m8 more po(er&8l teniK8e ad earlier been emploed: radar$ adio (a'es e&&ortlessl penetrate te lo8ds and tik atmospere o& #en8s, bo8ne o&& te s8r&ae, and ret8rn to Eart, (ere te are )atered in and 8sed to make a pit8re$ e &irst (ork ad been done, ie&l, b$ merian )ro8nd-based radar at >.As /oldstone trakin) station in te oHa'e !esert and at te reibo 2bser'ator in 8erto io, operated b +ornell ni'ersit$ en te $S$ Pioneer 12 te So'iet Venera 15 and D6 an d te $S $ Magellan missions inserted radar telesopes into orbit aro8nd #en8s and mapped te plae pole to pole$ Ea spaera&t (o8ld transmit a radar si)nal to te s8r&ae and ten at it as it bo8ned bak$ %rom o( re&leti'e ea pat o& s8r&ae (as and o( lon) it took te si)nal to ret8rn =sorter &rom mo8ntains, lon)er &rom 'alles<, a detailed map o& te entire s8r&ae (as slo(l and painstakin)l onstr8ted$ e (orld so re'ealed t8rns o8t to be 8niK8el s8lpted b la'a &lo(s =and, to a m8 lesser de)ree, b (ind<, as desribed in te neCt apter$ e lo8ds and atmospere o& #en8s a'e no( beome transparent to 8s, and anoter (orld as been 'isited b te do8)t robot eCplorers &rom Eart$ 28r eCperiene (it #en8s is no( bein) applied else(ereGespeiall to itan, (ere one a)ain impenetrable lo8ds ide an eni)mati s8r&ae, and radar is be)innin) to )i'e 8s ints o& (at mi)t lie belo($
1
oda man telesopi ima)es are obtained (it s8 eletroni ontri'anes as ar)e-o8pled de'ies and diode arras, and proessed b omp8terGall tenolo)ies 8na'ailable to astronomers in 1970$
;;
VENUS HAD LONG BEEN THOUGHTo&
as o8r sister (orld$ It is te nearest planet to te Eart$ It
as almost te same mass, sie, densit, and )ra'itational p8ll as te Eart does$ ItAs a little loser to te S8n tan te Eart, b8t its bri)t lo8ds re&let more s8nli)t bak to spae tan o8r lo8ds do$ s a &irst )8ess o8 mi)t 'er (ell ima)ine tat, 8nder tose 8nbroken lo8ds, #en8s (as rater like Eart$ Earl sienti&i spe8lation inl8ded &etid s(amps ra(lin) (it monster ampibians, like te Eart in te +arboni&ero8s eriod? a (orld desert? a )lobal petrole8m sea? and a selter oean dotted ere and tere (it limestone-enr8sted islands$ *ile based on some sienti&i data, tese Pmodels o& #en8sGte &irst datin) &rom te be)innin)s o& te ent8r, te seond &rom te 1930s, and te last t(o &rom te raid-1950sG(ere little more tan sienti&i romanes, ardl onstrained b te sparse data a'ailable$ en, in 1956, a report (as p8blised in /e A"rop$i7al Gournal b +ornell $ aer and is ollea)8es$ e ad pointed a ne(l ompleted radio telesope, b8ilt in part &or lassi&ied resear, on te roo& o& te Na'al esear .aborator in *asin)ton, !$+$, at #en8s and meas8red te &l8C o& radio (a'es arri'in) at Eart$ is (as not radar: No radio (a'es (ere bo8ned o&& #en8s$ is (as listenin) to radio (a'es tat #en8s on its o(n emits to spae$ #en8s t8rned o8t to be m8 bri)ter tan te bak)ro8nd o& distant stars and )alaCies$ is in itsel& (as not 'er s8rprisin)$ E'er obHet (armer tan absol8te ero =-"73U+< )i'es o&& radiation tro8)o8t te eletroma)neti spetr8m, inl8din) te radio re)ion$ o8, &or eCample, emit radio (a'es at an e&&eti'e or bri)tness temperat8re o& abo8t 35U+, and i& o8 (ere in s8rro8ndin)s older tan o8 are, a sensiti'e radio telesope o8ld detet te &aint radio (a'es o8 are transmittin) in all diretions$ Ea o& 8s is a so8re o& old stati$ *at
;9
(ater droplets in te #en8s lo8ds (ere s8))ested$ )lo( disar)e in (i ions and eletrons reombined at t(ili)t and da(n in te 8pper atmospere (as o&&ered$ 'er dense ionospere ad its ad'oates, in (i te m8t8al aeleration o& 8nbo8nd eletrons =&ree-&ree emission< )a'e o&& radio (a'es$ =2ne proponent o& tis idea e'en s8))ested tat te i) ioniation reK8ired (as d8e to an a'era)e o& 10,000 times )reater radioati'it on #en8s tan on EartG peraps &rom a reent n8lear (ar tere$< nd, in te li)t o& te diso'er o& radiation &rom >8piterAs ma)netospere, it (as nat8ral to s8))est tat te radio emission ame &rom an immense lo8d o& ar)ed partiles trapped b some potetial 'er intense #en8sian ma)neti &ield$ In a series o& papers I p8blised in te middle 1960s, man in ollaboration (it >im ollak,1 tese on&litin) models o& a i) ot emitt in) re)io n and a old s8r&ae (ere s8bHeted to a ritial analsis$ B ten (e ad t(o important ne( l8es: te radio spetr8m o& #en8s, and te Mariner 2 e'idene tat te radio emission (as more intense at te enter o& te disk o& #en8s tan to(ard its ed)e$ B 1967 (e (ere able to eCl8de te alternati'e models (it some on&idene, and onl8de tat te s8r&ae o& #en8s (as at a sorin) and 8n-Eartlike temperat8re, in eCess o& 400U+$ B8t te ar)8ment (as in&erential, and tere (ere man intermediate steps$ *e lon)ed &or a more diret meas8rement$ In 2tober 1967Gommemoratin) te tent anni'ersar o& Spu"nik 1Gte So'iet Venera F spaera&t dropped an entr aps8le into te lo8ds o& #en8s$ It ret8rned data &rom te ot lo'er atmospere, b8t did not s8r'i'e to te s8r&ae$ 2ne da later, te nited States spaera&t
Mariner 5 &le( b #en8s, its radio transmission to Eart skimmin) te atmospere at pro)ressi'el )reater depts$ e rate o& &adin) o& te si)nal )a'e
in&ormation abo8t
atmosperi temperat8res$ lto8) tere seemed to be some disrepanies =later resol'ed< bet(een te t(o sets o& spaera&t data, bot learl indiated tat te s8r&ae o& #en8s is 'er ot$ Sine ten a pro)ression o& So'iet Venera spaera&t and one l8ster o& merian spaera&t &rom te Pioneer 12 mission a'e entered te deep atmospere or landed on te s8r&ae and meas8red diretlGessentiall b stikin) o8t a termometerGte s8r&ae and near-s8r&ae temperat8res$ e t8rn o8t to be abo8t 470U+, almost 900U%$ *en s8 &ators as alibration errors o& terrestrial radio telesopes and s8r&ae emissi'it are taken into ao8nt, te old radio obser'ations and te ne( diret spaera&t meas8rements t8rn o8t to be in )ood aord$ Earl So'iet landers (ere desi)ned &or an atmospere some(at like o8r o(n$ e (ere r8sed b te i) press8res like a tin an in te )rasp o& a ampion arm (restler, or a *orld *ar II s8bmarine in te on)a ren$ erea&ter, So'iet #en8s entr 'eiles (ere ea'il rein&ored, like modern s8bmarines, and s8ess&8ll landed on te searin) s8r&ae$ *en it beame lear o( deep te atmospere is and o( tik te lo8ds, So'iet desi)ners beame onerned tat te s8r&a e mi)t be pit-blak$ Venera 9 and 10 (ere eK8ipped (it 1
>ames B$ ollak made important ontrib8tions to e'er area o& planetar siene$ e (as m &irst )rad8ate st8dent and a
ollea)8e e'er sine$ e on'erted NSAs mes esear +enter into a (orld leader in planetar resear and te post-dotoral trainin) o& planetar sientists$ is )entleness (as as eCtraordinar as is sienti&i abilities$ e died in 1994 at te ei)t o& is po(ers$
90
&loodli)ts$ e pro'ed 8nneessar$ &e( perent o& te s8nli)t tat &alls on te top o& te lo8ds makes it tro8) to te s8r&ae, and #en8s is abo8t as bri)t as on a lo8d da on Eart$ e resistane to te idea o& a ot s8r&ae on #en8s an, I s8ppose, be attrib8ted to o8r rel8tane to abandon te notion tat te nearest planet is ospitable &or li&e, &or &8t8re eCploration, and peraps e'en, in te lon)er term, &or 8man settlement$ s it t8rns o8t tere are no +arboni&ero8s s(amps no )lobal oil or selter oeans$ Instead, #en8s is a sti&lin), broodin) in&erno$ ere are some deserts, b8t itAs mainl a (orld o& &roen la'a seas$ 28r opes are 8n&8l&illed$ e all o& tis (orld is no( more m8ted tan in te earl das o& spaera&t eCploration, (en almost antin) (as possible and o8r most romanti notions abo8t #en8s mi)t, &or all (e ten kne(, be realied$
MANY SPACECRAFT CONTRIBUTEDto
o8r present 8nderstandin) o& #en8s$ B8t te pioneerin)
mission (as Mariner 23 Mariner 1 &ailed at la8n andGas te sa o& a raeorse (it a broken le)Gad to be destroed$ Mariner 2 (orked bea8ti&8ll and pro'ided te ke earl radio data on te limate o& #en8s$ It made in&rared obser'ations o& te properties o& te lo8ds$ 2n its (a &rom Eart to #en8s, it diso'ered and meas8red te solar (indGte stream o& ar)ed partiles tat &lo(s o8t(ard &rom te S8n, &illin) te ma)netosperes o& an planets in its (a, blo(in) bak te tails o& omets, and establisin) te distant eliopa8se$ Mariner 2 (as te &irst s8ess&8l planetar probe, te sip tat 8sered in te a)e o& planetar eCploration$ ItAs still in orbit aro8nd te S8n, e'er &e( 8ndred das still approain), more or less tan)entiall, te orbit o& #en8s$ Ea time tat appens, #en8s isnAt tere$ B8t i& (e (ait lon) eno8), #en8s (ill one da be nearb and Mariner 2
San"a Maria
(ere still makin) re)8lar r8ns (it a )ostl re( aross te tlanti bet(een +adi and ispaniola$ In te 'a88m o& interplanetar spae, Mariner 2 so8ld be in mint ondition &or man )enerations$ (is on te e'enin) and mornin) star is tis: tat late in te t(ent-&irst ent8r some )reat sip, on its re)8lar )ra'it-assisted transit to te o8ter Solar Sstem, interepts tis anient derelit and ea'es it aboard, so it an be displaed in a m8se8m o& earl spae tenolo)Gon ars, peraps, or E8ropa, or Iapet8s$
91
+
E
1"
E /2N! E.S id(a bet(een era and erasia, &ires broke &ort &rom te sea and ontin8ed &or &o8r das, so tat te (ole sea boiled and blaed, and te &ires ast 8p an island (i (as )rad8all ele'ated as to8) b le'ers $ $ $ &ter te essation o& te er8ption, te odians, at te time o& teir maritime s8prema, (ere &irst to 'ent8re 8pon
9"
te sene and to eret on te island a temple$ —SB2, %EO%AP, =+$ 7 B$+<
All o'er te Eart, o8 an &ind a kind o& mo8ntain (it one strikin) and 8n8s8al &eat8re$ n ild an reo)nie it: e top seems seared or sK8ared o&&: I& o8 limb to te s8mmit or &l o'er it, o8 diso'er tat te mo8ntain as a ole or rater at its peak$ In some mo8ntains o& tis sort, te raters are small? in oters, te are almost as bi) as te mo8ntain itsel&$ 2asionall, te raters are &illed (it (ater$ Sometimes teAre &illed (it a more amain) liK8id: o8 tiptoe 10 te ed)e, and see 'ast, )lo(in) lakes o& ello(-red liK8id and &o8ntains o& &ire$ ese oles in te tops o& mo8ntains are alled alderas, a&ter te (ord aldron, and te mo8ntains on (i te sit are kno(n, o& o8rse, as 'olanosGa&ter #8lan, te oman )od o& &ire$ ere are peraps 600 ati'e 'olanos diso'ered on Eart$ Some, beneat te oeans, are et to be &o8nd$ tpial 'olani mo8ntain looks sa&e eno8)$ Nat8ral 'e)etat ion r8ns 8p its sides$ erraed &ields deorate its &lanks$ amlets and srines nestle at its base$ nd et, (ito8t (arnin), a&ter ent8ries o& lassit8de, te mo8ntain ma eCplode$ Barra)es o& bo8lders, torrents o& as drop o8t o& te sk$ i'ers o& molten rok ome po8rin) do(n its sides$ ll o'er te Eart people ima)ined tat an ati'e 'olano (as an imprisoned )iant or demon str8))lin) to )et o8t$ e er8ptions o& t$ St$ elens and t$ inat8bo are reent reminders, b8t eCamples an be &o8nd tro8)o8t istor$ In 190" a ot, )lo(in) 'olani lo8d s(ept do(n te slopes o& t$ elee and killed 35,000 people in te it o& St$ ierre on te +aribbean island o& artiniK8e$ assi'e m8d&lo(s &rom te er8ption o& te Ne'ado del 8i 'olano in 19;5 killed more tan "5,000 +olombians$ e er8ption o& t$ #es8'i8s in te &irst ent8r b8ried in as te apless inabitants o& ompeii and er8lane8m and killed te intrepid nat8ralist lin te Elder as e made is (a 8p te side o& te 'olano, intent on arri'in) at a better 8nderstandin) o& its (orkin)s$ =lin (as ardl te last: %i&teen 'olanolo)ists a'e been killed in s8ndr 'olani er8ptions bet(een 1979 and 1993$< e editerranean island o& Santorin =also alled era< is in realit te onl part abo'e (ater o& te rim o& a 'olano no( in8ndated b te sea$
1
e
eCplosion o& te Santorin 'olano in 16"3 B$+$ ma, some istorians tink, a'e elped destro 1
e er8ption o& a nearb s8bmarine 'olano and te rapid onstr8tion 2&A ne( island in 197 B$+$ are desribed b Strabo in te epi)rap to tis apter$
93
te )reat inoan i'iliation on te nearb island o& +rete and an)ed te balane o& po(er in earl lassial i'iliation$ is disaster ma be te ori)in o& te tlantis le)end as related b lato, in (i a i'iliation (as destroed in a sin)le da and ni)t o& mis&ort8ne$ It m8st a'e been eas bak ten to tink tat a )od (as an)r$ #olanos a'e nat8rall been re)arded (it &ear and a(e$ *en medie'al +ristians 'ie(ed te er8ption o& t$ ekla in Ieland and sa( 8rnin) &ra)ments o& so&t la'a s8spended o'er te s8mmit, te ima)ined te (ere seein) te so8ls o& te damned a(aitin) entrane to ell$ %ear&8l o(lin)s, (eepin) and )nasin) o& teet, melanol ries and lo8d (ailin)s (ere d8ti&8ll reported$ e )lo(in) red lakes and s8l&8ro8s )ases (itin te ekla aldera (ere to8)t to be a real )limpse into te 8nder(orld and a on&irmation o& &olk belie&s in ell sand, b smmetr, in its partner, ea'en<$ 'olano is, in &at, an apert8re to an 8nder)ro8nd realm m8 'aster tan te tin s8r&ae laer tat 8mans inabit, and &ar more ostile$ e la'a tat er8pts &rom a 'olano is liK8id rok Grok raised to its meltin) point, )enerall aro8nd 1000U+$ e la'a emer)es &rom a ole in te Eart? as it ools and solidi&ies, it )enerates and later remakes te &lanks o& a 'olani mo8ntain$ e most 'olaniall ati'e loales on Eart tend to be alon) rid)es on te oean &loor and island arsGat te H8ntion o& t(o )reat plates o& oeani r8stGeiter separatin) &rom ea oter, or one slippin) 8nder te oter$ 2n te sea&loor tere are lon) ones o& 'olani er8ptions Gaompanied b s(arms o& eartK8akes and pl8mes o& abssal smoke and ot (aterGtat (e a are H8st be)innin) to obser'e (it robot and manned s8bmersible 'eiles$ Er8ptions o& la'a m8st mean tat te EartAs interior is eCtremel ot$ Indeed, seismi e'idene so(s tat, onl a &e( 8ndred kilometers beneat te s8r&ae, nearl te entire bod o& te Eart is at least sli)tl molten$ e interior o& te Eart is ot, in part, bea8se radioati'e elements tere, s8 as 8rani8m, )i'e o&& eat as te dea? and in part bea8se te Eart retains some o& te ori)inal eat released in its &ormation, (en man small (orlds &ell to)eter b teir m8t8al )ra'it to make te Eart, and (en iron dri&ted do(n to &orm o8r planetAs ore$ e molten rok, or ma)ma, rises tro8) &iss8res in te s8rro8ndin) ea'ier solid roks$ *e an ima)ine 'ast s8bterranean a'erns &illed (it )lo(in), red, b8bblin), 'iso8s liK8ids tat soot 8p to(ard te s8r&ae i& a s8itable annel is b ane pro'ided$ e ma)ma, alled la'a as it po8rs o8t o& te s8mmit aldera, does indeed arise &rom te 8nder(orld$ e so8ls o& te damned a'e so &ar el8ded detetion$ 2ne te 'olano is &8ll b8ilt &rom s8essi'e o8tpo8rin)s, and te la'a is no lon)er spe(in) 8p into te aldera, ten it beomes H8st like an oter mo8ntainGslo(l erodin) bea8se o& rain&all and (indblo(n debris and, e'ent8all, te mo'ement o& ontinental plates aross te EartAs s8r&ae$ o( man ears an a mo8ntain eCist be&ore it is (ased to te seaD asked Bob !lan in te ballad Blo(in) in te *ind$ e ans(er depends on (i planet (eAre talkin) abo8t$ %or te Eart, itAs tpiall abo8t ten million ears$ So mo8ntains, 'olani and oter(ise, m8st be b8ilt on te same timesale? oter(ise te Eart (o8ld be e'er(ere smoot as ansas$ 1 #olani eCplosions an p8n 'ast K8antities o& matterGmainl &ine 1
E'en (it its mo8ntains and s8bmarine trenes, o8r planet is astonisin)l smoot$ I& te Eart (ere te sie o& a billiard ball, te
lar)est prot8beranes (o8ld be less tan a tent o& a millimeter in sieGon te tresold o& bein) too small to see or &eel$
94
droplets o& s8l&8ri aidGinto te stratospere$ ere, &or a ear or t(o, te re&let s8nli)t bak to spae and ool te Eart$ is appened reentl (it te ilippine 'olano, t$ inat8bo, and disastro8sl in 1;15-16 a&ter te er8ption o& te Indonesian 'olano t$ ambora, (i res8lted in te &amine-ridden ear (ito8t a s8mmer$ 'olani er8ption in a8po, Ne( @ealand, in te ear 177 ooled te limate o& te editerranean, al& a (orld a(a, and dropped &ine partiles onto te /reenland ie ap$ e eCplosion o& t$ aama in 2re)on =(i le&t te aldera no( alled +rater .ake< in 4;03 B$+$ ad limati onseK8enes tro8)o8t te nortern emispere$ St8dies o& 'olani e&&ets on te limate (ere on te in'esti)ati'e pat tat e'ent8all led to te diso'er o& n8lear (inter$ e pro'ide important tests o& o8r 8se o& omp8ter models to predit &8t8re limate an)e$ #olani partiles inHeted into te 8pper air are also an additional a8se o& tinnin) o& te oone laer$ So a lar)e 'olani eCplosion in some 8n&reK8ented and obs8re part o& te (orld an alter te en'ironment on a )lobal sale$ Bot in teir ori)ins and in teir e&&ets, 'olanos remind 8s o& o( '8lnerable (e are to minor b8rps and sneees in te EartAs internal metabolism, and o( important it is &or 8s to 8nderstand o( tis s8bterranean eat en)ine (orks$
IN THE FINAL STAGESo&
&ormation o& te EartGas (ell as te oon, ars, and #en8sG
impats b small (orlds are to8)t to a'e )enerated )lobal ma)ma oeans$ olten rok &looded te pre-eCistin) topo)rap$ /reat &loods, tidal (a'es kilometers i), o& &lo(in), redot liK8id ma)ma (elled 8p &rom te interior and po8red o'er te s8r&ae o& te planet, b8rin) e'ertin) in teir pat: mo8ntains, annels, raters, peraps e'en te last e'idene o& m8 earlier, more lement times$ e )eolo)ial odometer (as reset$ ll aessible reords o& s8r&ae )eolo) be)in (it te last )lobal ma)ma &lood$ Be&ore te, ool and solidi&, oeans o& la'a ma be 8ndreds or e'en to8sands o& kilometers tik$ In o8r time, billions o& ears later, te s8r&ae o& s8 a (orld ma be K8iet, inati'e, (it no int o& 8rrent '8lanism$ 2r tere ma beGas on EartGa &e( small-sale b8t ati'e reminders o& an epo (en te entire s8r&ae (as &looded (it liK8id rok$ In te earl das o& planetar )eolo), )ro8nd-based telesopi obser'ations (ere all te data (e ad$ &er'ent debate ad been r8nnin) &or al& a ent8r on (eter te raters o& te oon (ere d8e to impats or 'olanos$ &e( lo( mo8nds (it s8mmit alderas (ere &o8ndG almost ertainl l8nar 'olanos$ B8t te bi) ratersGbo(l or pan-saped and sittin) on te &lat )ro8nd and not te tops o& mo8ntainsG(ere a di&&erent stor$ Some )eolo)ists sa( in tem similarities (it ertain i)l eroded 'olanos on Eart$ 2ters did not$ e best o8nterar)8ment (as tat (e kno( tere are asteroids and omets tat &l past te oon? te m8st it it sometimes? and te ollisions m8st make raters$ 2'er te istor o& te oon a lar)e n8mber o& s8 raters so8ld a'e been p8ned o8t$ So i& te raters (e see are not d8e to impats, (ere ten are te impat ratersD *e no( kno( &rom diret laborator eCamination o& l8nar raters tat te are almost entirel o& impat ori)in$ B8t 4 billion ears a)o tis little (orld,
95
nearl dead toda, (as b8bblin) and 8rnin) a(a, dri'en b prime'al '8lanism &rom so8res o& internal eat no( lon) )one$ In No'ember 1971 , NSAs Mariner 9 spaera&t arri'ed at ars to &ind te planet ompletel obs8red b a )lobal d8st storm$ lmost te onl &eat8res to be seen (ere &o8r ir8lar spots risin) o8t o& te reddis m8rk$ B8t tere (as sometin) pe8liar abo8t tem: e ad oles in teir tops$ s te storm leared, (e (ere able to see 8nmistakabl tat (e ad been 'ie(in) &o8r 8)e 'olani mo8ntains penetratin) tro8) te d8st lo8d, ea apped b a )reat s8mmit aldera$ &ter te storm dissipated, te tr8e sale o& tese 'olanos beame lear$ e lar)estG appropriatel named 2lmp8s ons, or t$ 2lmp8s, a&ter te ome o& te /reek )odsGis more tan "5 kilometers =ro8)l 15 miles< i), d(ar&in) not onl te lar)est 'olano on Eart b8t also te lar)est mo8ntain o& an sort, t$ E'erest, (i stands 9 kilometers abo'e te ibetan platea8$ ere are some "0 lar)e 'olanos on ars, b8t none so massi'e as 2lmp8s ons, (i as a 'ol8me abo8t 100 times tat o& te lar)est 'olano on Eart, a8na .oa in a(aii$ B o8ntin) te a8m8lated impat raters =made b small impatin) asteroids, and readil distin)8ised &rom s8mmit alderas< on te &lanks o& te 'olanos, estimates o& teir a)es an be deri'ed$ Some artian 'olanos t8rn o8t to be a &e( billion ears old, alto8) none dates bak to te 'er ori)in o& ars, abo8t 4$5 billion ears a)o$ Some, inl8din) 2lmp8s ons, are omparati'el ne(Gperaps onl a &e( 8ndred million ears old$ It is lear tat enormo8s 'olani eCplosions o8rred earl in artian istor, peraps pro'idin) an atmospere m8 denser tan te one ars olds toda$ *at (o8ld te plae a'e looked like i& (e ad 'isited it tenD Some 'olani &lo(s on ars =&or eCample, in +erber8s< &ormed as reentl as "00 million ears a)o$ It is, I s8ppose, e'en possibleGalto8) tere is no e'idene eiter (aGt at 2lmp8s ons, te lar)est 'olano (e kno( abo8t &or ertain in te Solar Sstem, (ill be ati'e a)ain$ #olanolo)ists, a patient sort, (o8ld do8btless (elome te e'ent$ In 1990-93 te Magellan spaera&t ret8rned s8rprisin) radar data abo8t te land&orms o& #en8s$ +arto)rapers prepared maps o& almost te entire planet, (it &ine detail do(n to abo8t 100 meters, te )oal-line-to-)oal-line distane in an merian &ootball stadi8m$ ore data (ere radioed ome b Magellan tan b all oter planetar missions ombined$ Sine m8 o& te oean &loor remains 8neCplored =eCept peraps &or still-lassi&ied data aK8ired b te $S$ and So'iet na'ies<, (e ma kno( more abo8t te s8r&ae topo)rap o& #en8s tan abo8t an oter planet, Eart inl8ded$ 8 o& te )eolo) o& #en8s is 8nlike antin) seen on Eart or an(ere else$ lanetar )eolo)ists a'e )i'en tese land&orms names, b8t tat doesnAt mean (e &8ll 8nderstand o( teAre &ormed$ Bea8se te s8r&ae temperat8re o& #en8s is almost 470U+ =900U%<, te roks tere are m8 loser to teir meltin) points tan are tose at te s8r&ae o& te Eart$ oks be)in to so&ten and &lo( at m8 sallo(er depts on #en8s tan on Eart$ is is 'er likel te reason tat man )eolo)ial &eat8res on #en8s seem to be plasti and de&ormed$
96
e planet is o'ered b 'olani plains and i)land platea8s$ e )eolo)ial onstr8ts inl8de 'olani ones, probable sield 'olanos, and alderas$ ere are man plaes (ere (e an see tat la'a as er8pted in 'ast &loods$ Some plains &eat8res ran)in) to o'er "00 kilometers in sie are pla&8ll alled tiks and aranoids =(i translates ro8)l as spiderlike tin)s
Magellan is 'er o8n)$ ere are so &e( impat raters tat e'ertin) older tan abo8t 500 97
million ears1 m8st a'e been eradiatedGon a planet almost ertainl 4$5 billion ears old$ ere is onl one pla8sible erosi'e a)ent adeK8ate &or (at (e see: '8lanism$ ll o'er te planet raters, mo8ntains, and oter )eolo)ial &eat8res a'e been in8ndated b seas o& la'a tat one (elled 8p &rom te inside, &lo(ed &ar, and &roe$ &ter eCaminin) so o8n) a s8r&ae o'ered (it on)ealed ma)ma, o8 mi)t (onder i& tere are an ati'e 'olanos le&t$ None as been &o8nd &or ertain, b8t tere are a &e(G&or eCample, one alled aat onsGtat appear to be s8rro8nded b &res la'a and (i ma indeed still be 8rnin) and belin)$ ere is some e'idene tat te ab8ndane o& s8l&8r ompo8nds in te i) atmospere 'aries (it time, as i& 'olanos at te s8r&a e (ere episodiall inHetin) tese materials into te atmospere$ *en te 'olanos are K8iesent, te s8l&8r ompo8nds simpl &all o8t o& te air$ ereAs also disp8ted e'idene o& li)tnin) plain) aro8nd te mo8ntaintops o& #en8s, as sometimes appens on ati'e 'olanos on Eart$ B8t (e do not kno( &or ertain (eter tere is on)oin) '8lanism on #en8s$ atAs a matter &or &8t8re missions$ Some sientists belie'e tat 8ntil abo8t 500 million ears a)o te #en8s s8r&ae (as almost entirel de'oid o& land&orms$ Streams and oeans o& molten rok (ere relentlessl po8rin) o8t o& te inter ior, &illin) in and o'er in) o'er an relie & tat ad mana) ed to &orm$ ad o8 pl8mmeted do(n tro8) te lo8ds in tat lon)-a)o time, te s8r&ae (o8ld a'e been nearl 8ni&orm and &eat8reless$ t ni)t te landsape (o8ld a'e been ellisl )lo(in) &rom te red eat o& molten la'a$ In tis 'ie(, te )reat internal eat en)ine o& #en8s, (i s8pplied opio8s amo8nts o& ma)ma to te s8r&ae 8ntil abo8t 500 million ears a)o, as no( t8rned o&&$ e planetar eat en)ine as &inall r8n do(n$ In anoter pro'oati'e teoretial model, tis one b te )eopsiist !onald 8rotte, #en8s as plate tetonis like te EartAs b8t it t8rns o&& and on$ i)t no(, e proposes, te plate tetonis are o&&? ontinents do not mo'e alon) te s8r&ae, do not ras into one anoter, do not tereb raise mo8ntain ran)es, and are not later s8bd8ted into te deep interior$ &ter 8ndreds o& millions o& ears o& K8iesene, to8), plate tetonis al(as breaks o8t and s8r&ae &eat8res are &looded b la'a, destroed b mo8ntain b8ildin), s8bd8ted, and oter(ise obliterated$ e last s8 breako8t ended abo8t 500 million ears a)o, 8rotte s8))ests, and e'ertin) as been K8iet sine$ o(e'er, te presene o& oronae ma si)ni&Gon timesales tat are )eolo)iall in te near &8t8reGtat massi'e an)es on te s8r&ae o& #en8s are abo8t to break o8t a)ain$
1
e a)e o& te #en8s s8r&ae, as determined b Magellan radar ima)er, p8ts an additional nail in te o&&in o& te tesis o& Imman8el #eliko'skG(o aro8nd 1950 proposed, to s8rprisin) media alaim, tat 3,500 ears a)o >8piter spat o8t a )iant omet (i made se'eral )rain) ollisions (it te Eart, a8sin) 'ario8s e'ents roniled in te anient books o& man peoples =s8 as te S8n standin) still on >os8aAs ommand<, and ten trans&ormed itsel& into te planet #en8s$ ere ire still people NW o take tese notions serio8sl$
9;
EVEN MORE UNEXPECTEDtan
te )reat artian 'olanos or te ma)ma-&looded s8r&ae o&
#en8s is (at a(aited 8s (en te Vo$ager 1 spaera&t eno8ntered lo, te innermost o& te &o8r lar)e /alilean moons o& >8piter, in ar 1979$ ere (e &o8nd a stran)e, small, m8lti8ed (orld positi'el a(as in 'olanos$ s (e (ated in astonisment, ei)t ati'e pl8mes po8red )as and &ine partiles 8p into te sk$ e lar)est, no( alled eleGa&ter te a(aiian 'olano )oddessGproHeted a &o8ntain o& material "50 kilometers into spae, i)er abo'e te s8r&ae o& Io tan some astrona8ts a'e 'ent8red abo'e te Eart$ B te time Vo$ager 2 arri'ed at Io, &o8r monts later, ele ad t8rned itsel& o&&, alto8) siC o& te oter pl8mes (ere still ati'e, at least one ne( pl8me ad been diso'ered, and anoter aldera, named S8rt, ad an)ed its olor dramatiall$ e olors o& Io, e'en to8) eCa))erated in NSAs olor-enaned ima)es, are like none else(ere in te Solar Sstem$ e 8rrentl &a'ored eCplanation is tat te Ionian 'olanos are dri'en not b 8p(ellin) molten rok, as on te Eart, te oon, #en8s, and ars, b8t b 8p(ellin) s8l&8r dioCide and molten s8l&8r$ e s8r&ae is o'ered (it 'olani mo8ntains, 'olani alderas, 'ents, and lakes o& molten s8l&8r$ #ario8s &orms and ompo8nds o& s8l&8r a'e been deteted on te s8r&ae o& Io and in nearb spaeGte 'olanos blo( some o& te s8l&8r o&& Io alto)eter$1 ese &indin)s a'e s8))ested to some an 8nder)ro8nd sea o& liK8id s8l&8r tat iss8es to te s8r&ae at points o& (eakness, )enerates a sallo( 'olani mo8nd, trikles do(nill, and &reees, its &inal olor determined b its temperat8re on er8ption$ 2n te oon or ars, o8 an &ind man plaes tat a'e an)ed little in a billion ears$ 2n Io, in a ent8r, m8 o& te s8r&ae so8ld be re&looded, &illed in or (ased a(a b ne( 'olani &lo(s$ aps o& Io (ill ten K8ikl beome obsolete, and arto)rap o& Io (ill a'e beome a )ro(t ind8str$ ll tis seems to &ollo( readil eno8) &rom te Vo$ager obser'ations$ e rate at (i te s8r&ae is o'ered o'er b 8rrent 'olani &lo(s implies massi'e an)es in 50 or 100 ears, a predition tat l8kil an be tested$ e Vo$ager ima)es o& to an be ompared (it m8 poorer ima)es taken b )ro8nd-based telesopes 50 ears earlier, and b te 8bble Spae elesope 13 ears later$ e s8rprisin) onl8sion seems to be tat te bi) s8r&ae markin)s on Io a'e ardl an)ed at all$ +learl, (eAre missin) sometin)$
A VOLCANOin
one sense represents te insides o& a planet )8sin) o8t, a (o8nd tat e'ent8all
eals itsel& b oolin), onl to be replaed b ne( sti)mata$ !i&&erent (orlds a'e di&&erent insides$ e diso'er o& liK8id-s8l&8r '8lanism on Io (as a little like &indin) tat an old aK8aintane, (en 8t, bleeds )reen$ o8 ad no idea s8 di&&erenes (ere possible$ e seemed so ordinar$ *e are nat8rall ea)er to &ind additional si)ns o& '8lanism on oter (orlds$ 2n E8ropa, te 1
IoAs 'olanos are also te opio8s so8re o& eletriall ar)ed atoms s8 as oC)en and s8l&8r tat pop8late a )ostl, do8)n8tsaped t8be o& matter tat s8rro8nds >8piter$
99
seond o& te /alilean moons o& >8piter and IoAs nei)bor, tere are no 'olani mo8ntains at all? b8t molten ieGliK8id (aterGseems to a'e )8sed to te s8r&ae tro8) an enormo8s n8mber o& rissrossin) dark markin)s be&ore &reein)$ nd &8rter o8t, amon) te moons o& Sat8rn, tere are si)ns tat liK8id (ater as )8sed 8p &rom te interior and (iped a(a impat raters$ Still, (e a'e ne'er seen antin) tat mi)t pla8sibl be an ie 'olano in eiter te >8piter or Sat8rn sstems$ 2n riton, (e ma a'e obser'ed nitro)en or metane '8lanism$ e 'olanos o& oter (orlds pro'ide a stirrin) spetale$ e enane o8r sense o& (onder, o8r Ho in te bea8t and di'ersit o& te +osmos$ B8t tese eCoti 'olanos per&orm anoter ser'ie as (ell: e elp 8s to kno( te 'olanos o& o8r o(n (orldGand peraps (ill elp one da e'en to predit teir er8ptions$ I& (e annot 8nderstand (atAs appenin) in oter ir8mstanes, (ere te psial parameters are di&&erent, o( deep an o8r 8nderstandin) be o& te ir8mstane o& most onern to 8sD )eneral teor o& '8lanism m8st o'er all ases$ *en (e st8mble 8pon 'ast 'olani eminenes on a )eolo)iall K8iet ars? (en (e diso'er te s8r&ae o& #en8s (iped lean onl esterda b &loods o& ma)ma? (en (e &ind a (orld melted not b te eat o& radioati'e dea, as on Eart, b8t b )ra'itational tides eCerted b nearb (orlds? (en (e obser'e s8l&8r rater tan siliate '8lanism? and (en (e be)in to (onder, in te moons o& te o8ter planets, (eter (e mi)t be 'ie(in) (ater, ammonia, nitro)en, or metane '8lanismGten (e are learnin) (at else is possible$
100
C
H
A
P
T
E
R
13
E /I% 2% 2..2 e )ates o& ea'en are open (ide? 2&& I ride $ $ $ G+A @A IBE! 2 +A N<, E NINE S2N/S, S2N/ #, E /E .2! 2% .I#ES =+IN, +$ I! +EN B$+$<
ItAs a s8ltr ni)t in >8l$ o8A'e &allen asleep in te armair$ br8ptl, o8 startle a(ake, disoriented$ e tele'ision set is on, b8t not te so8nd$ o8 strain to 8nderstand (at o8Are seein)$ (o )ostl (ite &i)8res in o'eralls and elmets are so&tl danin) 8nder a pitblak sk$ e make stran)e little skippin) motions, (i propel tem 8p(ard amid barel pereptible lo8ds o& d8st$ B8t sometin) is (ron)$ e take too lon) to ome do(n$ En8mbered as te are, te seem to be &lin) a little$ o8 r8b o8r ees, b8t te dreamlike tablea8 persists$ 2& all te e'ents s8rro8ndin) Apollo 11As landin) on te oon on >8l "0, 1969, m most 'i'id reolletion is its 8nreal K8alit$ Neil rmstron) and B8 ldrin s8&&led alon) te )ra, d8st l8nar s8r&ae, te Eart loomin) lar)e in teir sk, (ile iael +ollins, no( te oonAs o(n moon, orbited abo'e tem in lonel 'i)il$ es, it (as an astonisin) tenolo)ial aie'ement and a tri8mp &or te nited States$ es, te astrona8ts displaed deat-de&in) o8ra)e$ es, as rmstron) said as e &irst ali)ted, tis (as a istori step &or te 8man speies$ B8t i& o8 t8rned o&& te b-pla bet(een ission +ontrol and te Sea o& ranK8ilit, 101
(it its deliberatel m8ndane and ro8tine atter, and stared into tat blak-and-(ite tele'ision monitor, o8 o8ld )limpse tat (e 8mans ad entered te realm o& mt and le)end$ *e kne( te oon &rom o8r earliest das$ It (as tere (en o8r anestors desended &rom te trees into te sa'annas, (en (e learned to (alk 8pri)t, (en (e &irst de'ised stone tools, (en (e domestiated &ire, (en (e in'ented a)ri8lt8re and b8ilt ities and set o8t to s8bd8e te Eart$ %olklore and pop8lar son)s elebrate a msterio8s onnetion bet(een te oon and lo'e$ e (ord mont and te seond da o& te (eek are bot named a&ter te oon$ Its (aCin) and (anin)G&rom resent to &8ll to resent to ne(G(as (idel 8nderstood as a elestial metapor o& deat and rebirt$ It (as onneted (it te o'8lation le o& (omen, (i as nearl te same periodGas te (ord menstr8ation =.atin meni X mont, &rom te (ord to meas8re< reminds 8s$ ose (o sleep in moonli)t )o mad? te onnetion is preser'ed in te En)lis (ord l8nati$ In te old ersian stor, a 'iier reno(ned &or is (isdom is asked (i is more 8se&8l, te S8n or te oon$ e oon, e ans(ers, bea8se te S8n sines in datime (en itAs li)t o8t an(a$ Espeiall (en (e li'ed o8t-o&-doors, it (as a maHorGi& oddl intan)ibleGpresene in o8r li'es$ e oon (as a metapor &or te 8nattainable: o8 pli)t as (ell ask &or te oon, te 8sed to sa$ 2r o8 an no more do tat tan &l to te oon$ %or most o& o8r istor, e'e ad no idea (at it (as$ spiritD )odD tin)D It didnAt look like sometin) bi) &ar a(a, b8t more like sometin) small nearbGsometin) te sie o& a plate, mabe, an)in) in te sk a little abo'e o8r eads$ nient /reek pilosopers debated te proposition tat te oon is eCatl as lar)e as it looks =betrain) a opeless on&8sion bet(een linear and an)8lar sie<$ :alking on te oon (o8ld a'e seemed a sre(ball idea? it made more sense to ima)ine someo( limbin) 8p into te sk on a ladder or on te bak o& a )iant bird, )rabbin) te oon, and brin)in) it do(n to Eart$ Nobod e'er s8eeded, alto8) tere (ere mts aplent abo8t eroes (o ad tried$ Not 8ntil a &e( ent8ries a)o did te idea o& te oon as a plae, a K8arter-million miles a(a, )ain (ide 8rren$ nd in tat brie& &liker o& time, (eA'e )one &rom te earliest steps in 8nderstandin) te oonAs nat8re to (alkin) and Ho-ridin) on its s8r&ae$ *e al8lated o( obHets mo'e in spae? liK8e&ied oC)en &rom te air? in'ented bi) rokets, telemetr, reliable eletronis, inertial )8idane, and m8 else$ en (e sailed o8t into te sk$ I (as l8k eno8) to be in'ol'ed in te Apollo pro)ram, b8t I donAt blame people (o tink te (ole tin) (as &aked in a oll(ood mo'ie st8dio$ In te late oman Empire, pa)an pilosopers ad attaked +ristian dotrine on te asension to ea'en o& te bod o& +rist and on te promised bodil res8rretion o& te deadGbea8se te &ore o& )ra'it p8lls do(n all eartl bodies$ St$ 8)8stine reHoined: I& 8man skill an b some ontri'ane &abriate 'essels tat &loat, o8t o& metals (i sink$ $ $ o( m8 more redible is it tat /od, b some idden mode o& operation, so8ld e'en more ertainl e&&et tat tese eartl masses be emanipated &rom te ains tat bind tem to EartD at uman so8ld one da diso'er s8 a mode o& operation (as beond ima)inin)$ %i&teen 8ndred ears later, (e emanipated o8rsel'es$ e aie'ement eliited an amal)am o& a(e and onern$ Some remembered te stor o& te o(er o& Babel$ Some, ortodoC oslems amon) tem, &elt settin) &oot on te oonAs s8r&ae to be imp8dene and sarile)e$ an )reeted it as a t8rnin) point in istor$ 10"
e oon is no lon)er 8nattainable$ doen 8mans, all merians, a'e made tose odd bo8ndin) motions te alled moon(alks on te r8n, ratered, anient )ra la'aG be)innin) on tat >8l da in 1969$ B8t sine 197", no one &rom an nation as 'ent8red bak$ Indeed, none o& 8s as )one an$<ere sine te )lor das o& Apollo eCept into lo( Eart orbit Glike a toddler (o takes a &e( tentati'e steps o8t(ard and ten, breatless, retreats to te sa&et o& is moterAs skirts$ 2ne 8pon a time, (e soared into te Solar Sstem$ %or a &e( ears$ en (e 8rried bak$ *D *at appenedD *at (as Apollo reall abo8tD e sope and a8dait o& >on ennedAs a "5, 1961 messa)e to a Hoint session o& +on)ress on r)ent National NeedsGte spee tat la8ned te pollo pro)ramGdaled me$ *e (o8ld 8se rokets not et desi)ned and allos not et onei'ed, na'i)ation and dokin) semes not et de'ised, in order to send a man to an 8nkno(n (orldGa (orld not et eCplored, not e'en in a preliminar (a, not e'en b robotsGand (e (o8ld brin) im sa&el bak, and (e (o8ld do it be&ore te deade (as o'er$ is on&ident prono8nement (as made be&ore an merian ad e'en aie'ed Eart orbit$ s a ne(l minted $!$, I at8all to8)t all tis ad sometin) entrall to do (it siene$ B8t te resident did not talk abo8t diso'erin) te ori)in o& te oon, or e'en abo8t brin)in) samples o& it bak &or st8d$ ll e seemed to be interested in (as sendin) someone tere and brin)in) im ome$ It (as a kind o& ge"ure3 ennedAs siene ad'isor, >erome *iesner, later told me e ad made a deal (it te resident: ! enned (o8ld not laim tat pollo (as abo8t siene, ten e$ *iesner, (o8ld s8pport it$ So i not siene, (atD e pollo pro)ram is reall abo8t politis, oters told me$ is so8nded more promisin)$ Nonali)ned nations (o8ld be tempted to dri&t to(ard te So'iet nion i& it (as aead in spae eCploration, i& te nited States so(ed ins8&&iient national 'i)or$ I didnAt &ollo($ ere (as te nited States, aead o& te So'iet nion in 'irt8all e'er area o& tenolo)Gte (orldAs eonomi, militar, and, on oasion, e'en moral leaderGand Indonesia (o8ld )o +omm8nist bea8se 8ri /a)arin beat >on /lenn to Eart orbitD *atAs so speial abo8t spae tenolo)D S8ddenl I 8nderstood$ Sendin) people to orbit te Eart or robots to orbit te S8n reK8ires roketsGbi), reliable, po(er&8l rokets$ ose same rokets an be 8sed &or n8lear (ar$ e same tenolo) tat transports a man to te oon an arr n8lear (areads al&(a aro8nd te (orld$ e same tenolo) tat p8ts an astronomer and a telesope in Eart orbit an also p8t 8p a laser battle station$ E'en bak ten, tere (as &ani&8l talk in militar irles, East and *est, abo8t spae as te ne( i) )ro8nd, abo8t te nation tat ontrolled spae ontrollin) te Eart$ 2& o8rse strate)i rokets (ere alread bein) tested on Eart$ B8t ea'in) a ballisti missile (it a d8mm (aread into a tar)et one in te middle o& te ai&i 2ean doesnAt b8 m8 )lor$ Sendin) people into spae apt8res te attention and Ima)ination o& te (orld$ o8 (o8ldnAt spend te mone to la8n astrona8ts &or tis reason alone, b8t o& all te (as o& demonstratin) roket poten, tis one (orks best$ It (as a rite o& national manood? te sape o& te boosters made tis point readil 8nderstood (ito8t anone at8all a'in) to eCplain it$ e omm8niation seemed to be transmitted &rom 8nonsio8s mind to 8nonsio8s mind (ito8t te i)er mental &a8lties atin) a (i&& o& (at (as )oin) on$
103
ollea)8es todaGstr8))lin) &or e'er spae siene dollarGma a'e &or)otten o( eas it (as to )et mone &or spae in te )lor das o& pollo and H8st be&ore$ 2& man eCamples, onsider tis eCan)e be&ore te !e&ense ppropriations S8bommittee o& te o8se o& epresentati'es in 195;, onl a &e( monts a&ter Spu"nik 1$ ir %ore ssistant Seretar iard E$ orner is testi&in)? is inter lo8tor is ep$ !aniel >$ %lood =!emorat o& ennsl'ania<:
2NE: Q*R is it desirable &rom te militar point o& 'ie( to a'e a man on te moonD
artl, &rom te lassi point o& 'ie(, bea8se it is tere$ artl bea8se (e mi)t be a&raid tat te $S$S$$ mi)t )et one tere &irst and realie ad'anta)es (i (e ad not antiipated eCisted tere $ $ $ %.22!: QIR& (e )a'e o8 all te mone o8 said (as neessar, re)ardless o& o( m8 it (as, an o8 in te ir %ore it te moon (it sometin), antin), be&ore +ristmasD 2NE: I &eel s8re (e an$ ere is al(as a ertain amo8nt o& risk in tis kind o& 8ndertakin), b8t (e &eel tat (e an do tat? es, sir$ %.22!: a'e o8 asked anbod in te ir %ore or te !epartment o& !e&ense to )i'e o8 eno8) mone, ard(are, and people, startin) at midni)t toni)t, to ip a$ piee o8t o& tat ball o& )reen eese &or a +ristmas present to nle SamD a'e o8 asked &or tatD 2NE: *e a'e s8bmitted s8 a pro)ram to te 2&&ie o& te Seretar o& !e&ense$ It is 8rrentl 8nder onsideration$ %.22!: I am &or )i'in) it to tem as o& tis min8te, r$ +airman, (it o8r s8pplemental, (ito8t (aitin) &or somebod do(nto(n to make 8p is mind to ask &or it$ I& tis man means (at e sas and i& e kno(s (at e is talkin) abo8tGand I tink e doesG ten tis ommittee so8ld not (ait &i'e min8tes more toda$ *e so8ld )i'e im all te mone and all te ard(are and all te people e (ants, re)ardless o& (at anbod else sas or (ants, and tell im to )o 8p on top o& some ill and do it (ito8t an K8estion$
*en resident enned &orm8lated te pollo pro)ram, te !e&ense !epartment ad a sle( o& spae proHets 8nder de'elopmentG(as o& arrin) militar personnel 8p into spae, means o& on'ein) tem aro8nd te Eart, robot (eapons on orbitin) plat&orms intended to soot do(n satellites and ballisti missiles o& oter nations$ Apollo s8pplanted tese pro)rams$ e ne'er reaed operational stat8s$ ase an be made ten tat pollo ser'ed anoter p8rposeGto mo'e te $S$GSo'iet spae ompetition &rom a militar to a i'ilian arena$ ere are some (o belie'e tat enned intended Apollo as a s8bstit8te &or an an8s rae in spae$ abe$ %or me, te most ironi token o& tat moment in istor is te plaK8e si)ned b resident iard $ NiCon tat Apollo 11 took to te oon$ It reads: *e ame in peae &or all 104
mankind$ s te nited States (as droppin) 7M me)atons o& on'entional eCplosi'es on small nations in So8teast sia, (e on)rat8lated o8rsel'es on o8r 8manit: *e (o8ld arm no one on a li&eless rok$ at plaK8e is tere still, attaed to te base o& te pollo 11 .8nar od8le, on te airless desolation o& te Sea o& ranK8ilit$ I& no one dist8rbs it, it (ill still be readable a million ears &rom no($ SiC more missions &ollo(ed Apollo 11, all b8t one o& (i s8ess&8ll landed on te l8nar s8r&ae$ pollo 17 (as te &irst to arr a sientist$ s soon as e )ot tere, te pro)ram (as aneled$ e &irst sientist and te last 8man to land on te oon (ere te same person$ e pro)ram ad alread ser'ed its p8rpose tat >8l ni)t in 1969$ e al&-doen s8bseK8ent missions (ere H8st moment8m$
Apollo (as not mainl abo8t siene$ It (as not e'en mainl abo8t spae$ Apollo (as abo8t ideolo)ial on&rontation and n8lear (arGo&ten desribed b s8 e8pemisms as (orld leadersip and national presti)e$ Ne'erteless, )ood spae siene (as done$ *e no( kno( m8 more abo8t te omposition, a)e, and istor o& te oon and te ori)in o& te l8nar land&orms$ *e a'e made pro)ress in 8nderstandin) (ere te oon ame &rom$ Some o& 8s a'e 8sed l8nar raterin) statistis to better 8nderstand te Eart at te time o& te ori)in o& li&e$ B8t more important tan an o& tis, Apollo pro'ided an ae)is, an 8mbrella 8nder (i brilliantl en)ineered robot spaera&t (ere dispated tro8)o8t te Solar Sstem, makin) tat preliminar reonnaissane o& doens o& (orlds$ e o&&sprin) o& Apollo a'e no( reaed te planetar &rontiers$ I& not &or ApolloGand, tere&ore, i& not &or te politial p8rpose it ser'edGI do8bt (eter te istori merian eCpeditions o& eCploration and diso'er tro8)o8t te Solar Sstem (o8ld a'e o8rred, e Mariner Viking Pioneer Vo$ager and %alileo are amon) te )i&ts o& pollo$ Magellan and #aini are more distant desendants$ Sometin) similar is tr8e &or te pioneerin) So'iet e&&orts in Solar Sstem eCploration, inl8din) te &irst so&t landin)s o& robot spaera&t@&una 9 Mar ' Venera 8-on oter (orlds$ Apollo on'eed a on&idene, ener), and breadt o& 'ision tat did apt8re te ima)ination o& te (orld$ at too (as part o& its p8rpose$ It inspired an optimism abo8t tenolo), an ent8siasm &or te &8t8re$ I& (e o8ld &l to te oon, as so man a'e asked, (at else (ere (e apable o&D E'en tose (o opposed te poliies and ations o& te nited StatesGe'en tose (o to8)t te (orst o& 8sGakno(led)ed te )eni8s and eroism o& te Apollo pro)ram$ *it Apollo, te nited States to8ed )reatness$ *en o8 pak o8r ba)s &or a bi) trip, o8 ne'er kno( (atAs in store &or o8$ e Apollo astrona8ts on teir (a to and &rom te oon poto)raped teir ome planet$ It (as a nat8ral tin) to do, b8t it ad onseK8enes tat &e( &oresa($ %or te &irst time, te inabitants o& Eart o8ld see teir (orld &rom abo'eGte (ole Eart, te Eart in olor, te Eart as an eCK8isite spinnin) (ite and bl8e ball set a)ainst te 'ast darkness o& spae$ ose ima)es elped a(aken o8r sl8mberin) planetar onsio8sness$ e pro'ide inontestable e'idene tat (e all sare te same '8lnerable planet$ e remind 8s o& (at is important and (at is not$ e (ere te arbin)ers o& Vo$ager pale bl8e dot$ *e ma a'e &o8nd tat perspeti'e H8st in time, H8st as o8r tenolo) treatens te abitabilit o& o8r (orld$ *ate'er te reason (e &irst m8stered te Apollo pro)ram, o(e'er mired it (as in +old *ar nationalism and te instr8ments o& deat, te inesapable reo)nition
105
o& te 8nit and &ra)ilit o& te Eart is its lear and l8mino8s di'idend, te 8neCpeted &inal )i&t o& Apollo$ *at be)an in deadl ompetition as elped 8s to see tat )lobal ooperation is te essential preondition &or o& s8r'i'al$ ra'el is broadenin)$ ItAs time to it te road a)ain$
+
E
14
E.2IN/ 2E *2.!S N! 2E+IN/ IS 2NE e planets, in teir 'ario8s sta)es o& de'elopment, are s8bHeted to te same &ormati'e &ores tat operate on o8r eart, and a'e, tere&ore, te same )eolo)i &ormation, and probabl li&e, o& o8r o(n past, and peraps &8t8re? b8t$ &8rter tan tis, tese &ores are atin), in some ases, 8nder totall di&&erent onditions &rom tose 8nder (i te operate on te eart, and ene m8st e'ol'e &orms di&&erent &rom tose e'er kno(n to man$ e 'al8e o& s8 material as tis to te omparati'e sienes is too ob'io8s to need dis8ssion$ G2BE $ /2!!!, N2EB22 =1907<
%or te &irst time in m li&e, I sa( te orion as a 8r'ed line$ It (as aent8ated b a tin seam o& dark bl8e li)t-o8r atmospere$ 2b'io8sl, tis (as not te oean o& air I ad been told it (as so man times in m li&e$ I (as terri&ied b its &ra)ile appearane$ G.% EB2.!, /EN S+E S.E S2N =19;;<
106
Wen o8 look do(n at te Eart &rom orbital altit8des, o8 see a lo'el, &ra)ile (orld embedded in blak 'a88m$ B8t peerin) at a piee o& te Eart tro8) a spaera&t portole is notin) like te Ho o& seein) it entire a)ainst te bakdrop o& blak, orGbetterGs(eepin) aross o8r &ield o& 'ie( as o8 &loat in spae 8nen8mbered b a spaera&t$ e &irst 8man to a'e tis eCperiene (as leCei .eono', (o on ar 1;, 1965, le&t Voko 2 in te ori)inal spae (alk: I looked do(n at te Eart, e realls, and te &irst to8)t tat rossed m mind (as Ve (orld is ro8nd, a&ter all$A In one )lane I o8ld see &rom /ibraltar to te +aspian Sea $ $ $ I &elt like a birdG(it (in)s, and able to &l$ *en o8 'ie( te Eart &rom &arter a(a, as te pollo astrona8ts did, it srinks in apparent sie, 8ntil notin) b8t a little )eo)rap remains$ o8Are str8k b o( sel&-ontained it is$ n oasional dro)en atom lea'es? a pitter-patter o& ometar d8st arri'es$ S8nli) t, )enerated in te immense, silent termon8lear en)ine deep in te solar interior, po8rs o8t o& te S8n in all diretions, and te Eart interepts eno8) o& it to pro'ide a little ill8mination and eno8) eat &or o8r modest p8rposes$ part &rom tat, tis small (orld is on its o(n$ %rom nd te s8r&ae te oon o8o&an it, peraps as ait resent, indistint$ &rom teo&'anta)e point te see o8termost planet is a mere e'en pointits o&ontinents pale li)t$ no( %rom Eart orbit, o8 are str8k b te tender bl8e ar o& te orionGte EartAs tin atmospere seen tan)entiall$ o8 an 8nderstand ( tere is no lon)er s8 a tin) as a loal en'ironmental problem$ ole8les are st8pid$ Ind8strial poisons, )reeno8se )ases, and s8bstanes tat attak te proteti'e oone laer, bea8se o& teir absmal i)norane, do not respet borders$ e are obli'io8s o& te notion o& national so'erei)nt$ nd so, d8e to te almost mti po(ers o& o8r tenolo) =and te pre'alene o& sort-term tinkin)<, (e are be)innin)Gon +ontinental and on planetar salesGto pose a dan)er to o8rsel'es$ lainl, i& tese problems are to be sol'ed, it (ill reK8ire man nations atin) in onert o'er man ears$ IAm str8k a)ain b te iron tat spae&li)tGonei'ed in tile a8ldron o& nationalist ri'alries and atredsGbrin)s (it it a st8nnin) transnational 'ision$ o8 spend e'en a little time ontemplatin) te Eart &rom orbit and te most deepl en)rained nationalisms be)in to erode$ e seem te sK8abbles o& mites on a pl8m$ I& (eAre st8k on one (orld, (eAre limited to a sin)le ase? (e donAt kno( (at else is possible$ enGlike an art &anier &amiliar onl (it %ao8m tomb paintin)s, a dentist (o kno(s onl molars, a pilosoper trained merel in Neolatonism, a lin)8ist (o as st8died onl +inese, or a psiist (ose kno(led)e o& )ra'it is restrited to &allin) bodies on Eart Go8r perspeti'e is &oresortened, o8r insi)ts narro(, o8r prediti'e abilities ir8msribed$ B ontrast, (en (e eCplore oter (orlds, (at one seemed te onl (a a planet o8ld be t8rns o8t to be some(ere in te middle ran)e o& a 'ast spetr8m o& possibilities$ *en (e look at tose oter (orlds, (e be)in to 8nderstand (at appens (en (e a'e too m8 o& one tin) or too little o& anoter$ *e learn o( a planet an )o (ron)$ *e )ain a ne( 8nderstandin), &oreseen b te spae&li)t pioneer obert /oddard, alled omparati'e planetolo)$ e eCploration o& oter (orlds as opened o8r ees in te st8d o& 'olanos, eartK8akes, 107
and (eater$ It ma one da a'e pro&o8nd impliations &or biolo), bea8se all li&e on Eart is b8ilt on a ommon bioemial master plan$ e diso'er o& a sin)le eCtraterrestrial or)anism Ge'en sometin) as 8mble as a bateri8mG(o8ld re'ol8tionie o8r 8nderstandin) o& li'in) tin)s$ B8t te onnetion bet(een eCplorin) oter (orlds and protetin) tis one is most e'ident in te st8d o& EartAs limate and te b8r)eonin) treat to tat limate tat o8r tenolo) poses$ 2ter (orlds pro'ide 'ital insi)ts abo8t (at d8mb tin)s not to do on Eart$ ree potential en'ironmental atastropesGall operatin) on a )lobal saleGa'e reentl been 8no'ered: oone laer depletion, )reeno8se (armin), and n8lear (inter$ ll tree diso'eries, it t8rns o8t, a'e stron) ties to te eCploration o& te planets$ =1< It (as dist8rbin) to &ind tat an inert material (it all sorts o& pratial appliationsGit ser'es as te (orkin) &l8id in re&ri)erators and air onditioners, as aerosol propellant &or deodorants and oter prod8ts, as li)t(ei)t &oam paka)in) &or &ast &oods, and as a leanin) a)ent in miroeletronis, to name onl a &e(-an pose a dan)er to li&e on Eart$ *o (o8ld a'e &i)8redD e mole8les in K8estion are alled loro&l8oroarbons =+%+s<$ +emiall, teAre eCtremel inert, (i means teAre in'8lnerableG8ntil te &ind temsel'es 8p in te oone laer, (ere teAre broken apart b 8ltra'iolet li)t &rom te S8n$ e lorine atoms t8s liberated attak and break do(n te proteti'e oone, lettin) more 8ltra'iolet li)t rea te )ro8nd$ is inreased 8ltra'iolet intensit 8sers in a )astl proession o& potential onseK8enes in'ol'in) not H8st skin aner and atarats, b8t (eakenin) o& te 8man imm8ne sstem and, most dan)ero8s o& all, possible arm to a)ri8lt8re and to potosnteti or)anisms at te base o& te &ood ain on (i most li&e on Eart depends$ *o dis o'ered tat +%+s posed a treat to te oone lae rD *as it te prinipal man8&at8rer, te !8ont +orporation, eCerisin) orporate responsibilitD *as it te En'ironmental rotetion )en protetin) 8sD *as it te !epartment o& !e&ense de&endin) 8sD No, it (as t(o I'or-to(er, (ite-oated 8ni'ersit sientists (orkin) on sometin) elseG Ser(ood o(land and ario olina o& te ni'ersit o& +ali&ornia, Ir'ine$ Not e'en an I' .ea)8e 8ni'ersit$ No one instr8ted tem to look &or dan)ers to te en'ironment$ e (ere p8rs8in) &8ndamental resear$ e (ere sientists &ollo(in) teir o(n interests$ eir names so8ld be kno(n to e'er soolild$ In teir ori)inal al8lations, o(land and olina 8sed rate onstants o& emial reations in'ol'in) lorine and oter alo)ens tat ad been meas8red in part (it NS s8pport$ * NSD Bea8se #en8s as lorine and &l8orine mole8les in its atmospere, and planetar aeronomers ad (anted to 8nderstand (atAs appenin) tere$ +on&irmin) teoretial (ork on te role o& +%+s in oone depletion (as soon done b a )ro8p led b iael Elro at ar'ard o( is it te ad all tese branin) net(orks o& alo)en emial kinetis in teir omp8ter read to )oD Bea8se te (ere (orkin) on te lorine and &l8orine emistr o& te atmospere o& #en8s$ #en8s elped make and elped on&irm te diso'er tat te EartAs oone laer is in dan)er$ n entirel 8neCpeted onnetion (as &o8nd bet(een te atmosperi potoemistries o& te t(o planets$ res8lt o& importane to e'erone on Eart emer)ed &rom (at mi)t (ell a'e seemed te most bl8e-sk,
10;
abstrat, impratial kind o& (ork, 8nderstandin) te emistr o& minor onstit8ents in te 8pper atmospere o& anoter (orld$ ereAs also a ars onnetion$ *it Viking (e &o8nd te s8r&ae o& ars to be apparentl li&eless and remarkabl de&iient e'en in simple or)ani mole8les$ B8t simple or)ani mole8les o8)t to be tere, bea8se o& te impat o& or)ani-ri meteorites &rom te nearb asteroid belt$ is de&i ien is (idel attri b8ted to te lak o& oone on ars$ e Viking mirobiolo) eCperiments &o8nd tat or)ani matter arried &rom Eart to ars and sprinkled on artian s8r&ae d8st is K8ikl oCidied arid destroed$ e materials in te d8st tat do te destr8tion are mole8les sometin) like dro)en peroCideG(i (e 8se as an antisepti bea8se it kills mirobes b oCidiin) tere, ltra'iolet li)t &rom te S8n strikes te s8r&ae o& ars 8nimpeded b an oone laer? i& an or)ani matt er (ere tere, it (o8ld be K8ikl destroed b te 8ltra'iolet li)t itsel& and its oCidation prod8ts$ 8s part o& te reason te topmost laers o& artian soil are antisepti is tat ars as an oone ole o& planetar dimensionsGb itsel& a 8se&8l a8tionar tale &or 8s, (o are b8sil tinnin) and p8nt8rin) o8r oone laer$ ="< /lobal (armin) is predited to &ollo( &rom te inreasin) )reeno8se e&&et a8sed lar)el b arbon dioCide )enerated in te b8rnin) o& &ossil &8elsGb8t also &rom te b8ild8p o& oter in&rared-absorbin) )ases =oCides o& nitro)en, metane, tose same +%+s, and oter mole8les<$ S8ppose tat (e a'e a tree-dimensional )eneral ir8lat ion omp8ter model o& te EartAs limate$ Its pro)rammers laim itAs able to predit (at te Eart (ill be like i& tereAs more o& one atmosperi onstit8ent or less o& anoter$ e model does 'er (ell at preditin) te present limate$ B8t tere is a na))in) (orr: e model as been t8ned so it (ill ome o8t ri)tGtat is, ertain adH8stable parameters are osen, not &rom &irst priniples o& psis, b8t to )et te ri)t ans(er$ is is not eCatl eatin), b8t i& (e appl te same omp8ter model to rater di&&erent limati re)imesGdeep )lobal (armin), &or instaneGte t8nin) mi)t ten be inappropriate$ e model mi)t be 'alid &or todaAs limate, b8t not eCtrapolatable to oters$ 2ne (a to test tis pro)ram is to appl it to te 'er di&&erent limates o& oter planets$ +an it predit te str8t8re o& te atmospere on ars and te limate tereD e (eaterD *at abo8t #en8sD I& it (ere to &ail tese test ases, (e (o8ld be ri)t in mistr8stin) it (en it makes preditions &or o8r o(n planet$ In &at, limate models no( in 8se do 'er (ell in preditin) &rom &irst priniples o& psis te limates on #en8s and ars$ 2n Eart, 8)e 8p(ellin)s o& molten la'a are kno(n and attrib8ted to s8perpl8mes on'etin) 8p &rom te deep mantle and )eneratin) 'ast platea8s o& &roen basalt$ speta8lar eCample o8rred abo8t a 8ndred million ears a)o, and added peraps ten times te present arbon dioCide ontent to te atmospere, ind8in) s8bstantial )lobal (armin)$ ese pl8mes, it is to8)t, o8r episodiall tro8)o8t EartAs istor$ Similar mantle 8p(ellin) seem to a'e o8rred on ars and #en8s$ ere are so8nd pratial reaso ns &or 8s to (ant to 8nderstand o( a maHor an)e to te EartAs s8r&ae and limate o8ld s8ddenl arri'e 8nanno8ned &rom 8ndreds o& kilometers beneat o8r &eet$ Some o& te most important reent (ork on )lobal (armin) as been done b >ames ansen and is ollea)8es at te /oddard Instit8te &or Spae Sienes, a NS &ailit in Ne(
109
ork +it$ ansen de'eloped one o& te maHor omp8ter limate models and emploed it to predit (at (ill appen to o8r limate as te )reeno8se )ases ontin8e to b8ild 8p$ e as been in te &ore&ront o& testin) tese models a)ainst anient limates o& te Eart$ =!8rin) te last ie a)es, it is o& interest to note, more arbon dioCide and metane are strikin)l orrelated (it i)er temperat8res$< ansen olleted a (ide ran)e o& (eater data &rom tis ent8r and last, to see (at at8all appened to te )lobal temperat8re, and ten ompared it to te omp8ter modelAs preditions o& (at oul a'e appened$ e t(o a)ree to (itin te errors o& meas8rement and al8lation, respeti'el$ e o8ra)eo8sl testi&ied be&ore +on)ress in te &ae o& a politiall )enerated order &rom te *ite o8se 2&&ie o& ana)ement and B8d)et =tis (as in te ea)an ears< to eCa))erate te 8nertainties and minimie te dan)ers$ is al8lation on te eCplosion o& te ilippine 'olano t$ inat8bo and is predition o& te res8ltin) temporar deline in te EartAs temperat8re =abo8t al& a de)ree +elsi8s< (ere ri)t on te mone$ e as been a &ore in on'inin) )o'ernments (orld(ide tat )lobal (armin) is sometin) to be taken serio8sl$ o( did ansen )et interested in te )reeno8se e&&et in te &irst plaeD is dotoral tesis =at te ni'ersit o& Io(a in 1967< (as abo8t #en8s$ e a)reed tat te i) radio bri)tness o& #en8s is d8e to a 'er ot s8r&ae, a)reed tat )reeno8se )ases keep te eat in, b8t proposed tat eat &rom te interior rater tan s8nli)t (as te prinipal ener) so8re$ e Pioneer 12 mission to #en8s in 197; dropped entr probes into te atmospere? te so(ed diretl tat te ordinar )reeno8se e&&etGte s8r&ae eated b te S8n and te eat retained b te blanket o& airG(as te operati'e a8se$ B8t itAs #en8s tat )ot ansen tinkin) abo8t te )reeno8se e&&et$ adio astronomers, o8 note, &ind #en8s to be an intense so8re o& radio (a'es$ 2ter eCplanations o& te radio emission &ail$ o8 onl8de tat te s8r&ae m8st be ridi8lo8sl ot$ o8 tr to 8nderstand (ere te i) temperat8res ome &rom and are led ineCorabl to one or anoter kind o& )reeno8se e&&et$ !eades later o8 &ind tat tis trainin) as prepared o8 to 8nderstand and elp predit an 8neCpeted treat to o8r )lobal i'iliation$ I kno( man oter instanes (ere sientists (o &irst tried to p8le o8t te atmosperes o& oter (orlds are makin) important and i)l pratial diso'eries abo8t tis one$ e oter planets are a s8perb trainin) )ro8nd &or st8dents o& te Eart$ e reK8ire bot breadt and dept o& kno(led)e, and te allen)e te ima)ination$ ose (o are skeptial abo8t arbon dioCide )reeno8se (armin) mi)t pro&itabl note te massi'e )reeno8se e&&et on #en8s$ No one proposes tat #en8sAs )reeno8se e&&et deri'es &rot impr8dent #en8sians (o b8rned too m8 oal, dro'e &8el-ine&&iient a8tos, and 8t do(n teir &orests$ point is di&&erent$ e limatolo)ial istor o& o8r planetar nei)bor, an oter(ise Eartlike planet on (i te s8r&ae beame ot eno8) to melt tin or lead, is (ort onsiderin)Gespeiall b tose (o sa tat te inreasin) )reeno8se e&&et on Eart (ill be sel&-orretin), tat (e donAt reall a'e to (orr abo8t it, or =o8 an see tis in te p8bliations o& some )ro8ps tat all temsel'es onser'ati'e< tat te )reeno8se e&&et itsel& is a oaC$ =3< N8lear (inter is te predited darkenin) and oolin) o& te EartGmainl &rom &ine smoke partiles inHeted into te atmospere &rom te b8rnin) o& ities and petrole8m &ailities Gtat is predited to &ollo( a )lobal termon8lear (ar$ 'i)oro8s sienti&i debate ens8ed on
110
H8st o( serio8s n8lear (inter mi)t be$ e 'ario8s opinions a'e no( on'er)ed$ ll treedimensional )eneral ir8lation omp8ter models predit tat te )lobal temperat8res res8ltin) &rom a (orld(ide termon8lear (ar (o8ld be older tan tose in te leistoene ie a)es$ e impliations &or o8r planetar i'iliationGespeiall tro8) te ollapse o& a)ri8lt8reG are 'er dire$ It is a onseK8ene o& n8lear (ar tat (as someo( o'erlooked b te i'il and militar a8torities o& te nited States, te So'iet nion, Britain, %rane, and +ina (en te deided to a8m8late (ell o'er 60,000 n8lear (eapons$ lto8) itAs ard to be ertain abo8t s8 tin)s, a ase an be made tat n8lear *inter plaed a onstr8ti'e role =tere (ere oter a8ses, o& o8rse< in on'inin) te n8lear-armed nations, espeiall te So'iet nion, o& te &8tilit o& n8lear (ar$ N8lear (inter (as &irst al8lated and named in 19;";3 b a )ro8p o& &i'e sientists, to (i IAm pro8d to belon)$ is team (as )i'en te aronm S =&or iard $ 8ro, =e'en B$ oon, omas kerman, >ames ollak, and msel&<$ 2& te &i'e S sientists, t(o (ere planetar sientists, and te oter tree ad p8blised man papers in planetar siene, e earliest intimation o& n8lear (inter ame d8rin) tat same Mariner 9 mission to ars, (en tere (as a )lobal d8st storm and (e (ere 8nable to see te s8r&ae o& te planet? te in&rared spetrometer on te spaera&t &o8nd te i) atmospere to be (armer and te s8r&ae older tan te o8)t to a'e been$ >im ollak and I sat do(n and tried to al8late o( tat o8ld ome abo8t$ 2'er te s8bseK8ent t(el'e ears, tis line o& inK8ir led &rom d8st storms on ars to 'olani aerosols on Eart to te possible eCtintion o& te dinosa8rs b impat d8st to n8lear (inter$ o8 ne'er kno( (ere siene (ill take o8$
PLANETARY SCIENCE&osters
a broad interdisiplinar point o& 'ie( tat pro'es enormo8sl elp&8l in diso'erin) and attemptin) to de&8se tese loomin) en'ironmental atastropes$ *en o8 8t o8r teet on oter (orlds, o8 )ain a perspeti'e abo8t te &ra)ilit o& planetar en'ironments and abo8t (at oter, K8ite di&&erent, en'ironments are possible$ ere ma (ell be potential )lobal atastropes still to be 8no'ered$ I& tere are, I bet planetar sientists (ill pla a entral role in 8nderstandin) tem$ 2& all te &ields o& matematis, tenolo), and sien e, te one (it te )reatest international ooperation =as determined b o( o&ten te o-a8tors o& resear papers ail &rom t(o or more o8ntries< is te &ield alled Eart and spae sienes$ St8din) tis (orld and oters, b its 'er nat8re, tends to be non-loal, non-nationalist, non-a8'inist$ #er rarel do people )o into tese &ields ;e7aue te are internationalists$ lmost al(as, te enter &or oter reasons, and ten diso'er tat splendid (ork, (ork tat omplements teir o(n, is bein) done b researers in oter nations? or tat to sol'e a problem, o8 need data or a perspeti'e =aess to te so8tern sk, &or eCample< tat is 8na'ailable in o8r o8ntr$ nd one o8 eCperiene s8 ooperationG8mans &rom di&&erent parts o& te planet (orkin) in a m8t8all intelli)ible sienti&i lan)8a)e as partners on matters o& ommon onernGitAs ard not to ima)ine it appenin) on oter, nonsienti&i matters$ I msel& onsider tis aspet o& Eart and spae sienes as a ealin) and 8ni&in) &ore in (orld politis? b8t, bene&iial or not, it is inesapable$ *en I look at te e'idene, it seems to me tat planetar eCploration is o& te most
111
pratial and 8r)ent 8tilit &or 8s ere on Eart$ E'en i& (e (ere not ro8sed b te prospet o& eCplorin) oter (orlds, e'en i& (e didnAt a'e a nano)ram o& ad'ent8resome spirit in 8s, e'en i& (e (ere onl onerned &or o8rsel'es and in te narro(est sense, planetar eCploration (o8ld still onstit8te a s8perb in'estment$
C
H
A
P
T
E
R
15
E /ES 2% E *2N!E *2.! 2EN e )reat &lood)ates o& te (onder-(orld s(8n) open$
GEN E.#I..E, MO>, .!#D +E 1 =1;51<
11"
Sometime omin) 8p, peraps H8st aro8nd te orner, tere (ill be a nationGmore likel, a onsorti8m o& nationsGtat (ill (ork te neCt maHor step in te 8man 'ent8re into spae$ eraps it (ill be bro8)t abo8t b ir8m'entin) b8rea8raies and makin) e&&iient 8se o& present tenolo)ies$ eraps it (ill reK8ire ne( tenolo)ies, transendin) te )reat bl8nderb8ss emial rokets$ e re(s o& tese sips (ill set &oot on ne( (orlds$ e &irst bab (ill be born some(ere 8p tere$ Earl steps to(ard li'in) o&& te land (ill be made$ *e (ill be on o8r (a$ nd te &8t8re (ill remember$
TANTALI&ING AND MAJESTIC , ars
is te (orld neCt door, te nearest planet on (i an
astrona8t or osmona8t o8ld sa&el land$ lto8) it is sometimes as (arm as a Ne( En)land 2tober, ars is a ill plae, so old tat some o& its tin arbon dioCide atmospere &reees o8t as dr ie at te (inter pole$ It is te nearest planet (ose s8r&ae (e an see (it a small telesope$ In all te Solar Sstem, it is te planet most like Eart$ part &rom &lbs, tere a'e been onl t(o &8ll s8ess&8l missions to ars: Mariner 9 in 1971, and Viking 1 and " in 1976$ e re'ealed a deep ri&t 'alle tat (o8ld stret &rom Ne( ork to San %raniso? immense 'olani mo8ntains, te lar)est o& (i to(ers ;0,000 &eet abo'e te a'era)e altit8de o& te artian s8r&ae, almost tree times te ei)t o& o8nt E'erest? an intriate laered str8t8re in and amon) te polar ies, resemblin) a pile o& disarded poker ips, and probabl a reord o& past limati an)e? bri)t and dark streaks painted do(n on te s8r&ae b (indblo(n d8st, pro'idin) i)-speed (ind maps o& ars o'er te past deades and ent8ries? 'ast )lobe)irdlin) d8st storms? and eni)mati s8r&ae &eat8res$ 8ndreds o& sin8o8s annels and 'alle net(orks datin) bak se'eral billion ears an be &o8nd, mainl in te ratered so8tern i)lands$ e s8))est a pre'io8s epo o& more beni)n and Eartlike onditionsG'er di&&erent &rom (at (e &ind beneat te ten8o8s and &ri)id atmospere o& o8r time$ Some anient annels seem to a'e been ar'ed b rain&all, some b 8nder)ro8nd sappin) and ollapse, and some b )reat &loods tat )8sed 8p o8t o& te )ro8nd$ i'ers (ere po8rin) into and &illin) )reat to8sand-kilometer-diameter impat basins tat toda are dr as d8st$ *ater&alls d(ar&in) an on Eart toda asaded into te lakes o& anient ars$ #ast oeans, 8ndreds o& meters, peraps e'en a kilometer, deep ma a'e )entl lapped sorelines barel disernible toda$ /a" (o8ld a'e been a (orld to eCplore$ *e are &o8r billion ears late$1 2n Eart in H8st te same period, te &irst miroor)anisms arose and e'ol'ed$ .i&e on Eart is intimatel onneted, &or te most basi emial reasons, (it liK8id (ater$ *e 8mans are o8rsel'es mae o& some tree-K8arters (ater$ e same sorts o& or)ani mole8les tat &ell o8t o& 1
lto8) in a &e( plaes, s8 as te slopes o& te ele'ation alled lba atera, tere are m8ltibraned 'alle net(orks tat b omparison are 'er o8n)$ Someo(, e'en in te most reent billion ears, liK8id (ater seems to a'e &lo(ed ere and tere, &rom time to time, tro8) te deserts o& ars$
113
te sk and (ere )enerated in te air and seas o& anient Eart, so8ld also a'e a8m8lated on anient ars$ Is it pla8sible tat li&e K8ikl ame to be in te (aters o& earl Eart, b8t (as someo( restrained and inibited in te (aters o& earl arsD 2r mi)t te artian seas a'e been &illed (it li&eG&loatin), spa(nin), e'ol'in)D *at stran)e beasts one s(8m tereD *ate'er te dramas o& tose distant times, it all started to )o (ron) aro8nd 3$; billion ears a)o$ *e an see tat te erosion o& anient raters dramatiall be)an to slo( abo8t ten$ s te atmospere tinned, as te ri'ers &lo(ed no more, as te oeans be)an to dr, as te temperat8res pl8mmeted, li&e (o8ld a'e retreated to te &e( remainin) on)enial abitats, peraps 8ddlin) at te bottom o& ie-o'ered lakes, 8ntil it too 'anised and te dead bodies and &ossil remains o& eCoti or)anismsGb8ilt, it mi)t be, on priniples 'er di&&erent &rom li&e on EartG(ere deep-&roen, a(aitin) te eCplorers (o mi)t in some distant &8t8re arri'e on ars$
METEORITES ARE FRAGMENTS OF OTHER WORLDSreo'ered
on Eart$ ost ori)inate in
ollisions amon) te n8mero8s asteroids tat orbit te S8n bet(een te orbits o& ars and >8piter$ B8t a &e( are )enerated (en a lar)e meteorite impats a planet or asteroid at i) speed, )o8)es o8t a rater, and propels te eCa'ated s8r&ae material into spae$ 'er small &ration o& te eHeted roks, millions o& ears later, ma interept anoter (orld$ In te (astelands o& ntartia, te ie is ere and tere dotted (it meteorites, preser'ed b te lo( temperat8res and 8ntil reentl 8ndist8rbed b 8mans$ &e( o& tem, alled SN+ =prono8ned snik< meteorites 1 a'e an aspet abo8t tem tat at &irst seemed almost 8nbelie'able: !eep inside teir mineral and )lass str8t8res, loked a(a &rom te ontaminatin) in&l8ene o& te EartAs atmospere, a little )as is trapped$ *en te )as is analed, it t8rns o8t to a'e eCatl te same emial omposition and isotopi ratios as te air on ars$ *e kno( abo8t artian air not H8st &rom spetrosopi in&erene b8t &rom diret meas8rement on te artian s8r&ae b te Viking landers$ o te s8rprise o& nearl e'erone, te SN+ meteorites ome &rom ars$ 2ri)inall, te (ere roks tat ad melted and re&roen$ adioati'e datin) o& all te SN+ meteorites so(s teir parent roks ondensed o8t o& la'a bet(een 1;0 million and 1$3 billion ears a)o$ en te (ere dri'en o&& te planet b ollisions &rom spae$ %rom o( lon) teA'e been eCposed to osmi ras on teir interplanetar Ho8rnes bet(een ars and Eart, (e an tell o( old te areGo( lon) a)o te (ere eHeted &rom ars$ In tis sense, te are bet(een 10 million and 700,000 ears old$ e sample te most reent 0$l perent o& artian istor$ Some o& te minerals te ontain so( lear e'idene o& a'in) one been in (ater, (arm liK8id (ater$ ese dro-termal minerals re'eal tat someo(, probabl all o'er ars, tere (as reent liK8id (ater$ eraps it ame abo8t (en te interior eat melted 8nder)ro8nd ie$ B8t o(e'er it appened, itAs nat8ral to (onder i& li&e is not entirel eCtint, i& someo( itAs 1
Sort &or Ser)ott-Nakla-+assi)n$ o8 an see ( te aronm is 8sed$
114
mana)ed to an) on into o8r time in transient 8nder)ro8nd lakes, or e'en in tin &ilms o& (ater (ettin) s8bs8r&ae )rains$ e )eoemists E'erett /ibson and al arlsson o& NSAs >onson Spae %li)t +enter a'e eCtrated a sin)le drop o& (ater &rom one o& te SN+ meteorites$ e isotopi ratios o& te oC)en and dro)en atoms tat it ontains are literall 8neartl$ I look on tis (ater &rom anoter (orld as an eno8ra)ement &or &8t8re eCplorers and settlers$ Ima)ine (at (e mi)t &ind i& a lar)e n8mber o& samples, inl8din) ne'er melted soil and roks, (ere ret8rned to Eart &rom artian loales seleted &or teir sienti&i interest$ *e are 'er lose to bein) able to aomplis tis (it small ro'in) robot 'eiles$ e transportation o& s8bs8r&ae material &rom (orld to (orld raises a tantaliin) K8estion: %o8r billion ears a)o tere (ere t(o nei)borin) planets, bot (arm, bot (et$ Impats &rom spae, in te &inal sta)es o& te aretion o& tese planets, (ere o8rrin) at a m8 i)er rate tan toda$ Samples &rom ea (orld (ere bein) &l8n) o8t into spae$ *e are s8re tere (as li&e on at least one o& tem in tis period$ *e kno( tat a &ration o& te eHeted debris stas ool tro8)o8t te proesses o& impat, eHetion, and intereption b anoter (orld$ So o8ld some o& te earl or)anisms on Eart a'e been sa&el transplanted to ars &o8r billion ears a)o, initiatin) li&e on tat planetA 2r, e'en more spe8lati'e, o8ld li&e on Eart a'e arisen b s8 a trans&er &rom arsD i)t te t(o planets a'e re)8larl eCan)ed li&e-&orms &or 8ndreds o& millions o& earsD e notion mi)t be testable$ I& (e (ere to diso'er li&e on ars and &o8nd it 'er similar to li&e on EartGand i&, as (ell, e (ere s8re it (asnAt mirobial ontamination tat (e o8rsel'es ad introd8ed in te o8rse o& o8r eCplorationsGte proposition tat li&e (as lon) a)o trans&erred aross interplanetar spae (o8ld a'e to be taken serio8sl$ IT WAS ONCE THOUGHT tat
li&e is ab8ndant on ars$ E'en te do8r and skeptial astronomer
Simon Ne(omb =in is A"ronom$ &or E4er$;o$ (i (ent tro8) man editions in te earl deades o& tis ent8r and (as te astronom teCt o& m ildood< onl8ded, ere appears to be li&e on te planet ars$ &e( ears a)o tis statement (as ommonl re)arded as &antasti$ No( it is ommonl aepted$ Not intelli)ent 8man li&e, e (as K8ik to add, b8t )reen plants$ o(e'er, (e a'e no( been to ars and looked &or plantsGas (ell as animals, mirobes, and intelli)ent bein)s$ E'en i& te oter &orms (ere absent, (e mi)t a'e ima)ined, as in EartAs deserts toda, and as on Eart &or almost all its istor, ab8ndant mirobial li&e$ e li&e detetion eCperiments on #ikin) (ere desi)ned to detet onl a ertain s8bset o& onei'able biolo)ies? te (ere biased to &ind te kind o& li&e abo8t (i (e kno($ It (o8ld a'e been &oolis to send instr8ments tat o8ld not e'en detet li&e on Eart$ e (ere eCK8isitel sensiti'e, able to &ind mirobes in te most 8npromisin), arid deserts and (astelands on Eart$ 2ne eCperiment meas8red te )ases eCan)ed bet(een artian soil and te artian atmospere in te presene o& or)ani matter &rom Eart$ seond bro8)t a (ide 'ariet or)ani &oodst8&&s marked b a radioati'e traer to see i& tere (ere b8)s in te artian soil (o ate te &ood and oCidied it to radioati'e arbon dioCide$ tird eCperiment introd8ed radioati'e arbon dioCide =and arbon monoCide< to te artian soil to see i& an o& it (as
115
taken 8p b artian mirobes$ o te initial astonisment o&, I tink, all te sientists in'ol'ed, ea o& te tree eCperiments )a'e (at at &irst seemed to be positi'e res8lts$ /ases (ere eCan)ed? or)ani matter (as oCidied? arbon dioCide (as inorporated into te soil$ B8t tere are reasons &or a8tion$ ese pro'oati'e res8lts are not )enerall to8)t to be )ood e'idene &or li&e on ars: e p8tati'e metaboli proesses o& artian mirobes o8rred 8nder a 'er (ide ran)e o& onditions inside te Viking landersG(et =(it liK8id (ater bro8)t &rom Eart< and dr, li)t and dark, old =onl a little abo'e &reein)< to ot =almost te normal boilin) point o& (ater<$ an mirobiolo)ists deem it 8nlikel tat artian mirobes (o8ld be so apable 8nder s8 'aried onditions$ noter stron) ind8ement to skeptiism is tat a &o8rt eCperiment, to look &or or)ani emials in te artian soil, )a'e 8ni&orml ne)ati'e res8lts despite its sensiti'it$ *e eCpet li&e on ars, like li&e on Eart, to be or)anied aro8nd arbonbased mole8les$ o &ind no s8 mole8les at all (as da8ntin) &or optimists amon) te eCobiolo)ists$ e apparentl positi'e res8lts o& te li&e detetion eCperiments is no( )enerall attrib8ted to emials tat oCidie te soil, deri'in) 8ltimatel &rom 8ltra'iolet s8nli)t =as dis8ssed in te pre'io8s apter<$ ere is still a and&8l o& Viking sientists (o (onder i& tere mi)t be eCtremel to8) and ompetent or)anisms 'er tinl spread o'er te artian soilGso teir or)ani emistr o8ld not be deteted, b8t teir metaboli proesses o8ld$ S8 sientists do not den tat 8ltra'iolet-)enerated oCidants are present in te artian soil, b8t stress tat no toro8) eCplanation o& te likin) li&e detetion res8lts &rom oCidants alone as been &ortomin)$ entati'e laims a'e been made o& or)ani matter in SN+ meteorites, b8t te seem instead to be ontaminants tat a'e entered te meteorite a&ter its arri'al on o8r (orld$ So &ar, tere are no laims o& artian mirobes in tese roks &rom te sk$ eraps bea8se it seems to pander to p8bli interest, NS and most #ikin) sientists a'e been 'er ar abo8t p8rs8in) te biolo)ial potesis$ E'en no(, m8 more o8ld be done in )oin) o'er te old data, in lookin) (it #ikin)-tpe instr8ments at ntarti and oter soils tat a'e &e( mirobes in tem, in laborator sim8lation o& te role o& oCidants in te artian soil, and in desi)nin) eCperiments to el8idate tese mattersGnot eCl8din) &8rter seares &or li&eG(it &8t8re ars landers$ I& indeed no 8nambi)8o8s si)nat8res o& li&e (ere determined b a 'ariet o& sensiti'e eCperiments at t(o sites 5,000 kilometers apart on a planet marked b )lobal (ind transport o& &ine partiles, tis is at least s8))esti'e tat ars ma be, toda at least, a li&eless planet$ B8t i& ars i li&eless, (e a'e t(o planets, o& 'irt8all idential a)e and earl onditions, e'ol'in) neCt door to one anoter in te same polar sstem: .i&e e'ol'es and proli&erates on one, b8t not te oter$ *D eraps te emial or &ossil remains o& earl artian li&e an still be &o8ndGs8bs8r&ae, sa&el proteted &rom te 8ltra'iolet radiation and its oCidation prod8ts tat toda &r te s8r&ae$ eraps in a rok &ae eCposed b a landslide, or in te banks o& an anient ri'er 'alle or dr lake bed, or in te polar, laminated terrain, ke e'idene &or li&e on anoter planet is (aitin)$
116
!espite its absene on te s8r&ae o& ars, te planetAs t(o moons, obos and !eimos, seem to be ri in ompleC or)ani matter datin) bak to te earl istor o& te Solar Sstem$ e So'iet Po;o 2 spaera&t &o8nd e'idene o& (ater 'apor bein) o8t-)assed &rom obos, as i& it as an i interior eated b radioati'it$ e moons o& ars ma a'e lon) a)o been apt8red &rom some(ere in te o8ter Solar Sstem? onei'abl, te are amon) te nearest a'ailable eCamples o& 8naltered st8&& &rom te earliest das o& te Solar Sstem$ obos and !eimos are 'er small, ea ro8)l 10 kilometers aross? te )ra'it te eCert is nearl ne)li)ible$ So itAs omparati'el eas to rende'o8s (it tem, land on tem, eCamine tem, 8se tem as a base o& operations to st8d ars, and ten )o ome$ ars alls, a storeo8se o& sienti&i in&ormationGimportant in its o(n ri)t b8t also &or te li)t it asts on te en'ironment o& o8r o(n planet$ ere are msteries (aitin) to be resol'ed abo8t te interior o& ars and its mode o& ori)in, te nat8re o& 'olanos on a (orld (ito8t plate tetonis, te s8lptin) o& land&orms on a planet (it sandstorms 8ndreamt o& on Eart, )laiers and polar land&orms, te esape o& planetar atmosperes, and te apt8re o& moonsGto mention a more or less random samplin) o& sienti&i p8les$ I& ars one ad ab8ndant liK8id (ater and a lement limate, (at (ent (ron)D o( did an Eartlike (orld beome so pared, &ri)id, and omparati'el airlessD Is tere sometin) ere (e so8ld kno( abo8t o8r o(n planetD *e 8mans a'e been tis (a be&ore$ e anient eCplorers (o8ld a'e 8nderstood te all o& ars$ B8t mere sienti&i eCploration does not reK8ire a 8man presene$ *e tan al(as send smart robots$ e are &ar eaper, te donAt talk bak, o8 an send tem to m8 more dan)ero8s loales, arid, (it some ane o& mission &ail8re al(as be&ore 8s, no li'es are p8t at risk$
HAVE YOU SEEN ME(te
bak o& te milk arton read $ HMar O;ser'er, 6A C 4$5A C 3A, "500
k)$ .ast eard &rom on ;"193, 6"7,000 km &rom ars$ $ 2$ all ome (as te plainti'e messa)e on a banner 8n) o8tside te Het rop8lsion .aboratorAs ission 2perations %ailit in late 8)8st 1993$ e &ail8re o& te nited StatesA
Mar O;er4er spaera&t H8st be&ore it (as to insert itsel& into orbit aro8nd ars (as a )reat disappointment$ It (as te &irst post-la8n mission &ail8re o& an merian l8nar or planetar spaera&t in "6 ears$ an sientists and en)ineers ad de'oted a deade o& teir pro&essional li'es to $ 2$ It (as te &irst $S$ mission to ars in 17 earsGsine Viking t(o orbiters and t(o landers in 1976$ It (as also te &irst real post-+old *ar spaera&t: 8ssian sientists (ere on se'eral o& te in'esti)ator teams, and Mar O;er4er (as to at as an essential radio rela link &or larders &rom (at (as ten sed8led to be te 8ssian Mar A94 mission, as (ell as &or a darin) ro'er and balloon mission slated &or Mar 963 e sienti&i instr8ments aboard Mar O;er4er (o8ld a'e napped te )eoemistr o& te planet and prepared te (a &or &8t8re missions, )8idin) landin) site deisions$ It mi)t a'e ast a ne( li)t on te massi'e limate an)e tat seems to a'e o8rred in earl artian istor$ It (o8ld a'e poto)raped some o& te s8r&ae o& ars (it detail better tan t(o 117
meters aross$ 2& o8rse, (e do not kno( (at (onders Mar O;er4er (o8ld a'e 8no'ered$ B8t e'er time (e eCamine a (orld (it ne( instr8ments and in 'astl impro'ed detail, a dalin) arra o& diso'eries emer)es H8st as it did (en /alileo t8rned te &irst telesope to(ard te ea'ens and opened te era o& modern astronom$ ordin) to te +ommission o& InK8ir, te a8se o& te &ail8re (as probabl a r8pt8re o& te &8el tank d8rin) press8riation, )ases and liK8ids sp8tterin) o8t, and te (o8nded spaera&t spinnin) (ildl o8t o& ontrol$ eraps it (as a'oidable$ eraps it (as an 8nl8k aident$ B8t to keep tis matter in perspeti'e, letAs onsider te &8ll ran)e o& missions to te oon and te planets attempted b te nited States and te &ormer So'iet nion: In te be)innin), o8r trak reords (ere poor$ Spae 'eiles ble( 8p at la8n, missed teir tar)ets, or &ailed to &8ntion (en te )ot tere$ s time (ent on, (e 8mans )ot ?
Mariner F beame, in 1964, te &irst spaera&t to take lose-8p pit8res o& ars$ 2r onsider te 19*1 Mariner 8CMariner 9 d8al la8n mission to ars$ Mariner 8 *as to map te planet$ Mariner 9 (as to st8d te eni)mati seasonal and se8lar an)es o& s8r&ae markin)s$ e spaera&t (ere oter(ise idential$ Mariner 8 &ell into te oean$ Mariner 9 &le( on to ars arid beame te &irst spaera&t in 8man istor to orbit anoter planet$ It diso'ered te 'olanos, te laminated terrain in te polar aps, te anient ri'er 'alles, and te aeolian nat8re o& te s8r&ae an)es$ It dispro'ed te anals$ It mapped te planet pole to pole and re'ealed all te maHor )eolo)ial &eat8res o& ars kno(n to 8s toda$ It pro'ided te &irst lose-8p 11;
obser'ations o& members o& a (ole lass o& small (orlds =b tar)etin) te artian moons, obos and !eimos<$ I& (e ad la8ned onl Mariner 8 te endea'or (o8ld a'e been an 8nmiti)ated &ail8re$ *it a d8al la8n it beame a brilliant and istori s8ess$ ere (ere also t(o Viking, t(o Vo$ager, t(o Vega, man pairs o& Venera3 * (as onl one ars 2bser'er &lo(nD e standard ans(er is ost$ art o& te reason it (as so ostl, to8), is tat it (as planned to be la8ned b s8ttle, (i is an almost abs8rdl eCpensi'e booster &or planetar missionsGin tis ase too eCpensi'e &or t(o $ 2$ la8nes$ &ter man s8ttle-onneted delas and ost inreases, NS an)ed its mind and deided to la8n Mar
O;er4er on a /i"an booster$ is reK8ired an additional t(o-ear dela and an adapter to mate te spaera&t to te ne( la8n 'eile$ I& NS ad not been so intent on pro'idin) b8siness &or te inreasin)l 8neonomi s8ttle, (e o8ld a'e la8ned a o8ple o& ears earlier and mabe (it t(o spaera&t instead o& one$ B8t (eter in sin)le la8nes or in pairs, te spae-&arin) nations a'e learl deided tat te time is ripe to ret8rn robot eCplorers to ars$ ission desi)ns an)e? ne( nations enter te &ield? old nations &ind te no lon)er a'e te reso8res$ E'en alread &8nded pro)rams annot al(as be relied 8pon$ B8t 8rrent plans do re'eal sometin) o& te intensit o& e&&ort and te dept o& dediation$ s I (rite tis book, tere are tentati'e plans b te nited States, 8ssia, %rane, /erman, >apan, 8stria, %inland, Ital, +anada, te E8ropean Spae )en, and oter entities &or a oordinated roboti eCploration o& ars$ In te se'en ears bet(een 1996 and "003, a &lotilla o& some t(ent-&i'e spaera&tGmost o& tem omparati'el small and eapGare to be sent &rom Eart to ars$ ere (ill be no K8ik &lbs amon) tem? tese are all lon)-d8ration orbiter and lander missions$ e nited States (ill re-&l all o& te sienti&i instr8ments tat (ere lost on ars O;er4er3 e 8ssian spaera&t (ill ontain parti8larl ambitio8s eCperiments in'ol'in) some t(ent nations$ +omm8niations satellites (ill permit eCperimental stations an(ere on ars to rela teir data bak to Eart$ enetrators sreein) do(n &rom orbit (ill p8n into te artian soil, transmittin) data &rom 8nder)ro8nd$ Instr8mented balloons and ro'in) laboratories (ill (ander o'er te sands o& ars$ Some mirorobots (ill (ei) no more tan a &e( po8nds$ .andin) sites are bein) planned and oordinated$ Instr8ments (ill be ross-alibrated$ !ata (ill be &reel eCan)ed$ ere is e'er reason to tink tat in te omin) ears ars and its msteries (ill beome inreasin)l &amiliar to te inabitants o& te planet Eart$ IN THE COMMAND CENTERon
Eart, in a speial room, o8 are elmeted and )lo'ed$ o8 t8rn
o8r ead to te le&t, and te ameras on te ars robot ro'er t8rn to te le&t$ o8 see, in 'er i) de&inition and in olor, (at te ameras see$ o8 take a step &or(ard, and te ro'er (alks &or(ard$ o8 rea o8t o8r arm to pik 8p sometin) sin in te soil, and te robot arm does like(ise$ e sands o& ars trikle tro8) o8r &in)ers$ e onl di&&i8lt (it tis remote realit tenolo) is tat all tis m8st o8r in tedio8s slo( motion: e ro8nd-trip tra'el time o& te 8p-link ommands &rom Eart to ars and te do(n-link data ret8rned &rom ars to Eart mi)t take al& an o8r or more$ B8t tis is sometin) (e an learn to do$ *e an learn to ontain o8r eCplorator impatiene i& tatAs te prie o& eCplorin) ars$ e ro'er an be made 119
smart eno8) to deal (it ro8tine ontin)enies$ ntin) more allen)in), and it makes a dead stop, p8ts itsel& into a sa&e)8ard mode, and radios &or a 'er patient 8man ontroller to take o'er$ +onH8re 8p ro'in), smart robots, ea o& tem a small sienti&i laborator, landin) in te sa&e b8t d8ll plaes and (anderin) to 'ie( lose-8p some o& tat pro&8sion o& artian *onders$ eraps e'er da a robot (o8ld ro'e to its o(n orion? ea mornin) (e (o8ld see lose-8p (at ad esterda been onl a distant eminene$ e len)tenin) pro)ress o& a tra'erse ro8te o'er te artian landsape (o8ld appear oil ne(s pro)rams and in soolrooms$ eople (o8ld spe8late on (at (ill be &o8nd$ Ni)tl ne(sasts &rom anoter planet, (it teir re'elations o& ne( terrains and ne( sienti&i &indin)s (o8ld make e'erone on Eart a part to te ad'ent8re$ en tereAs artian 'irt8al realit: e data sent bak &rom ars, stored in a modern omp8ter, are &ed into o8r elmet and )lo'es and boots$ o8 are (alkin) in an empt room on Eart, b8t to o8 o8 are on ars: pink skies, &ields o& bo8lders, sand d8nes stretin) to te orion (ere an immense 'olano looms? o8 ear te sand r8nin) 8nder o8r boots, o8 t8rn roks o'er, di) a ole, sample te tin air, t8rn a orner, and ome &ae to &ae (it $ $ $ (ate'er ne( diso'eries (e (ill make on arsGall eCat opies o& (atAs on ars, and all eCperiened &rom te sa&et o& a 'irt8al realit salon in o8r ometo(n$ is is not ( (e eCplore ars, b8t learl (e (ill need robot eCplorers to ret8rn te real realit be&ore it an be reon&i)8red into 'irt8al realit$ Espeiall (it ontin8in) in'estment in robotis and maine intelli)ene, sendin) 8mans to ars anAt be H8sti&ied b siene alone$ nd man more people an eCperiene te 'irt8al ars tan o8ld possibl be sent to te real one$ *e an do 'er (ell (it robots$ I& (eAre )oin) to send people, (eAll need a better reason tan siene and eCploration$ In te 19;0s, I to8)t I sa( a oerent H8sti&iation &or 8man missions to ars$ I ima)ined te nited States and te So'iet nion, te t(o +old *ar ri'als tat ad p8t o8r )lobal i'iliation at risk, Hoinin) to)eter in a &ar-seein), i)-tenolo) endea'or tat (o8ld )i'e ope to people e'er(ere$ I pit8red a kind o& pollo pro)ram in re'erse, in (i ooperation, not ompetition, (as te dri'in) &ore, in
(i tire t(o leadin) spae-&arin) nations (o8ld
to)eter la te )ro8nd(ork &or a maHor ad'ane in 8man istorGte e'ent8al settlement o& anoter planet$ e smbolism seemed so apt$ e same tenolo) tat an propel apoalpti (eapons &rom ontinent to ontinent (o8ld enable te &irst 8man 'oa)e to anoter planet$ It (as a oie o& &ittin) mti po(er: to embrae te planet named a&ter, rater te madness asribed to, te )od o& (ar$ *e s8eeded in interestin) So'iet sientists and en)ineers in s8 a Hoint endea'or$ oald Sa)dee', ten diretor o& te Instit8te &or Spae esear o& te So'iet adem o& Sienes in oso(, (as alread deepl en)a)ed in international ooperation on So'iet roboti missions to #en8s, ars, and alleAs +omet, lon) be&ore te idea beame &asionable$ roHeted Hoint 8se o& te So'iet ir spae station and te Sa"urn #-lass la8n 'eile Energi$a made ooperation attrati'e to te So'iet or)aniations tat man8&at8red tese items o& ard(are? te (ere oter(ise a'in) di&&i8lt H8sti&in) teir (ares$ ro8) a seK8ene o& ar)8ments =elpin) to 1"0
brin) te +old *ar to an end bein) ie& amon) tem<, ten-So'iet leader ikail S$ /orbae' (as on'ined$ !8rin) te !eember 19;7 *asin)ton s8mmit, r$ /orbae'Gasked (at (as te most important Hoint ati'it tro8) (i te t(o o8ntries mi)t smbolie te an)e in teir relationsipG8nesitatin)l replied, .etAs )o to ars to)eter$ B8t te ea)an dministration (as not interested$ +ooperatin) (it te So'iets, akno(led)in) tat ertain So'iet tenolo)ies (ere more ad'aned tan teir merian o8nterparts, makin) some merian tenolo) a'ailable to te So'iets, sarin) redit, pro'idin) an alternati'e &or te arms man8&at8rersGtese (ere not to te dministrationAs likin)$ e o&&er (as t8rned do(n$ ars (o8ld a'e to (ait$ In onl a &e( ears, times a'e an)ed$ e +old *ar is o'er$ e So'iet nion is no more$ e bene&it deri'in) &rom te t(o nations (orkin) to)eter as lost some o& its &ore$ 2ter nationsGespeiall >apan and te onstit8ent members o& te E8ropean Spae )enGa'e beome interplanetar tra'elers$ an H8st and 8r)ent demands are le'ied on te disretionar b8d)ets o& te nations$ B8t te Energi$a ea'-li&t booster still a(aits a mission$ e (orkorse Pro"on roket is a'ailable$ e Mir spae stationG(it a re( on board almost ontin8o8slGstill orbits te Eart e'er o8r and a al&$ !espite internal t8rmoil, te 8ssian spae pro)ram ontin8es 'i)oro8sl$ +ooperation bet(een 8ssia and meria in spae is aeleratin)$ 8ssian osmona8t, Ser)ei rikale', in 1994 &le( on te s8ttle .i7o4er$ =&or te 8s8al one-(eek s8ttle mission d8ration? rikale' ad alread lo))ed 464 das aboard te Mir spae station<$ $S$ astrona8ts (ill 'isit Mir3 merian instr8mentsGinl8din) one to eCamine te oCidants to8)t to destro or)ani mole8les in te artian soilGare to be arried b 8ssian spae 'eiles to ars$ Mar O;er4er (as desi)ned to ser'e as a rela station &or landers in 8ssian ars missions$ e 8ssians a'e o&&ered to inl8de a $S$ orbiter in a &ortomin) Pro"onla8ned m8ltipaload mission to ars$ e merian and 8ssian apabilities in spae siene and tenolo) mes? te interdi)itate$ Ea is stron) (ere te oter is (eak$ is is a marria)e made in ea'en-b8t one tat as been s8rprisin)l di&&i8lt to ons8mmate$ 2n September ", 1993, an a)reement to ooperate in dept (as si)ned in *asin)ton b #ie resident l /ore and rime inister #iktor +ernomrdin$ e +linton dministration as ordered NS to redesi)n te $S$ spae station =alled reeom in te ea)an ears< so it is in te sam e orbit as Mir and an be mated to it: >apanese and E8ropean mod8les (ill be attaed, as (ill a +anadian robot arm$ e desi)ns a'e no( e'ol'ed into (at is alled Spae Station Alpa in'ol'in) almost all te spae&arin) nations$ =+ina is te most notable eCeption$< In ret8rn &or $S$ spae ooperation and an in&8sion o& ard 8rren, 8ssia in e&&et a)reed to alt its sale o& ballisti missile omponents to oter nations, and )enerall to eCerise ti)t ontrols on its eCport o& strate)i (eapons tenolo)$ In tis *a, spae beomes one a)ain, as it (as at te ei)t o& te +old *ar, an instr8ment o& national strate)i poli$ is ne( trend as, to8), made some o& te merian aerospae ind8str and some ke members o& +on)ress pro&o8ndl 8neas$ *ito8t international ompetition, an (e moti'ate 1"1
s8 ambitio8s e&&ortsD !oes e'er 8ssian la8n 'eile 8sed ooperati'el mean less s8pport &or te merian aerospae ind8strD +an merians rel on stable s8pport and ontin8it o& e&&ort in Hoint proHets (it te 8ssiansD =e 8ssians, o& o8rse, ask similar K8estions abo8t te merians$< B8t ooperati'e pro)rams in te lon) term sa'e mone, dra( 8pon te eCtraordinar sienti&i and en)ineerin) talent distrib8ted o'er o8r planet, and pro'ide inspiration abo8t te )lobal &8t8re$ ere ma be &l8t8ations in national ommitments$ *e are likel to take bak(ard as (ell as &or(ard steps$ B8t te o'erall trend seems lear$ !espite )ro(in) pains, te spae pro)rams o& te t(o &ormer ad'ersaries are be)innin) to Hoin$ It is no( possible to &oresee a (orld spae stationGnot o& an one nation b8t o& te planet EartGbein) assembled at 51U inlination to te eK8ator and a &e( 8ndred miles 8p$ dramati Hoint mission, alled %ire and Ie, is bein) dis8ssed in (i a &ast &lb (o8ld be sent to l8to, te last 8neCplored planet? b8t to )et tere, a )ra'it assist &rom te S8n (o8ld be emploed, in te o8rse o& *i small probes (o8ld at8all enter te S8nAs atmospere$ nd (e seem to be on te tresold o& a *orld +onsorti8m &or te sienti&i eCploration o& ars$ It 'er m8 looks as to8) s8 proHets (ill be done ooperati'el or not at all$
WHETHER THERE ARE VALID, ost-e&&eti'e,
broadl s8pportable reasons &or people to 'ent8re
to ars is an open K8estion$ +ertainl tere is no onsens8s$ e matter is treated in te neCt apter$ I (o8ld ar)8e tat i& (e are not e'ent8all )oin) to send people to (orlds as &ar a(a as ars, (e a'e lost te ie& reason &or a spae stationGa permanentl =or intermittentl< o8pied 8man o8tpost in Eart orbit$ spae station is &ar &rom an optim8m plat&orm &or doin) siene eiter lookin) do(n at te Eart, or lookin) o8t into spae, or &or 8tiliin) miro)ra'it =te 'er presene o& astrona8ts messes tin)s 8p<$ %or militar reonnaissane it is m8 in&erior to roboti spaera&t$ ere are no ompellin) eonomi or man8&at8rin) appliations$ It is eCpensi'e ompared to roboti spaera&t$ nd o& o8rse it r8ns some risk o& losin) 8man li'es$ E'er s8ttle la8n to elp b8ild or s8ppl a spae station as an estimated 1 or " perent ane o& atastropi &ail8re$ re'io8s i'ilian and militar spae ati'ities a'e littered lo( Eart orbit (it &ast-mo'in) debrisGtat sooner or later (ill ollide (it a spae station =alto8), so &ar, Mir as ad no &ail8res &rom tis aard<$ spae station is also 8nneessar &or 8man eCploration o& te oon$ pollo )ot tere 'er (ell (it no spae station at all$ *it
Sa"urn V or Energi$a lass la8ners, it also ma be possible to )et to near-eart asteroids or e'en ars (ito8t a'in) to assemble te interplanetar 'eile on an orbitin) spae station$ spae station o8ld ser'e inspirational and ed8ational p8rposes, and it ertainl an elp to solidi& relations amon) te spae&arin) nationsGparti8larl te nited States and 8ssia$ B8t te onl s8bstanti'e &8ntion o& a spae station, as &ar as I an see, is &or lon)-d8ration spae&li)t$ o( do 8mans bea'e in miro )ra'itD o( an (e o8nter pro)ressi'e an)es in blood emistr and an estimated 6 perent bone loss per ear in ero )ra'itD =%or a tree- or &o8r-ear mission to ars tis adds 8p, i& te tra'elers a'e to )o at ero )$<
1""
ese are ardl K8estions in &8ndamental biolo) s8 as !N or te e'ol8tionar proess? instead te address iss8es o& applied 8man biolo)$ ItAs important to kno( te ans(ers, b8t onl i& (e intend to )o some(ere in spae tatAs &ar a(a and takes a lon) time to )et tere$ e onl tan)ible and oerent )oal o& a spae station is e'ent8al 8man missions to near-Eart asteroids, ars, and beond$ istoriall NS as been a8tio8s abo8t statin) tis &at learl, probabl &or &ear tat members o& +on)ress (ill tro( 8p teir ands in dis)8st, deno8ne te spae station as te tin ed)e o& an eCtremel eCpensi'e (ed)e, and delare te o8ntr 8nread to ommit to la8nin) people to ars$ In e&&et, ten, NS as kept K8iet abo8t (at te spae station is reall &or$ nd et i& (e ad s8 a spae station, notin) (o8ld reK8ire 8s to )o strai)t to ars$ *e o8ld 8se a spae station to a8m8late and re&ine te rele'ant kno(led)e, and take as lon) as (e like to do soGso tat (en te time does ome, (en (e are read to )o to te planets, (e (ill a'e te bak)ro8nd and eCperiene to do so sa&el$ e Mar O;er4er &ail8re, and te atastropi loss o& te spae s8ttle #allenger in 19;6, remind 8s tat tere (ill be a ertain irred8ible ane o& disaster in &8t8re 8man &li)ts to ars and else( ere$ e Apollo 1' mission, (i (as 8nable to land on te oon and barel ret8rned sa&el to Eart, 8ndersores o( l8k (eA'e been$ *e annot make per&etl sa&e a8tos or trains e'en to8) (eA'e been at it &or more tan a ent8r$ 8ndreds o& to8sands o& ears a&ter (e &irst domestiated &ire, e'er it in te (orld as a ser'ie o& &ire&i)ters bidin) teir time 8ntil tereAs a blae tat needs p8ttin) o8t$ In +ol8mb8sA &o8r 'oa)es to te Ne( *orld, e lost sips le&t and ri)t, inl8din) one tird o& te little &leet tat set o8t in 149"$ I& (e are to send people, it m8st be &or a 'er )ood reasonGand (it a realisti 8nderstandin) tat almost ertainl (e (ill lose li'es$ strona8ts and osmona8ts a'e al(as 8nderstood tis$ Ne'erteless, tere as been and (ill be no sorta)e o& 'ol8nteers$ B8t ( arsD * not ret8rn to te oonD ItAs nearb, and (eA'e pro'ed (e kno( o( to send people tere$ IAm onerned tat te oon, lose as it is, is a lon) deto8r, i& not a dead end$ *eA'e been tere$ *eA'e e'en bro8)t some o& it bak$ eople a'e seen te oon roks, and, &or reasons tat I belie'e are &8ndamentall so8nd, te are bored b te oon$ ItAs a stati, airless, (aterless, blak-sk, dead (orld$ Its most interestin) aspet peraps is its ratered s8r&ae, a reord o& anient ,atastropi impats, on te Eart as (ell as on te oon$ ars, b ontrast, as (eater, d8st storms, its o(n moons, 'olanos, polar ie aps, pe8liar land&orms, anient ri'er 'alles, and e'idene o& massi'e limati an)e on a oneEartlike (orld$ It olds some prospet o& past or mabe e'en present li&e, and is te most on)enial planet &or &8t8re li&eG8mans transplanted &rom Eart, li'in) o&& te land$ None o& tis is tr8e &or te oon$ ars also as its o(n le)ible raterin) istor$ It ars, rater tan te oon, ad been (itin eas rea, (e (o8ld not a'e baked o&& &rom manned spae &li)t$ Nor is te oon an espeiall desirable test bed or (a station &or ars$ e artian and l8nar en'ironments are 'er di&&erent, and te oon is as distant &rom ars as is te Eart$ e mainer &or artian eCploration an at least eK8all (ell be tested in Eart orbit, or on nearEart asteroids, or on te Eart itsel&Gin ntartia, &or instane$
1"3
>apan as tended to be skeptial o& te ommitment o& te nited States and oter nations to plan and eCe8te maHor ooperati'e proHets in spae$ is is at least one reason tat >apan, more tan an oter spae&arin) nation, as tended to )o it alone$ e .8nar and lanetar Soiet o& >apan is an or)aniation representin) spae ent8siasts in te )o'ernment, 8ni'ersities, and maHor ind8stries$ s I (rite, te Soiet is proposin) to onstr8t and stok a l8nar base entirel (it robot labor$ It is said to take abo8t 30 ears and to ost abo8t a billion $S$ dollars a ear =(i (o8ld represent 7 perent o& te present $S$ i'ilian spae b8d)et<$ 8mans (o8ld arri'e onl (en te base is &8ll read$ e 8se o& robot onstr8tion re(s 8nder radio ommand &rom Eart is said to red8e te ost ten&old$ e onl tro8ble (it te seme, aordin) to reports, is tat oter sientists in >apan keep askin), *atAs it &orD atAs a )ood K8estion in e'er nation$ e &irst 8man mission to ars is no( probabl too eCpensi'e &or an one nation to p8ll o&& b itsel&$ Nor is it &ittin) tat s8 a istori step be taken b representati'es o& onl a small &ration o& te 8man speies$ B8t a ooperati'e 'ent8re amon) te nited States, 8ssia, >apan, te E8ropean Spae )enGand peraps oter nations, s8 as +inaGmi)t be &easible in te not too distant &8t8re$ e international spae station (ill a'e tested o8r abilit to (ork to)eter on )reat en)ineerin) proHets in spae$ e ost o& sendin) a kilo)ram o& sometin) no &arter a(a tan lo( Eart orbit is toda abo8t te same as te ost o& kilo)ram o& )old$ is is s8rel a maHor reason (e a'e et to stride te anient sorelines o& ars$ 8ltista)e emial rokets are te means tat &irst took 8s into spae, and tatAs (at (eA'e been 8sin) e'er sine$ *eA'e tried to re&ine tem, to make tere sa&er, more reliable, simpler, eaper$ B8t tat asnAt appened, or at least not nearl as K8ikl as man ad oped$ So mabe tereAs a better (a: mabe sin)le-sta)e rokets tat an la8n teir paloads diretl to orbit? mabe man small paloads sot &rom )8ns or roket-la8ned &rom airplanes? mabe s8personi ramHets$ abe tereAs sometin) m8 better tat (e a'enAt to8)t o& et$ I& (e an man8&at8re propellants &or te ret8rn trip &rom te air and soil o& o8r destination (orld, te di&&i8lt o& te 'oa)e (o8ld be )reatl eased$ 2ne (eAre 8p tere in spae, 'ent8rin) to te planets, roketr is not neessaril te best means to mo'e lar)e paloads aro8nd, e'en (it )ra'it assists$ oda, (e make a &e( earl roket b8rns and later mido8rse orretions, and oast te rest o& te (a$ B8t tere are promisin) ion and n8lear eletri prop8lsion sstems b (i a small and stead aeleration is eCerted$ 2r, as te 8ssian spae pioneer onstantin siolko'sk &irst en'isioned, (e o8ld emplo solar sailsG'ast b8t 'er tin &ilms tat at s8nli)t and te solar (ind, a ara'el kilometers (ide plin) te 'oid bet(een te (orlds$ Espeiall &or trips to ars and beond, s8 metods are &ar better tan rokets$ s (it most tenolo)ies, (en sometin) barel (orks, (en itAs te &irst o& its kind, tereAs a nat8ral tenden to impro'e it, de'elop it, eCploit it$ Soon tereAs s8 an instit8tional in'estment in te ori)inal tenolo), no matter o( &la(ed, tat itAs 'er ard to mo'e on to sometin) better$ NS as almost no reso8res to p8rs8e alternati'e prop8lsion tenolo)ies$ at mone (o8ld a'e to ome o8t o& near-term missions, missions (i o8ld pro'ide 1"4
onrete res8lts and impro'e NSAs s8ess reord$ Spendin) mone on alternati'e tenolo)ies pas o&& a deade or t(o in te &8t8re$ *e tend to be 'er little interested in a deade or t(o in te &8t8re$ is is one o& te (as b (i initial s8ess an so( te seeds o& 8ltimate &ail8re? and is 'er similar to (at sometimes appens in biolo)ial e'ol8tion$ B8t sooner or later some nationGperaps one (ito8t a 8)e in'estment in mar)inall e&&eti'e tenolo)G(ill de'elop e&&eti'e alternati'es$ E'en be&ore ten, i& (e take a ooperati'e pat, tere (ill ome a timeGperaps in te &irst deades o& te ne( ent8r and te ne( millenni8mG(en an interplanetar spaera&t is assembled in Eart orbit, te pro)r ess in &8ll 'ie( on te e'enin) ne(s$ strona8ts and osmona8ts, o'erin) like )nats, )8ide and mate te pre&abriated parts$ E'ent8all te sip, tested and read, is boarded b its international re(, and boosted to esape 'eloit$ %or te (ole o& te 'oa)e to ars and bak, te li'es o& te re( members depend on one anoter, a miroosm o& o8r at8al ir8mstanes do(n ere on Eart$ eraps te &irst Hoint interplanetar mission (it 8man re(s (ill be onl a &lb or orbit o& ars$ Earlier, robot 'eiles, (it aerobrakin), para8tes, and retrorokets, (ill a'e set )entl do(n on te artian s8r&ae to ollet samples and ret8rn tem to Eart, and to emplae s8pplies &or &8t8re eCplorers$ B8t (eter or not (e a'e ompellin), oerent reasons, I am s8reG8nless (e destro o8rsel'es &irstGtat te da (ill ome (en (e 8mans set &oot on ars$ It is onl a matter o& (en$ ordin) to solemn treat, si)ned in *asin)ton and oso( on >an8ar "7, 1967, no nation ma la laim to part or all o& anoter planet$ Ne'ertelessG&or istorial reasons tat +ol8mb8s (o8ld a'e 8nderstood (ellGsome people are onerned abo8t (o &irst sets &oot on ars$ I& tis reall (orries 8s, (e an arran)e &or te ankles o& te re( members to be tied to)eter as te ali)t in te )entle artian )ra'it$ e re(s (o8ld aK8ire ne( and pre'io8sl seK8estered samples, in part to sear &or li&e, in part to 8nderstand te past and &8t8re o& ars and Eart$ e (o8ld eCperiment, &or later eCpeditions, on eCtratin) (ater, oC)en, and dro)en &rom te roks and te air and &rom te 8nder)ro8nd perma&rostGto drink, to breate, to po(er teir maines and, as roket &8el and oCidier, to propel te ret8rn 'oa)e$ e (o8ld test artian materials &or e'ent8al &abriation o& bases and settlements on ars$ nd te (o8ld )o eCplorin)$ *en I ima)ine te earl 8man eCploration o& ars, itAs al(as a ro'in) 'eile, a little like a Heep, (anderin) do(n one o& te 'alle net(orks, te re( (it )eolo)ial ammers, ameras, and analti instr8ments at te read$ eAre lookin) &or roks &rom a)es past, si)ns o& anient atalsms, l8es to limate an)e, stran)e emistries, &ossils, orGmost eCitin) and most 8nlikelGsometin) ali'e$ eir diso'eries are tele'ised bak to Eart at te speed o& li)t$ Sn8))led 8p in bed (it te kids, o8 eCplore te anient ri'erbeds o& ars$
1"5
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SCALING HEAVEN
*o, m &riend, an sale ea'enD
@/E EP!# O %!&%AMES =SE, I! I..ENNI B$+$<
atD, I sometimes ask msel& in amaement: 28r anestors (alked &rom East &ria to W No'aa @emla and ers ok and ata)onia, 8nted elepants (it stone spearpoints, tra'ersed te polar seas in open boats 7,000 ears a)o, ir8mna'i)ated te Eart propelled b notin) b8t (ind, (alked te oon a deade a&ter enterin) spaeGand (eAre da8nted b a 'oa)e to arsD B8t ten I remind msel& o& te a'oidable 8man s8&&erin) on Eart, o( a &e( dollars an sa'e te li&e o& a ild din) o& dedration, o( man ildren (e o8ld sa'e &or te ost o& a trip to arsGand &or te moment I an)e m mind$ Is it 8n(ort to sta ome or 8n(ort to )oD 2r a'e I posed a &alse diotomD IsnAt it possible to make a better li&e &or e'erone on Eart an to rea &or te planets and te starsD *e ad an eCpansi'e r8n in te A60s and A70s$ o8 mi)t a'e to8)t, as I did ten, tat o8r speies (o8ld be on ars be&ore te ent8r (as o'er$ B8t instead, (eA'e p8lled in(ard$
1"6
obots aside, (eA'e baked o&& &rom te planets and te stars$ 1 keep askin) msel& Is it a &ail8re o& ner'e or a si)n o& mat8ritD abe itAs te most (e o8ld reasonabl a'e eCpeted$ In a (a itAs amain) tat it (as possible at all: *e sent a doen 8mans on (eek-lon) eC8rsions to te oon$ nd (e (ere )i'en te reso8res to make a preliminar reonnaissane o& te (ole Solar Sstem, o8t to Nept8ne an(aGmissions tat ret8rned a (ealt o& data, b8t notin) o& sort-term, e'erda, bread-on-te-table pratial 'al8e$ e li&ted te 8man spirit, to8)$ e enli)tened 8s abo8t o8r plae in te ni'erse$ ItAs eas to ima)ine skeins o& istorial a8salit in (i tere (ere no rae to te oon and no planetar pro)ram$ B8t itAs also possible to ima)ine a m8 more serio8s de'otion to eCploration, bea8se o& (i (e (o8ld toda a'e robot 'eiles probin) te atmosperes o& all te >o'ian planets and doens o& moons, omets, and asteroids? a net(ork o& a8tomati sienti&i stations emplaed on ars (o8ld dail be reportin) teir &indin)s? and samples &rom man (orlds (o8ld be 8nder eCamination in te laboratories o& EartGre'ealin) teir )eolo), emistr, and peraps e'en teir biolo)$ 8man o8tposts mi)t be alread establised on te near-Eart asteroids, te oon, and ars$ ere (ere man possible istorial pats$ 28r parti8lar a8salit skein as bro8)t 8s to a modest and r8dimentar, alto8) in man respets eroi, series o& eCplorations$ B8t it is &ar interior to (at mi)t a'e beenGand (at ma one da be$ TO CARRY THE GREEN rometean
spark o& .i&e (it 8s into te sterile 'oid and i)nite tere a
&irestorm o& animate matter is te 'er destin o& o8r rae, reads te bro8re o& sometin) alled te %irst illennial %o8ndation$ It promises, &or Y1"0 a ear, itiensip in spae oloniesG(en te time omes$ Bene&ators (o ontrib8te more also reei'e te 8ndin) )ratit8de o& a star-&l8n) i'iliation, and teir name ar'ed on te monolit to be ereted on te oon$ is represents one eCtreme in te ontin88m o& ent8siasm &or a 8man presene in spae$ e oter eCtremeGbetter represented in +on)ressGK8estions ( (e so8ld be in spae at all, espeiall people rater tan robots$ e pollo pro)ram (as a moondo))le, te soial riti mitai Etioni one alled it? (it te +old *ar o'er, tere is no H8sti&iation (ate'er, proponents o& tis orientation old, &or a manned spae pro)ram$ *ere in tis spetr8m o& poli options so8ld (e beD E'er sine te nited States beat te So'iet nion to te oon, a oerent, (idel 8nderstood H8sti&iation &or 8mans in spae seems to a'e 'anised$ residents and +on)ressional ommittees p8le o'er (at to do (it te manned spae pro)ram$ *at is it &orD * do (e need itD B8t te eCploits o& te astrona8ts and te moon landin)s ad eliitedG and &or )ood reasonGte admiration o& te (orld$ It (o8ld be a reHetion o& tat st8nnin) merian aie'ement, te politial leaders tell temsel'es, to bak o&& &rom manned spae&li)t$ *i resident, (i +on)ress (ises to be responsible &or te end o& te merian spae pro)ramD nd in te &ormer So'iet nion a similar ar)8ment is eard: Sall (e abandon, te ask temsel'es, te one remainin) i) tenolo) in (i (e are still (orld leadersD Sall (e be &aitless eirs o& onstantin siolko'sk, Ser)ei orole', and 8ri
1"7
/a)arinD e &irst la( o& b8rea8ra is to )8arantee its o(n ontin8ane$ .e&t to its o(n de'ies, (ito8t lear instr8tions &rom abo'e, NS )rad8all de'ol'ed into a pro)ram tat (o8ld maintain pro&its, Hobs, and perK8isites$ ork-barrel politis, (it +on)ress plain) a leadin) role, beame an inreasin)l po(er&8l &ore in te desi)n and eCe8tion o& missions and lon)term )oals$ e b8rea8ra ossi&ied$ NS lost its (a$ 2n >8l "0, 19;9, te t(entiet anni'ersar o& te Apollo 11 landin) on te oon, resident /eor)e B8s anno8ned a lon)-term diretion &or te $S$ spae pro)ram$ +alled te Spae ECploration Initiati'e =SEI<, it proposed a seK8ene o& )oals inl8din) a $S$ spae station, a ret8rn o& 8mans to te oon, and te &irst landin) o& 8mans on ars$ In a later statement, r$ B8s set "019 as te tar)et date &or te &irst &oot&all on tat planet$ nd et te Spae ECploration Initiati'e, despite lear diretion &rom te top, &o8ndered$ %o8r ears a&ter it (as mandated, it did not e'en a'e a NS o&&ie dediated to it$ Small and ineCpensi'e l8nar roboti missionsGtat oter(ise mi)t (ell a'e been appro'edG(ere aneled b +on)ress bea8se o& )8ilt b assoiation (it SEI$ *at (ent (ron)D 2ne problem (as te timesale$ SEI eCtended &i'e or so presidential terms o& o&&ie into te &8t8re =takin) te a'era)e presiden as one and a al& terms<$ at makes it eas &or a president to attempt to ommit is s8essors, b8t lea'es in onsiderable do8bt o( reliable s8 a ommitment mi)t be$ SEI ontrasted dramatiall (it te pollo pro)ramG(i, it mi)t a'e been onHet8red at te time it be)an, o8ld a'e tri8mped (en resident enned or is immediate politial eir (as still in o&&ie$ Seond, tere (as onern abo8t (eter NS, (i ad reentl eCperiened )reat di&&i8lt in sa&el li&tin) a &e( astrona8ts "00 miles abo'e te Eart, o8ld send astrona8ts on an arin) ear-lon) traHetor to a destination 100 million miles a(a and brin) tem bak ali'e$ ird, te pro)ram (as onei'ed eCl8si'el in nationalist terms$ +ooperation (it oter nations (as not &8ndamental to eiter desi)n or eCe8tion$ #ie resident !an T8ale, (o ad nominal responsibilit &or spae, H8sti&ied te spae station as a demonstration tat te nited States (as te (orldAs onl s8perpo(er$ B8t sine te So'iet nion ad an operational spae station tat (as a deade aead o& te nited States, r$ T8aleAs ar)8ment pro'ed di&&i8lt to &ollo($ %inall, tere (as te K8estion o& (ere, in terms o& pratial politis, te mone (as s8pposed to ome &rom$ e osts o& )ettin) te &irst 8mans to ars ad been 'ario8sl estimated, ran)in) as i) as Y500 billion$ 2& o8rse, itAs impossible to predit osts be&ore o8 a'e a mission desi)n$ nd te mission desi)n depends on s8 matters as te sie o& te re(? te eCtent to (i o8 take miti)atin) steps a)ainst solar and osmi radiation aards, or ero )ra'it? and (at oter risks o8 are (illin) to aept (it te li'es o& te men and (omen on board$ I& e'er re( member as one essential speialt, (at appens i& one o& tem &alls illD e lar)er te re(, te more reliable te bak8ps$ o8 (o8ld almost ertainl not send a &8ll-time oral s8r)eon, b8t (at appens i& o8 need root anal (ork and o8Are a 8ndred million miles &rom te nearest dentistD 2r o8ld it be done b an endodontist on Eart, 8sin) telepreseneD
1";
*erner 'on Bra8n (as te Nai-merian en)ineer (o, more tan anone else, at8all took 8s into spa e$ is 195" boo k .a Marproek" en'isioned a &irst mission (it 10 interplanetar spaera&t, 70 re( members, and 3 landin) boats$ ed8ndan (as 8ppermost in is mind$ e lo)istial reK8irements, e (rote, are no )reater tan tose &or a minor militar operation eCtendin) o'er a limited teater o& (ar$ e meant to eCplode one and &or all te teor o& te solitar spae roket and its little band o& bold interplanetar ad'ent8rers, and appealed to +ol8mb8sA tree sips (ito8t (i istor tends to pro'e tat e mi)t ne'er a'e ret8rned to Spanis sores$ odern ars mission desi)ns a'e i)nored tis ad'ie$ e are m8 less ambitio8s tan on Bra8nAs, tpiall allin) &or one or t(o spaera&t re(ed b tree to ei)t astrona8ts, (it anoter roboti ar)o sip or t(o$ e solitar roket and te little band o& ad'ent8rers are still (it 8s$ 2ter 8nertainties a&&etin) mission desi)n and ost inl8de (eter o8 pre-emplae s8pplies &rom Eart and la8n 8mans to ars onl a&ter te s8pplies are sa&el landed? (eter o8 an 8se artian materials to )enerate oC)en to breate, (ater to drink, and roket propellants to )et ome? (eter o8 land 8sin) te tin artian atmospere &or aerobrakin)? te de)ree o& red8ndan in eK8ipment to8)t pr8dent? te eCtent to (i o8 8se losed eolo)ial sstems or H8st depend on te &ood, (ater, and (aste disposal &ailities o8A'e bro8)t &rom Eart? te desi)n o& ro'in) 'eiles &or te re( to eCplore te artian landsape? and o( m8 eK8ipment o8Are (illin) to arr to test o8r abilit to li'e o&& te land in later 'oa)es$ ntil s8 K8estions are deid ed, itAs abs8rd to aept an &i)8re &or te ost o& te pro)ram$ 2n te oter and, it (as eK8all lear tat SEI (o8ld be eCtremel eCpensi'e$ %or all tese reasons, te pro)ram (as a nonstarter$ It (as stillborn$ ere (as no e&&eti'e attempt b te B8s dministration to spend politial apital to )et SEI )oin)$ e lesson to me seems lear: ere ma be no (a to Send 8mans to ars in te omparati'el near &8t8reGdespite te &at tat it is entirel (itin o8r tenolo)ial apabilit$ /o'ernments do not spend tese 'ast s8ms H8st &or siene, or merel to eCplore$ e need anoter p8rpose, and it m8st make real politial sense$ It ma be impossible to )o H8st et, b8t (en it is possible, te mission, I tink, m8st be international &rom te start, (it osts and responsibilities eK8itabl sared and te eCpertise o& man nations tapped? te prie m8st be reasonable? te time &rom appro'al to la8n m8st &it (itin pratial politial timesales? and te spae a)enies onerned m8st demonstrate teir abilit to m8ster pioneerin) eCplorator missions (it 8man re(s sa&el, on time, and on b8d)et$ I& it (ere possible to ima)ine s8 a mission &or less tan Y100 billion, and &or a time &rom appro'al to la8n less tan 15 ears, mabe it (o8ld be &easible$ =In terms o& ost, tis (o8ld represent onl a &ration o& te ann8al i'ilian spae b8d)ets o& te present spae&arin) nations$< *it aerobrakin) and man8&at8rin) &8el and oC)en &or te ret8rn trip o8t o& artian air, itAs no( be)innin) to look as i& s8 a b8d)et and s8 a timesale mi)t at8all be realisti$ e eaper and K8iker te mission is, neessaril te more risk (e m8st be (illin) to take (it te li'es o& te astrona8ts and osmona8ts aboard$ B8t as is ill8strated, amon) o8ntless eCamples, b te sam8rai o& medie'al >apan, tere are al(as ompetent 'ol8nteers &or i)l 1"9
dan)ero8s missions in (at is perei'ed as a )reat a8se$ No b8d)et, no timeline an be reall reliable (en (e attempt to do sometin) on so )rand a sale, sometin) tat as ne'er been done be&ore$ e more lee(a (e ask, te )reater is te ost and te lon)er it takes to )et tere$ %indin) te ri)t ompromise bet(een politial &easibilit and mission s8ess ma be trik$ IT'S NOT ENOUGHto
)o to ars bea8se some o& 8s a'e dreamt o& doin) so sine ildood, or
bea8se it seems to 8s te ob'io8s lon)-term eCplorator )oal &or te 8man speies$ I& (eAre talkin) abo8t spendin) tis m8 mone, (e m8st H8sti& te eCpense$ ere are no( oter mattersGlear, rin) national needsGtat annot be addressed (ito8t maHor eCpendit8res? at te same time, te disretionar &ederal b8d)et as beome pain&8ll onstrained$ !isposal o& emial and radioati'e poisons, ener) e&&iien, alternati'es to &ossil &8els, delinin) rates o& tenolo)ial inno'ation, te ollapsin) 8rban in&rastr8t8re, te I!S epidemi, a (itesA bre( o& aners, omelessness, maln8trition, in&ant mortalit, ed8ation, Hobs, ealt areGtere is a pain&8ll lon) list$ I)norin) tem (ill endan)er te (ell-bein) o& te nation$ similar dilemma &aes all te spae&arin) nations$ Nearl e'er one o& tese matters o8ld ost 8ndreds o& billions o& dollars or more to address$ %iCin) in&rastr8t8re (ill ost se'eral trillion dollars$ lternati'es to te &ossil-&8el eonom learl represent a m8ltitrillion-dollar in'estment (orld(ide, i& (e an do it$ ese proHets, (e are sometimes told, are beond o8r abilit to pa$ o( ten an (e a&&ord to )o to arsD I& tere (ere "0 perent more disretionar &8nds in te $S$ &ederal b8d)et =or te b8d)ets o& te oter spae&arin) nations<, I probabl (o8ld not &eel so on&lited abo8t ad'oatin) sendin) 8mans to ars$ I& tere (ere "0 perent less, I donAt tink te most dieard spae ent8siast (o8ld be 8r)in) s8 a mission$ S8rel tere is some point at (i te national eonom is in s8 dire straits tat sendin) people to ats is 8nonsionable$ e K8estion is (ere (e dra( te line$ plainl s8 a line eCists, and e'er partiipant in tese debates so8ld stip8late (ere tat line so8ld be dra(n, (at &ration o& te )ross national prod8t &or spae is too m8$ IAd like te same tin) done &or de&ense$ 8bli opinion polls so( tat man merians tink te NS b8d)et is abo8t eK8al to te de&ense b8d)et$ In &at, te entire NS b8d)et, inl8din) 8man and roboti missions and aerona8tis, is abo8t 5 perent o& te $S$ de&ense b8d)et$ o( m8 spendin) &or de&ense at8all (eakens te o8ntrD nd e'en i& NS (ere anelled alto)eter, (o8ld (e &ree 8p (at is needed to sol'e o8r national problemsD
HUMAN SPACEFLIGHT In
)eneralGto sa notin) o& eCpeditions to arsG(o8ld be m8 more
readil s8pportable i&, as in te &i&teent-ent8r ar)8ments o& +ol8mb8s and enr te Na'i)ator, tere (ere a pro&it l8re$1 Some ar)8ments a'e been ad'aned$ e i) 'a88m or 1
E'en ten it (asnAt eas$ e ort8)8ese roniler /omes Eanes de @8rara reported tis assessment b rine enr te Na'i)ator: It seemed to te .ord In&ante tat i& e or some oter lord did not endea'or to )ain tat kno(led)e, no mariners nor merants (o8ld e'er dare to attempt it, &or it is lear tat none o& tem e'er tro8ble temsel'es to sail to a plae (ere tere is not a s8re and ertain ope o& pro&it$
130
lo( )ra'it or intense radiation en'ironment o& near-Eart spae mi)t be 8tilied, it is said, &or ommerial bene&it$ ll s8 proposals m8st be allen)ed b tis K8estion: +o8ld omparable or better prod8ts be man8&at8red do(n ere on Eart i& te de'elopment mone made a'ailable (ere omparable to (at is bein) po8red into te spae pro)ramD >8d)in) b o( little mone orporations a'e been (illin) to in'est in s8 tenolo)Gapart &rom te entities b8ildin) te rokets and spaera&t temsel'esGte prospets, at least at present, seem to be not 'er i)$ e notion tat rare materials mi)t be a'ailable else(ere is tempered b te &at tat &rei)ta)e is i)$ ere ma, &or all (e kno(, be oeans o& petrole8m on itan, b8t transportin) it to Eart (ill be eCpensi'e$ latin8m-)ro8p metals ma be ab8ndant in ertain asteroids$ I& (e o8ld mo'e tese asteroids into orbit aro8nd te Eart, peraps (e o8ld on'enientl mine tem$ B8t at least &or te &oreseeable &8t8re tis seems dan)ero8sl impr8dent, as I desribe later in tis book$ In is lassi siene &ition no'el /e Man :o Sol "e Moon obert einlein ima)ined te pro&it moti'e as te ke to spae tra'el$ e adnAt &oreseen tat te +old *ar (o8ld sell te oon$ B8t e did reo)nie tat an onest pro&it ar)8ment (o8ld be di&&i8lt to ome b$ einlein en'isioned, tere&ore, a sam in (i te l8nar s8r&ae (as salted (it diamonds so later eCplorers o8ld breatlessl diso'er tem and initiate a diamond r8s$ *eA'e sine ret8rned samples &rom te oon, to8), and tere is not a int o& ommeriall interestin) diamonds tere$ o(e'er, iosi 8ramoto and aka&8mi ats8i o& te ni'ersit o& oko a'e st8died o( te entral iron ores o& Eart, #en8s, and ars &ormed, and &ind tat te artian mantle =bet(een r8st and ore< so8ld be ri in arbonGrier tan tat o& te oon or #en8s or Eart$ !eeper tan 300 kilometers, te press8res so8ld trans&orm arbon into diamond$ *e kno( tat ars as been )eolo)iall ati'e o'er its istor$ aterial &rom )reat dept (ill oasionall be eCtr8ded 8p to te s8r&ae, and not H8st in te )reat 'olanos$ So tere does seem to be a ase &or diamonds on oter (orldsGon ars, lied not te oon$ In (at K8antities, o& (at K8alit and sie, and in (i loales (e do not et kno($ e ret8rn to Eart o& a spaera&t st8&&ed (it )or)eo8s m8ltiarat diamonds (o8ld do8btless depress pries =as (ell as te sareolders o& te de Beers and /eneral Eletri orporations<$ B8t bea8se o& te ornamental and ind8strial appliations o& diamonds, peraps tere is a lo(er limit belo( (i pries (ill not )o$ +onei'abl, te a&&eted ind8stries mi)t &ind a8se to promote te earl eCploration o& ars$ e idea tat artian diamonds (ill pa &or eCplorin) ars is at best a 'er lon) sot, b8t itAs an eCample o& o( rare and 'al8able s8bstanes ma be diso'erable on oter (orlds$ It (o8ld be &oolis, to8), to o8nt on s8 ontin)enies$ I& (e seek to H8sti& missions to oter (orlds, (eAll a'e to &ind oter reasons$
131
BEYOND DISCUS SIONS OF PROFITSand
osts, e'en red8ed osts, (e m8st also desribe
bene&its, i& te eCist$ d'oates o& 8man missions to ars m8st address (eter, in te lon) term, missions 8p tere are likel to miti)ate an o& te problems do(n ere$ +onsider no( te standard set o& H8sti&iations and see i& o8 &ind tem 'alid, in'alid, or indeterminate: 8man missions to ars (o8ld speta8larl impro'e o8r kno(led)e o& te planet, inl8din) te sear &or present and past li&e$ e pro)ram is likel to lari& o8r 8nderstandin) o& te en'ironment o& o8r o(n planet, as roboti missions a'e alread be)8n to do$ e istor o& o8r i'iliation so(s tat te p8rs8it o& basi kno(led)e is te (a te most si)ni&iant pratial ad'anes ome abo8t$ 2pinion polls s8))est tat te most pop8lar reason &or eCplorin) spae is inreased kno(led)e$ B8t are 8mans in spae essential to aie'e tis )oalD oboti missions, )i'en i) national priorit and eK8ipped (it impro'ed maine intelli)ene, seem to me entirel apable o& ans(erin), as (ell as astrona8ts an, all te K8estions (e need to askG and at abe 10 perent te ost$ It is alle)ed tat spino&& (ill transpireG8)e tenolo)ial bene&its tat (o8ld oter(ise &ail to ome abo8tGtereb impro'in) o8r international ompetiti'eness and te domesti eonom$ B8t tis is an old ar)8ment: Spend Y;0 billion =in ontemporar mone< to send pollo astrona8ts to te oon, and (eAll tro( in a &ree stikless &rin) pan$ lainl, i& (eAre a&ter &rin) pans, (e an in'est te mone diretl and sa'e almost all o& tat Y;0 billion$ e ar)8ment is speio8s &or oter reasons as (ell, one o& (i is tat !8ontAs e&lon tenolo) lon) antedated pollo$ e same is tr8e o& ardia paemakers, ballpoint pens, #elro, and oter p8rported spino&&s o& te pollo pro)ram$ =I one ad te opport8nit to talk (it te in'entor o& te ardia paemaker, (o imsel& nearl ad a oronar aident desribin) te inH8stie o& (at e perei'ed as NS takin) redit &or is de'ie$< I& tere are tenolo)ies (e 8r)entl need, ten spend te mone and de'elop tem$ * )o to ars to do itD 2& o8rse it (o8ld be impossible &or so m8 ne( tenolo) as NS reK8ires to be de'eloped and not a'e some spillo'er into te )eneral eonom, some in'entions 8se&8l do(n ere$ %or eCample, te po(dered oran)e H8ie s8bstit8te an) (as a prod8t o& te manned spae pro)ram, and spino&&s a'e o8rred in ordless tools, implanted ardia de&ibrillators, liK8idooled )arments, and di)ital ima)in)Gto name a &e($ B8t te ardl H8sti& 8man 'oa)es to ars or te eCistene o& NS$ *e o8ld see te old spino&& en)ine (eein) and p8&&in)
in te (anin) das o& te
ea)an-era Star *ars o&&ie$ dro)en bomb-dri'en -ra lasers on orbitin) battle stations (ill elp per&et laser s8r)er, te told 8s$ B8t i& (e need laser s8r)er, i& itAs a i) national priorit, b all means letAs alloate te &8nds to de'elop it$ H8st lea'e Star *ars o8t o& it$ Spino&& H8sti&iations onstit8te an admission tat te pro)ram anAt stand on its o(n t(o &eet, annot be H8sti&ied b te p8rpose &or (i it (as ori)inall sold$ 2ne 8pon a time it (as to8)t, on te basis o& eonometri models, tat &or e'er dollar in'ested in NS man dollars (ere p8mped into te $S$ eonom$ I& tis m8ltiplier e&&et applied more to NS tan to most )o'ernment a)enies, it (o8ld pro'ide a potent &isal and soial H8sti&iation &or te spae pro)ram$ NS s8pporters (ere not s abo8t appealin) to tis 13"
ar)8ment$ B8t a 1994 +on)ressional B8d)et 2&&ie st8d &o8nd it to be a del8sion$ *ile NS spendin) bene&its some prod8tion se)ments o& te $S$ eonomGespeiall te aerospae ind8strGtere is no pre&erential m8ltiplier e&&et$ .ike(ise, (ile NS spendin) ertainl reates or maintains Hobs and pro&its, it does so no more e&&iientl tan man oter )o'ernment a)enies$ en tereAs ed8ation, an ar)8ment tat as pro'ed &rom time to time 'er attrati'e in te *ite o8se$ !otorates in siene peaked some(e re aro8nd te time o& Apollo 11, mabe e'en (it te proper pase la) a&ter te start o& te pollo pro)ram$ e a8se-and-e&&et relationsip is peraps 8ndemonstrated, alto8) not impla8sible$ B8t so (atD I& (eAre interested in impro'in) ed8ation, is )oin) to ars te best ro8teD ink o& (at (e o8ld do (it Y100 billion &or teaer trainin) and salaries, sool laboratories and libraries, solarsips &or disad'anta)ed st8dents, resear &ailities, and )rad8ate &ello(sips$ Is it reall tr8e tat te best (a to promote siene ed8ation is to )o to arsD noter ar)8ment is tat 8man missions to ars (ill o8p te militar-ind8strial ompleC, di&&8sin) te temptation to 8se its onsiderable politial m8sle to eCa))erate eCternal treats and p8mp 8p de&ense &8ndin)$ e oter side o& tis parti8lar oin is tat b )oin) to ars (e maintain a standb tenolo)ial apait tat mi)t be important &or &8t8re militar ontin)enies$ 2& o8rse, (e mi)t simpl ask tose )8s to do sometin) diretl 8se&8l &or te i'ilian eonom$ B8t as (e sa( in te 1970s (it /r8mman b8ses and Boein)#ertol omm8ter trains, te aerospae ind8str eCperienes real di&&i8lt in prod8in) ompetiti'el &or te i'ilian eonom$ +ertainl a tank ma tra'el 1,000 miles a ear and a b8s 1,000 miles a (eek, so te basi desi)ns m8st be di&&erent$ B8t on matters o& reliabilit at least, te !e&ense !epartment seems to be m8 less demandin)$ +ooperation in spae, as IA'e alread mentioned, is beomin) an instr8ment o& international ooperationG&or eCample, in slo(in) te proli&eration o& strate)i (eapons to ne( nations$ okets deommissioned bea8se o& te end o& te +old *ar mi)t be )ain&8ll emploed in missions to Eart orbit, te oon, te planets, asteroids, and omets$ B8t all tis an be aomplised (ito8t 8man missions to ars$ 2ter H8sti&iations are o&&ered$ It is ar)8ed tat te 8ltimate sol8tion to (orld ener) problems is to strip-mine te oon, ret8rn te solar-(ind-implanted eli8m-3 bak to Eart, and 8se it in &8sion reators$ *at &8sion reatorsD E'en i& tis (ere possible, e'en i& it (ere oste&&eti'e, it is a tenolo) 50 or 100 ears a(a$ 28r ener) problems need to be sol'ed at a less leis8rel pae$ E'en stran)er is te ar)8ment tat (e a'e to send 8man bein)s into spae in order to sol'e te (orld pop8lation risis$ B8t some "50,000 more people are born tan die e'er daG (i means ans tat (e (o8ld a'e to la8n "50,000 people per da into spae to maintain (orld pop8lation at its present le'els$ is appears to be beond o8r present apabilit$
133
I RUN THROUGH s8
a list and tr to add 8p te pros and ons, bearin) in mind te oter
8r)ent laims on te &ederal b8d)et$ o me, te ar)8ment so &ar omes do(n to tis K8estion: +an te s8m o& a lar)e n8mber o& indi'id8all inadeK8ate >8sti&iations add 8p to an adeK8ate H8sti&iationD I donAt tink an o& te items on m list o& p8rported H8sti&iations is demonstrabl (ort Y500 billion or e'en Y100 billion, ertainl not in te sort term$ 2n te oter and, most o& tem are (ort sometin), and i& I a'e &i'e items ea (ort Y"0 billion, mabe it adds 8p to Y100 billion$ I& (e an be le'er abo8t red8in) osts and makin) tr8e international partnersips, te H8sti&iations beome more ompellin)$ ntil a national debate on tis topi as transpired, 8ntil (e a'e a better idea o& te rationale and te ostbene&it ratio o& 8man missions to ars, (at so8ld (e doD s8))estion is tat (e p8rs8e resear and de'elopment proHets tat an be H8sti&ied on teir o(n merits or b teir rele'ane to oter )oals, b8t tat an also ontrib8te to 8man missions to ars so8ld (e later deide to )o$ S8 an a)enda (o8ld inl8de:
Z $S$ astrona8ts on te 8ssian spae station Mir &or Hoint &li)ts o& )rad8all inreasin) d8ration, aimin) at one to t(o ears, te ars &li)t time$ Z +on&i)8ration o& te international spae station so its prinipal &8ntion is to st8d te lon)-term e&&ets o& te spae en'ironment on 8mans$ Z Earl implementation o& a rotatin) or tetered arti&iial )ra'it mod8le on te international spae station, &or oter animals and ten &or 8mans$ Z Enaned st8dies o& te S8n, inl8din) a distrib8ted set o& robot probes in orbit abo8t te S8n, to monitor solar ati'it and )i'e te earliest possible (arnin) to astrona8ts o& aardo8s solar &laresGmass eHetions o& eletrons and protons &rom te S8nAs orona$ Z $S$8ssian and m8ltilateral de'elopment o& Energi$a and Pro"on roket tenolo) &or te $S$ and international spae pro)rams$ lto8) te nited States is 8nlikel to depend primaril on a So'iet booster, Energi$a as ro8)l te li&t o& te Sa"urn V tat sent te pollo astrona8ts to te oon$ e nited States let te Sa"urn V assembl line
Pro"on i te most reliable lar)e booster no( in die, and 8ssia it annot res8sitated$ ser'ie$ is readil ea)er tobe sell tis tenolo) &or ard 8rren$ Z >oint proHets (it NS!=te >apanese spae a)en< and oko ni'ersit, te E8ropean Spae )en, and te 8ssian Spae )en, alon) (it +anada and oter nations$ In most ases tese so8ld be eK8al partnersips, not te nited States insistin) on allin) te sots$ %or te roboti eCploration o& ars, s8 pro)rams are alread 8nder (a$ %or 8man &li)t, te ie& s8 ati'it is learl te international spae station$ E'ent8all, (e mi)t m8ster Hoint sim8lated planetar missions in lo( Eart orbit$ 2ne o& te prinipal obHeti'es o& tese pro)rams so8ld be to b8ild a tradition o& ooperati'e tenial eCellene$ Z enolo)ial de'elopmentG8sin) state-o&-te-art robotis and arti&iial intelli)eneG o& ro'ers, balloons, and airra&t &or te eCploration o& ars, and implementation o& te &irst international ret8rn sample mission$ oboti spaera&t tat an ret8rn samples &rom
134
ars an be tested on near-Eart asteroids and te oon$ Samples ret8rned &rom are&8ll seleted re)ions o& te oon an a'e teir a)es determined and ontrib8te in a &8ndamental (a to o8r 8nderstandin) o& te earl istor o& te Eart$ Z %8rter de'elopment o& tenolo)ies to man8&at8re &8el and oCidier o8t o& artian materials$ In one estimate, based on a prototpe instr8ment desi)ned b obert @8brin and ollea)8es at te artin arietta +orporation, se'eral kilo)rams o& artian soil an be a8tomatiall ret8rned to Eart 8sin) a modest and reliable !elta la8n 'eile, all &or no more tan a son) =omparati'el speakin)<$ Z Sim8lations on Eart o& lon)-d8ration trips to ars, onentratin) on potential soial and psolo)ial problems$ Z #i)oro8s p8rs8it o& ne( tenolo)ies s8 as onstant-tr8st prop8lsion to )et 8s to ars K8ikl? tis ma be essential i& te radiation or miro)ra'it aards make oneear =or lon)er< &li)t times too risk$ Z Intensi'e st8d o& near-Eart asteroids, (i ma pro'ide s8perior intermediatetimesale obHeti'es &or 8man eCploration tan does te oon$ Z )reater empasis on sieneGinl8din) te &8ndamental sienes beind spae eCploration, and te toro8) analsis o& data alread obtainedGb NS and oter spae a)enies$
ese reommendations add 8p to a &ration o& te &8ll ost o& a 8man mission to ars and Gspread o8t o'er a deade or so and done Hointl (it oter nationsGa &ration o& 8rrent spae b8d)ets$ B8t, i& implemented, te (o8ld elp 8s to make a8rate ost estimates and better assessment o& te dan)ers and bene&its$ e (o8ld permit 8s to maintain 'i)oro8s pro)ress to(ard 8man eCpeditions to ars (ito8t premat8 re ommitment to an spei&i missio n ard(are$ ost, peraps all, o& tese reommendations a'e oter H8sti&iations, e'en i& *e (ere s8re (ed be 8nable to send 8mans to an oter (orld in te neCt &e( deades$ nd a stead dr8mbeat o& aomplisments inreasin) te &easibilit o& 8man 'oa)es to ars (o8ldGin te minds o& man at leastGombat (idespread pessimism abo8t te &8t8re$
THERE'S SOMETHING MORE ) ereAs
a set o& less tan)ible ar)8ments, man o& (i, I &reel
admit, I &ind attrati'e and resonant$ Spae&li)t speaks to sometin) deep inside 8sGman o& 8s, i& not all$ n emer)in) osmi perspeti'e, an impro'ed 8nderstandin) o& o8r plae in te ni'erse, a i)l 'isible pro)ram a&&etin) o8r 'ie( o& o8rsel'es mi)t lari& te &ra)ilit o& o8r planetar en'iro nment and te ommon peril and responsibilit o& all te nations and peoples o& Eart$ nd 8man missions to ars (o8ld pro'ide ope&8l prospets, ri in ad'ent8re, &or te (anderers amon) 8s, espeiall te o8n)$ E'en 'iario8s eCploration as soial 8tilit$ I repeatedl &ind tat (en I )i'e talks on te &8t8re o& te spae pro)ramGto 8ni'ersities, b8siness and militar )ro8ps, pro&essional or)aniationsGte a8dienes are m8 less patient (it pratial, real-(orld politial and eonomi obstales tan 1$ e lon) to s(eep a(a te
135
impediments, to reapt8re te )lor das o& #ostok and pollo, to )et on (it it and one more tread oter (orlds$ *e did it be&ore? (e an do it a)ain, te sa$ B8t, I a8tion msel&, tose (o attend s8 talks are sel&-seleted spae ent8siasts$ In 1969, less tan al& te merian people to8)t te pollo pro)ram (as (ort te ost$ B8t on te t(ent-&i&t anni'ersar o& te oon landin), te n8mber ad risen to t(o tirds$ !espite its probl ems, NS (as rated as doin) a )ood-to-eCellent Hob b 63 perent o& merians$ *it no re&erene to ost, 75 perent o& merians =aordin) to a +BS Ne(s poll< &a'ored te nited States sendin) astrona8ts to eCplore ars$A %or o8n) ad8lts, te &i)8re (as 6; perent$ I tink eCplore is te operati'e (ord$ It is no aident tat, (ate'er teir 8man &la(s, and o( e'er morib8nd te 8man spae pro)ram as beome =a trend tat te 8bble Spae elesope repair mission ma a'e elped to re'erse<, astrona8ts and osmona8ts are still (idel re)arded as eroes o& o8r speies$ sienti&i ollea)8e tells me abo8t a reent trip to te Ne( /8inea i)lands (ere se 'isited a stone a)e 8lt8re ardl ontated b *estern i'iliation$ e (ere i)norant o& (rist(ates, so&t drinks, and &roen &ood$ B8t te kne( abo8t pollo 11$ e kne( tat 8mans ad (alked on te oon$ e kne( te names o& rmstron) and ldrin and +ollins$ e (anted to kno( (o (as 'isitin) te oon tese das$ roHets tat are &8t8re-oriented, tat, despite teir politial di&&i8lties, an be ompleted onl in some distant deade are ontin8in) reminders tat tere (ill be a &8t8re$ *innin) a &ootold on oter (orlds (ispers in o8r ears tat (eAre more tan its or Serbs or on)ans: *eAre 8mans$ ECplorator spae&li)t p8ts sienti&i ideas, sienti&i tinkin), and sienti&i 'oab8lar in te p8bli ee$ It ele'ates te )eneral le'el o& intellet8al inK8ir$ e idea tat (eA'e no( 8nderstood sometin) ne'er )rasped b anone (o e'er li'ed be&oreGtat eCilaration, espeiall intense &or te sientists in'ol'ed, b8t pereptible to nearl e'eroneGpropa)ates tro8) te soiet, bo8nes o&& (alls, and omes bak at 8s$ It eno8ra)es 8s to address problems in oter &ields tat a'e also ne'er be&ore been sol'ed$ It inreases te )eneral sense o& optimism in te soiet$ It )i'es 8rren to ritial tinkin) o& te sort 8r)entl needed i& (e are to sol'e iterto intratable soial iss8es$ It elps stim8late a ne( )eneration o& sientists$ e more siene in te media-espeiall i& metods are desribed, as (ell as onl8sions and impliations-te ealtier, I belie'e, te soiet is$ eople e'er(ere 8n)er to 8nderstand$ WHEN I WAS A CHILD , m
most eC8ltant dreams (ere abo8t &lin)Gnot in some maine, b8t all
b msel&$ I (o8ld be skippin) or oppin), and slo(l I o8ld p8ll m traHetor i)er$ It (o8ld take lon)er to &all bak to te )ro8nd$ Soon I (o8ld be on s8 a i) ar tat I (o8ldnAt ome do(n at all$ I (o8ld ali)t like a )ar)ole in a nie near te pinnale o& a sksraper, or )entl settle do(n on a lo8d$ In te dreamG(i I m8st a'e ad in its man 'ariations at least a 8ndred timesGaie'in) &li)t reK8ired a ertain ast o& mind$ ItAs impossible to desribe it in (ords, b8t I an remember (at it (as like to tis da$ o8 did sometin) inside o8r ead and at te pit o& o8r stoma, and ten o8 o8ld li&t o8rsel& 8p b an e&&ort o& (ill alone, o8r limbs an)in) limpl$ 2&& o8Ad soar$ 136
I kno( man people a'e ad similar dreams$ abe most people$ abe e'erone$ eraps it )oes bak 10 million ears or more, (en o8r anestors (ere )rae&8ll &lin)in) temsel'es &rom bran to bran in te prime'al &orest$ (is to soar like te birds moti'ated man o& te pioneers o& &li)t, inl8din) .eonardo da #ini and te *ri)t broters$ abe tatAs part o& te appeal o& spae&li)t, too$ In orbit abo8t an (orld, or in interplanetar &li)t, o8 are literall (ei)tless$ o8 an propel o8rsel& to te spaera&t eilin) (it a sli)t p8s o&& te &loor$ o8 an )o t8mblin) tro8) te air do(n te lon) aCis o& te spaera&t$ 8mans eCperiene (ei)tlessness as Ho? tis as been reported b almost e'er astrona8t and osmona8t$ B8t bea8se spaera&t are still so small, and bea8se spae (alks a'e been done (it eCtreme a8tion, no 8man as et enHoed tis (onder and )lor: propellin) o8rsel& b an almost impereptible p8s, (it no mainer dri'in) o8, 8ntetered, i) 8p into te sk, into te blakness o& interplanetar spae$ o8 beome a li'in) satellite o& te Eart, or a 8man planet o& te S8n$ lanetar eCploration satis&ies o8r inlination &or )reat enterprises and (anderin)s and K8ests tat as been (it 8s sine o8r das as 8nters and )at erers on te East &r ian sa'annas a million ears a)o$ B aneGit is possible, I sa, to ima)ine man skeins o& istorial a8salit in (i tis (o8ld not a'e transpiredGin o8r a)e (e are able to be)in a)ain$ ECplorin) oter (orlds emplos preisel te same K8alities o& darin), plannin), ooperati'e enterprise, and 'alor tat mark te &inest in te militar tradition$ Ne'er mind te ni)t la8n o& an pollo spaera&t bo8nd &or anoter (orld$ at makes te onl8sion &ore)one$ *itness mere %-14s takin) o&& &rom adHaent &li)t deks, )rae&8ll antin) le&t and ri)t, a&terb8rners &lamin), and tereAs sometin) tat s(eeps o8 a(aGor at least it does me$ nd no amo8nt o& kno(led)e o& te potential ab8ses o& arrier task &ores an a&&et te dept o& tat &eelin)$ It simpl speaks to anoter part o& me$ It doesnAt (ant reriminations or politis$ It H8st (ants to &l$ I $ $ $ ad ambition not onl to )o &arter tan anone ad done be&ore, (rote +aptain >ames +ook, te ei)teent-ent8r eCplorer o& te ai&i, b8t as &ar as it (as possible &or man to )o$ (o ent8ries later, 8ri omanenko, on ret8rnin) to Eart a&ter (at (as ten te lon)est spae &li)t in istor, said e +osmos is a ma)net $ $ $ 2ne o8A'e been tere, all o8 an tink o& is o( to )et bak$ E'en >ean->aK8es o8ssea8, no ent8siast o& tenolo), &elt it: e stars are &ar abo'e 8s? (e need preliminar instr8tion, instr8ments and maines, (i are like so man immense ladders enablin) 8s to approa tem and brin) tem (itin o8r )rasp$
e &8t8re possibilities o& spae-tra'el, (rote te pilosoper Bertrand 8ssell in 1959, (i are no( le&t mainl to 8n&o8nded &antas, o8ld be more soberl treated (ito8t easin) to be interestin) and o8ld so( to e'en te most ad'ent8ro8s o& te o8n) tat a (orld (ito8t (ar
137
need not be a (orld (ito8t ad'ent8ro8s and aardo8s )lor$1 o tis kind o& ontest tere is no limit$ Ea 'itor is onl a prel8de to anoter, and no bo8ndaries an be set to rational ope$
In te lon) r8n, teseGmore tan an o& te pratial H8sti&iations onsidered earlierG ma be te reasons (e (ill )o to ars and oter (orlds$ In te meantime, te most important step (e an take to(ard ars is to make si)ni&iant pro)ress on Eart$ E'en modest impro'ements in te soial, eonomi, and politial problems tat o8r )lobal i'iliation no( &aes o8ld release enormo8s reso8res, bot material and 8man, &or oter )oals$ ereAs plent o& o8se(ork to be done ere on Eart, and o8r ommitment to it m8st be stead&ast$ B8t (eAre te kind o& speies tat needs a &rontierG&or &8ndamental biolo)ial reasons$ E'er time 8manit stretes itsel& and t8rns a ne( orner, it reei'es a Holt o& prod8ti'e 'italit tat an arr it &or ent8ries$ ereAs a ne( (orld neCt door$ nd (e kno( o( to )et tere$
C
H
A
P
T
E
R
17
2INE 1
8ssellAs prase is note(ort: ad'ent8ro8s and aardo8s )lor$ E'en i& (e o8ld make 8man spae&li)t risk-&ree-and o& o8rse (e annot-it mi)t be o8nterprod8ti'e$ e aard is an inseparable omponent o& te )lor$
13;
INE.NE #I2.EN+E It is a la( o& nat8re tat Eart and all oter bodies so8ld remain in teir proper plaes and be mo'ed &rom tem onl b 'iolene$ GIS2.E =3;4-3"" B$+$<, SI+S
Tere (as
sometin) &8nn abo8t Sat8rn$ *en, in 1610, /alileo 8sed te (orldAs &irst
astronomial telesope to 'ie( te planetGten te most distant (orld kno(nGe &o8nd t(o appenda)es, one on eiter side$ e likened tem to andles$ 2ter astronomers alled tem ears$ e +osmos olds man (onders, b8t a planet (it H8) ears is dismain)$ /alileo (ent to is )ra'e (it tis biarre matter 8nresol'ed$ s te ears passed, obser'ers &o8nd te ears $ $ $ *ell, (aCin) and (anin)$ E'ent8all, it beame lear tat (at /alileo ad diso'ered (as an eCtremel tin rin) tat s8rro8nds Sat8rn at its eK8ator b8t to8es it no(ere$ In some ears, bea8se o& te an)in) orbital positions o& Eart and Sat8rn, te rin) ad been seen ed)e-on and, bea8se o& its tinness, it seemed to disappear$ In oter ears, it ad been 'ie(ed more &ae-oil, and te ears )re( bi))er$ B8t (at does it mean tat tereAs a rin) aro8nd Sat8rnD tin, &lat, solid plate (it a ole 8t o8t &or te planet to &it intoD *ere does "a" ome &romD is line o& inK8ir (ill sortl take 8s to (orld-satterin) ollisions, to t(o K8ite di&&erent perils &or o8r speies, and to a reasonGbeond tose alread desribedGtat (e m8st, &or o8r 'er s8r'i'al, be o8t tere amon) te planets$ *e no( kno( tat te rin)s =empatiall pl8ral< o& Sat8rn are a 'ast orde o& tin ie (orlds, ea on its separate orbit, ea bo8nd to Sat8rn b te )iant planetAs )ra'it$ In sie, tese (orldlets ran)e &rom partiles o& &ine d8st to o8ses$ None is bi) eno8) to poto)rap e'en &rom lose &lbs$ Spaed o8t in an eCK8isite set o& &ine onentri irles, sometin) like
139
te )roo'es on a pono)rap reord =(i in realit make, o& o8rse, a spiral<, te rin)s (ere &irst re'ealed in teir tr8e maHest b te t(o Vo$ager spaera&t in teir 19;0;1 &lbs$ In o8r ent8r, te rt !eo rin)s o& Sat8rn a'e beome an ion o& te &8t8re$ t a sienti&i meetin) in te late 1960s, I (as asked to s8mmarie te o8tstandin) problems in planetar siene$ 2ne, I s8))ested, (as te K8estion o& (, o& all te planets, onl Sat8rn ad rin)s$ is, Vo$ager diso'ered, is a nonK8estion$ All our )iant planets in o8r Solar SstemG >8piter, Sat8rn, ran8s, and Nept8neGin &at a'e rin)s$ B8t no one kne( it ten$ Ea rin) sstem as distinti'e &eat8res$ >8piterAs is ten8o8s and made mainl o& dark, 'er small partiles$ e bri)t rin)s o& Sat8rn are omposed mainl o& &roen (ater? tere are to8sands o& separate rin)s ere, some t(isted, (it stran)e, d8sk, spoke-like markin)s &ormin) and dissipatin)$ e dark rin)s o& ran8s seem to be omposed o& elemental arbon and or)ani mole8lesGsometin) like aroal or imne soot? ran8s as nine main rin)s, a &e( o& (i sometime seem to breate, eCpandin) and ontratin)$ Nept8neAs rin)s are te most ten8o8s o& all, 'arin) so m8 in tikness tat, (en deteted &rom Eart, te appear onl as ars and inomplete irles$ n8mber o& rin)s seem to be maintained b te )ra'itational t8)s o& t(o seperd moons, one a little nearer and te oter a little &arter &rom te planet tan te rin)$ Ea rin) sstem displas its o(n, appropriatel 8neartl, bea8t$ o( do rin)s &ormD 2ne possibilit is tides: I& an errant (orld passes lose to a planet, te interloperAs near side is )ra'itationall p8lled to(ard te planet more tan its &ar side? i& it omes lose eno8), i& its internal oesion is lo( eno8), it an be literall torn to piees$ 2asionall (e see tis appenin) to omets as te pass too lose to >8piter, or te S8n$ noter possibilit, emer)in) &rom te Vo$ager reonnaissane o& te o8ter Solar Sstem, is tis: in)s are made (en (orlds ollide and moons are smased to smitereens$ Bot meanisms ma a'e plaed a role$ e spae bet(een te planets is tra'ersed b an odd olletion o& ro)8e (orldlets, ea in orbit abo8t te S8n$ &e( are as bi) as a o8nt or e'en a state? man more a'e s8r&ae areas like tose o& a 'illa)e or a to(n$ ore little ones are &o8nd tan bi) ones, and te ran)e in sie do(n to partiles o& d8st$ Some o& tem tra'el on lon), streted-o8t elliptial pats, (i make tem periodiall ross te orbit o& one or more planets$ 2asionall, 8nl8kil, tereAs a (orld in te (a$ e ollision an satter and p8l'erie bot te interloper and te moon tatAs it =or at least te re)ion aro8nd )ro8nd ero<$ e res8ltin) debrisGeHeted &rom te moon b8t not so &ast-mo'in) as to esape &rom te planetAs )ra'itGma &orm, &or a time, a ne( rin)$ ItAs made o& (ate'er te ollidin) bodies (ere made o&, b8t 8s8all more o& te tar)et moon tan te ro)8e impator$ I& te ollidin) (orlds are i, te net res8lt (ill be rin)s o& ie partiles? i& teAre made o& or)ani mole8les, te res8lt (ill be rin)s o& or)ani partiles =(i (ill slo(l be proessed b radiation into arbon<$ ll te mass in te rin)s o& Sat8rn is no more tan A(o8ld res8lt &rom te omplete impat p8l'eriation o& a sin)le i moon$ e disinte)ration o& small moons an like(ise ao8nt &or te rin) sstems o& te tree oter )iant planets$
140
nless itAs 'er lose to its planet, a sattered moon )rad8all rea8m8lates =or at least a &air &ration o& it does<$ e piees, bi) and small, still in approCimatel te same orbit as te moon (as be&ore te impat, &all to)eter elter-skelter$ *at 8sed to be a piee o& te ore is no( at te s8r&ae, and 'ie 'ersa$ e res8ltin) od)epod)e s8r&aes mi)t seem 'er odd$ iranda, one o& te moons o& ran8s, looks disonertin)l H8mbled and ma a'e ad s8 an ori)in$ e merian planetar )eolo)ist E8)ene Soemaker proposes tat man moons in te o8ter Solar Sstem a'e been anniilated and re&ormedGnot H8st one b8t se'eral times ea o'er te 4$5 billion ears sine te S8n and te planets ondensed o8t o& interstellar )as and d8st$ e pit8re emer)in) &rom te Vo$ager reonnaissane o& te o8ter Solar Sstem is o& (orlds (ose plaid and lonel 'i)ils are spasmodiall tro8bled b interlopers &rom spae? o& (orldsatterin) ollisions? and o& moons re-&ormin) &rom debris, reonstit8tin) temsel'es like poeniCes &rom teir o(n ases$ B8t a moon tat li'es 'er lose to a planet annot re-&orm i& it is p8l'eriedGte )ra'itational tides o& te nearb planet pre'ent it$ e res8ltin) debris, one spread o8t into a rin) sstem, mi)t be 'er lon)-li'edGat least b te standard o& a 8man li&etime$ eraps man o& te small, inonspi8o8s moons no( orbitin) te )iant planets (ill one da blossom &ort into 'ast and lo'el rin)s$ ese ideas are s8pported b te appearane o& a n8mber o& satellites in te Solar Sstem$ obos, te inner moon o& ars, as a lar)e rater named Stikne? imas, an inner moon o& Sat8rn, as a bi) one named ersel$ ese ratersGlike tose on o8r o(n oon and, indeed, tro8)o8t te Solar SstemGare prod8ed b ollisions$ n interloper smases into a bi))er (orld and makes an immense eCplosion at te point o& impat, bo(l-saped rater is eCa'ated, and te smaller impatin) obHet is destroed$ I& te interlopers tat d8) o8t te Stikne and ersel raters ad been onl a little lar)er, te (o8ld a'e ad eno8) ener) to blo( obos and imas to bits$ ese moons barel esaped te osmi (rekin) ball$ an oters did not$ E'er time a (orld is smased into, tereAs one less interloperGsometin) like a demolition derb on te sale o& te Solar Sstem, a (ar o& attrition$ e 'er &at tat man s8 ollisions a'e o8rred means tat te ro)8e (orldlets a'e been lar)el 8sed 8p$ ose on ir8lar traHetories aro8nd te S8n, tose tat donAt interset te orbits o& oter (orlds, (ill be 8nlikel to smas into a planet$ ose on i)l elliptial traHetories, tose tat ross te orbits o& oter planets, *ill sooner or later ollide or, b a near miss, be )ra'itationall eHeted &rom te Solar Sstem$ e planets almost ertainl a8m8lated &rom (orldlets (i in t8rn ad ondensed o8t o& a )reat &lat lo8d o& )as and d8st S8rro8ndin) te S8nGte sort o& lo8d tat an no( be seen aro8nd o8n) nearb stars$ So, in te earl istor o& te solar Sstem be&ore ollisions leaned tin)s 8p, tere so8ld a'e been man more (orldlets tan (e see toda$ Indeed, tere is lear e'idene &or tis in o8r o(n bakard: I& (e o8nt 8p te interloper (orldlets in o8r nei)borood in spae, (e an estimate o( o&ten teAll it te oon$ .et 8s make te 'er modest ass8mption tat te pop8lation o& interlopers as ne'er been smaller tan 141
it is toda$ *e an ten al8late o( man raters tere so8ld be on te oon$ e n8mber (e &i)8re t8rns o8t to be m8 less tan te n8mber (e see on te oonAs ra'a)ed i)lands$ e 8neCpeted pro&8sion o& raters on te oon speaks to 8s o& an earlier epo (en te Solar Sstem (as in (ild t8rmoil, 8rnin) (it (orlds on ollision traHetories$ is makes )ood sense, bea8se te &ormed &rom te a))re)ation o& m8 smaller (orldletsG(i temsel'es ad )ro(n o8t o& interstellar d8st$ %o8r billion ears a)o, te l8nar impats (ere 8ndreds o& times more &reK8ent tan te are toda? and 4$5 billion ears a)o, (en te planets (ere still inomplete, ollisions appened peraps a billion times more o&ten tan in o8r bealmed epo$ e aos ma a'e been relie'ed b m8 more &lamboant rin) sstems tan )rae te planets toda$ I& te ad small moons in tat time, te Eart, ars, and te oter small planets ma also a'e been adorned (it rin)s$ e most satis&ator eCplanation o& te ori)in o& o8r o(n oon, based on its emistr =as re'ealed b samples ret8rned &rom te Apollo missions<, is tat it (as &ormed almost 4$5 billion ears a)o, (en a (orld te sie o& ars str8k te Eart$ 8 o& o8r planetAs rok mantle (as red8ed to d8st and ot )as and blasted into spae$ Some o& te debris, in o:-bit aro8nd te Eart, ten )rad8all rea8m8latedGatom b atom, bo8lder b bo8lder$ I& tat 8nkno(n impatin) (orld ad been onl a little lar)er, te res8lt (o8ld a'e been te obliteration o& te Eart$ eraps tere one (ere oter (orlds in o8r Solar SstemGperaps e'en (orlds on (i li&e (as stirrin)Git b some demon (orldlet, 8tterl demolised, and o& (i toda (e a'e not e'en an intimation$ e emer)in) pit8re o& te earl Solar Sstem does not resemble a statel pro)ression o& e'ents desi)ned to &orm te Eart$ Instead, it looks as i& o8r planet (as made, and s8r'i'ed, b mere l8k ane,1 amid 8nbelie'able 'iolene$ 28r (orld does not seem to a'e been s8lpted b a master ra&tsman$ ere too, tere is no int o& a ni'erse made &or 8s$
o& (orldlets THE DWINDLING SUPPLY
is toda 'ario8sl labeled: asteroids, omets, small moons$
B8t tese are arbitrar ate)oriesGreal (orldlets are able to brea tese 8man-made partitions$ Some asteroids =te (ord means starlike, (i te ertainl are not< are rok, oters metalli, still oters ri in or)ani matter$ None is bi))er tan 1,000 kilometers aross$ e are &o8nd mainl in a belt bet(een te orbits o& ars and >8piter$ stronomers one to8)t te main-belt asteroids (ere te remains o& a demolised (orld, b8t, as IA'e been desribin), anoter idea is no( more &asionable: e Solar Sstem (as one &illed (it asteroid-like (orlds, some o& (i (ent into b8ildin) te planets$ 2nl in te asteroid belt, near >8piter, did te )ra'itational tides o& tis most massi'e planet pre'ent te nearb debris &rom oalesin) into a ne( (orld$ e asteroids, instead o& representin) a (orld tat one (as, seem to be te b8ildin) bloks o& a (orld destined ne'er to be$
1
I& it ad not, peraps tere (o8ld toda be anoter planet, a little nearer to or &arter &rom te S8n, on (i oter, K8ite di&&erent bein)s (o8ld be trin) to reonstr8t "eir ori)ins$
14"
!o(n to kilometer sie, tere ma be se'eral million asteroids, b8t, in te enormo8s 'ol8me o& interplanetar spae, e'en tatAs still &ar too &e( to a8se an serio8s aard to spaera&t on teir (a to te o8ter Solar Sstem$ e &irst main-belt asteroids, /aspra and Ida, (ere poto)raped, in 1991 and 1993 respeti'el, b te %alileo spaera&t on its tort8o8s Ho8rne to >8piter$ ain-belt asteroids mostl sta at ome$ o in'esti)ate tem$ (e m8st )o and 'isit tem, as
%alileo did$ +omets, on te oter and, sometimes ome and 'isit 8s, as alleAs +omet did most reentl in 1910 and 19;6$ +omets are made mainl o& ie, pl8s smaller amo8nts o& rok and or)ani material$ *en eated, te ie 'apories, &ormin) te lon) and lo'el tails blo(n o8t(ard b te solar (ind and te press8re o& s8nli)t$ &ter man passa)es b te S8n, te ie is all e'aporated, sometimes lea'in) a dead rok and or)ani (orld$ Sometimes te remainin) partiles, te ie tat eld tem to)eter no( )one, spread o8t in te ometAs orbit, )eneratin) a debris trail aro8nd te S8n$ E'er time a bit o& ometar &l8&& te sie o& a )rain o& sand enters te EartAs atmospere at i) speed, it b8rns 8p, prod8in) a momentar trail o& li)t tat Eartbo8nd obser'ers all a sporadi meteor or sootin) star$ Some disinte)ratin) omets a'e orbits tat ross te EartAs$ So e'er ear, te Eart, on its stead ir8mna'i)ation o& te S8n, also pl8n)es tro8) belts o& orbitin) ometar debris$ *e ma ten (itness a meteor so(er, or e'en a meteor stormGte skies ablae (it te bod parts o& a omet$ %or eCample, te erseid meteors, seen on or abo8t 8)8st 1" o& ea ear, ori)inate in a din) omet alled S(i&t-8ttle$ B8t te bea8t o& a meteor so(er so8ld not deei'e 8s: ere is a ontin88m tat onnets tese simmerin) 'isitors to o8r ni)t skies (it te destr8tion o& (orlds$ &e( asteroids no( and ten )i'e o&& little p8&&s o& )as or e'en &orm a temporar tail, s8))estin) tat te are in transition bet(een ometdom and asteroidood$ Some small moons )oin) aro8nd te planets are probabl apt8red asteroids or omets? te moons o& ars and te o8ter satellites o& >8piter ma be in tis ate)or$ /ra'it smoots do(n e'ertin) tat stiks o8t too &ar$ B8t onl in lar)e bodies is te )ra'it eno8) to make mo8ntains and oter proHetions ollapse o& teir o(n (ei)t, ro8ndin) te (orld$ nd, indeed, (en (e obser'e teir sapes, almost al(as (e &ind tat small (orldlets are l8mp, irre)8lar, potato-saped$
THERE ARE ASTRONOMERS (ose
idea o& a )ood time is to sta 8p till da(n on a old,
moonless ni)t takin) pit8res o& te skGte same sk te poto)raped te ear be&ore $ $ $ and te ear be&ore tat$ I& te )ot it ri)t last time, o8 mi)t (ell ask, ( are te doin) it a)ainD e ans(er is: e sk an)es$ In an )i'en ear tere mi)t be (orldlets (oll 8nkno(n, ne'er seen be&ore, tat approa te Eart and are spied b tese dediated obser'ers$ 2n ar "5, 1993, a )ro8p o& asteroid and omet 8nters, lookin) at te poto)rapi ar'est &rom an intermittentl lo8d ni)t at o8nt alomar in +ali&ornia, diso'ered a &aint elon)ated sm8d)e on teir &ilms$ It (as near a 'er bri)t obHet in te sk, te planet >8piter$ +aroln and E8)ene Soemaker and !a'id .e' ten asked oter obser'ers to take a look$ e
143
sm8d)e t8rned o8t to be sometin) astonisin): some t(ent small, bri)t obHets orbitin) >8piter, one beind te oter, like pearls on a strin)$ +olleti'el te are alled +omet Soemaker-.e' 9 =tis is te nint time tat tese ollaborators a'e to)eter diso'ered a periodi omet<$ B8t allin) tese obHets a omet is on&8sin)$ ere (as a orde o& tem, probabl te &ra)mented remains o& a sin)le, iterto 8ndiso'ered, omet$ It silentl orbited te S8n &or 4 billion ears be&ore passin) too lose to >8piter and bein) apt8red, a &e( deades a)o, b te )ra'it o& te Solar SstemAs lar)est planet$ 2n >8l 7, 199", it (as torn apart b >8piterAs )ra'itational tides$ o8 an reo)nie tat te inner part o& s8 a omet (o8ld be p8lled to(ard >8piter a little more stron)l tan te o8ter part, bea8se te inner part is loser to >8piter tan te o8ter part$ e di&&erene in p8ll is ertainl small$ 28r &eet are a little loser to te enter o& te Eart tan o8r eads, b8t (e are not in onseK8ene torn to piees b te EartAs )ra'it$ %or s8 tidal disr8ption to a'e o8rred, te ori)inal omet m8st a'e been eld to)eter 'er (eakl$ Be&ore &ra)mentation, it (as, (e tink, a loosel onsolidated mass o& ie, rok, and or)ani matter, mabe 10 kilometers =abo8t 6 miles< aross$ e orbit o& tis disr8pted omet (as ten determined to i) preision$ Bet(een >8l 16 and "", 1994, all te ometar &ra)ments, one a&ter anoter, ollided (it >8piter$ e bi))est piees seem to a'e been a &e( kilometers aross$ eir impats (it >8piter (ere speta8lar$ No one kne( be&oreand (at tese m8ltiple impats into te atmospere and lo8ds o& >8piter (o8ld do$ eraps te ometar &ra)ments, s8rro8nded b alos o& d8st, (ere m8 smaller tan te seemed$ 2r peraps te (ere not oe rent bodies at all,
b8t loosel
onsolidatedGsometin) like a eap o& )ra'el (it all te partiles tra'elin) tro8) spae to)eter, in nearl idential orbits$ I& eiter o& tese possibilities (ere tr8e >8piter mi)t s(allo( te omets (ito8t a trae$ 2ter astronomers to8)t tere (o8ld at least be bri)t &ireballs and )iant pl8mes as te ometar &ra)ments pl8n)ed into te atmospere$ Still oters s8))ested tat te dense lo8d o& &ine partiles aompanin) te &ra)ments o& +omet Soemaker-.e' 9 into >8piter (o8ld disr8pt te ma)netospere o& >8piter or &orm a ne( rin)$ omet tis sie so8ld impat >8piter, it is al8lated, onl one e'er to8sand ears$ ItAs te astronomial e'ent not o& one li&etime, b8t o& a doen$ Notin) on tis sale as o8rred sine te in'ention o& te teles ope$ So in mid >8l 1994, in a bea8ti&8ll oordinated international sienti&i e&&ort, telesopes all o'er te Eart and in spae t8rned to(ards >8piter$ stronomers ad o'er a ear to prepare$ e traHetories o& te &ra)ments in teir orbits aro8nd >8piter (ere estimated$ It (as diso'ered tat te (o8ld all it >8piter$ reditions o& te timin) (ere re&ined$ !isappointin)l, te al8lations re'ealed tat all impats (o8ld o8r on te ni)t side o& >8piter, te side in'isible &rom te Eart =alto8) aessible to te %alileo and
Vo$ager spaera&t in te o8ter Solar Sstem<$ B8t, appil, all impats (o8ld o8r onl a &e( min8tes be&ore te >o'ian da(n, be&ore te impat site (o8ld be arried b >8piterAs rotation into te line o& si)t &rom Eart$ e appointed moment &or te impat o& te &irst piee, %ra)ment , ame and (ent$ ere (ere no reports &rom )ro8nd-based telesopes$ lanetar sientists stared (it inreasin) )loom
144
at a tele'ision monitor displain) te data transmitted to te Spae elesope Siene Instit8te in Baltimore &rom te 8bble Spae elesope$ ere (as notin) anomalo8s S8ttle astrona8ts took time o&& &rom te reprod8tion o& &r8it &lies, &is, and ne(ts to look at >8piter tro8) bino8lars$ e reported seein) notin)$ e impat o& te millenni8m (as be)innin) to look 'er m8 like a &ile$ en tere (as a report &rom a )ro8nd-based optial telesope in .a alma in te +anar Islands, &ollo(ed b anno8nements &rom a radiotelesope in >apan? &rom te E8ropean So8tern 2bser'ator in +ile? and &rom a ni'ersit o& +ia)o instr8ment in te &ri)id (astelands o& te So8t ole$ In Baltimore te o8n) sientists ro(din) aro8nd te # monitorGtemsel'es monitored b te ameras o& +NNGbe)an to see sometin), and in eCatl te ri)t plae on >8piter$ o8 o8ld (itness onsternation t8rn into p8lement, and ten eC8ltation$ e eered? te sreamed? te H8mped 8p and do(n$ Smiles &illed te room$ e broke o8t te ampa)ne$ ere (as a )ro8p o& o8n) merian sientistsGabo8t a tird o& tem, inl8din) te team leader, eidi ammel, (omenGand o8 o8ld ima)ine o8n)sters all o'er te (orld tinkin) tat it mi)t be &8n to be a sientist, tat tis mi)t be a )ood datime Hob, or e'en a means to spirit8al &8l&illment$ %or man o& te &ra)ments, obser'ers some(ere on Eart notied te &ireball rise so K8ikl and so i) tat it o8ld be seen e'en to8) te impat site belo( it (as still in >o'ian darkness$ l8mes asended and ten &lattened into panake-like &orms$ Spreadin) o8t &rom te point o& impat (e o8ld see so8nd and )ra'it (a'es, and a pat o& disoloration tat &or te lar)est &ra)ments beame as bi) as te Eart$ Slammin) into >8piter at 60 kilometers a seond =130,000 miles an o8r<, te lar)e &ra)ments on'erted teir kineti ener) partl into sok (a'es, partl into eat$ e temperat8re in te &ireball (as estimated at to8sands o& de)rees$ Some o& te &ireballs and pl8mes (ere &ar bri)ter tan all te rest o& >8piter p8t to)eter$ *at is te a8se o& te dark stains le&t a&ter te impatD It mi)t be st8&& &rom te deep lo8ds o& >8piter-&rom te re)ion to (i )ro8nd-based obser'ers annot ordinaril see-tat (elled 8p and spread o8t$ o(e'er, te &ra)ments do not seem to a'e penetrated to s8 depts$ 2r te mole8les responsible &or te stains mi)t a'e been in te ometar &ra)ments in te &irst plae$ *e kno( &rom te Vega 1 and 2 So'iet missions and te %io""o mission o& te E8ropean Spae )enGbot to alleAs +ometGtat omets ma be as m8 as a K8arter omposed o& ompleC or)ani mole8les$ e are te reason tat te n8le8s o& alleAs +omet is pit blak$ I& some o& te ometar or)anis s8r'i'ed te impat e'ents, te ma a'e been responsible &or te stain$ 2r, &inall, te stain ma be d8e to or)ani matter not deli'ered b te impatin) ometar &ra)ments, b8t sntesied b teir sok (a'es &rom te atmospere o& >8piter$ Impat o& te &ra)ments o& +omet Soemaker-.e' 9 (it >8piter (as (itnessed on se'en ontinents$ E'en amate8r astrono mers (it small telesopes o8ld see te pl8mes and te s8bseK8ent disoloration o& te >o'ian lo8ds$ >8st as sportin) e'ents are o'ered at all an)les b tele'ision ameras on te &ield and &rom a diri)ible i) o'eread, siC NS spaera&t deploed tro8)o8t te Solar Sstem, (it di&&erent obser'ational speialties, reorded tis 145
ne( (onderGte u;;le Spa7e /ele7ope, t e !n"erna"ional l"ra4iole" Explorer , and te
Ex"reme l"ra4iole" Explorer all in Eart orbit? lsses, takin) time o8t &rom it in'esti)ation o& te So8t ole o& te S8n? /alileo, on te (a to its o(n rende'o8s (it >8piter? and Vo$ager
2, &ar beond Nept8ne on its (a to te stars$ s te data are a8m8lated and analed, o8r kno(led)e o& omets, o& >8piter, and o& te 'iolent ollisions o& (orlds so8ld all be s8bstantiall impro'ed$ %or man sientistsGb8t espeiall &or +aroln and E8)ene Soemaker and !a'id .e'G tere (as sometin) poi)nant abo8t te ometar &ra)ments, one a&ter te oter, makin) teir deat pl8n)es into >8piter$ e ad li'ed (it tis omet, in a manner o& speakin), &or 16 monts, (ated it split, te piees, ensro8ded b lo8ds o& d8st, plain) ide-and-seek and spreadin) o8t in teir orbits$ In a limited (a, ea &ra)ment ad its o(n personalit$ No( teAre all )one, ablated into mole8les and atoms in te 8pper atmospere o& te Solar SstemAs lar)est planet$ In a (a, (e almost mo8rn tem$ B8t (eAre learnin) &rom teir &ier deats$ It is peraps some reass8rane to kno( tat tere are a 8ndred trillion more o& tem in te S8nAs 'ast treas8re-o8se o& (orlds$
THERE ARE ABOUT!%%
kno(n asteroids (ose pats take tem near te Eart$ e are alled,
appropriatel eno8), near-Eart asteroids$ eir detailed appearane =like tat o& teir mainbelt o8sins< immediatel implies tat te are te prod8ts o& a 'iolent ollisional istor$ an o& tem ma be te sards and remnants o& one-lar)er (orldlets$ *it a &e( eCeptions, te near-Eart asteroids are onl a &e( kilometers aross or smaller, and take one to a &e( ears to make a ir8it aro8nd te S8n$ bo8t "0 perent o& tem, sooner or later, are bo8nd to it te EartG(it de'astatin) onseK8enes$ =B8t in astronom, sooner or later an enompass billions o& ears$< +ieroAs ass8rane tat notin) o& ane or aard is to be &o8nd in an absol8tel ordered and re)8lar ea'en is a pro&o8nd mispereption$ E'en toda, as +omet Soemaker-.e' 9As eno8nter (it >8piter reminds 8s, tere is ro8tine interplanetar 'iolene, alto8) not on te sale tat marked te earl istor o& te Solar Sstem$ .ike main-belt asteroids, man near-Eart asteroids are rok$ &e( are mainl metal, and it as been s8))ested tat enormo8s re(ards mi)t attend mo'in) s8 an asteroid into orbit aro8nd te Eart, and ten sstematiall minin) itGa mo8ntain o& i)-)rade ore a &e( 8ndred miles o'eread$ e 'al8e o& platin8m-)ro8p metals alone in a sin)le s8 (orld as been estimated as man trillions o& dollarsGalto8) te 8nit prie (o8ld pl8mmet speta8larl i& s8 materials beame (idel a'ailable$ etods o& eCtratin) metals and minerals &rom appropriate asteroids are bein) st8died, &or eCample b >on .e(is, a planetar sientist at te ni'ersit o& riona$ Some near-Eart asteroids are ri in or)ani matter, apparentl preser'ed &rom te 'er earliest Solar Sstem$ Some a'e been &o8nd, b Ste'en 2stro o& te >et rop8lsion .aborator, to be do8ble, t(o bodies in ontat$ eraps a lar)er (orld as broken in t(o as it passed tro8) te stron) )ra'itational tides o& a planet like >8piter? more interestin) is te possibilit tat t(o 146
(orlds on similar orbits made a )entle o'ertakin) ollision and st8k$ is proess ma a'e been ke to te b8ildin) o& planets and te Eart$ t least one asteroid =Ida, as 'ie(ed b
%alileo< as its o(n small moon$ *e mi)t )8ess tat t(o asteroids in ontat and t(o asteroids orbitin) one anoter a'e related ori)ins$ Sometimes, (e ear abo8t an asteroid makin) a near miss$ =* do (e all it a near missD near it is (at (e reall mean$< B8t ten (e read a little more are&8ll, and it t8rns o8t tat its losest approa to te Eart (as se'eral 8ndreds o& to8sands or millions o& kilometers$ at doesnAt o8ntGtatAs too &ar a(a, &arter e'en tan te oon$ I& (e ad an in'entor o& all te near-Eart asteroids, inl8din) tose onsiderabl smaller tan a kilometer aross, (e o8ld proHet teir orbits into te &8t8re and predit (i ones are potentiall dan)ero8s$ ere are an estimated ",000 o& tem bi))er tan a kilometer aross, o& (i (e a'e at8all obser'ed onl a &e( perent$ ere are mabe "00,000 bi))er tan 100 meters in diameter$ e near-Eart asteroid s a'e e'oati'e mtolo)ial names: 2rpe8s, ator, Iar8s, donis, pollo, +erber8s, 8&8, mor, antal8s, ten, idas, a-Salom, aeton, o8tatis, T8etaloatl$ ere are a &e( o& speial eCplorator potentialG&or eCample, Nere8s$ In )eneral, itAs m8 easier to )et onto and o&& o& near-Eart asteroids tan te oon$ Nere8s, a tin (orld abo8t a kilometer aross, is one o& te easiest$ 1 It (o8ld be real eCploration o& a tr8l ne( (orld$ Some 8mans =all &rom te &ormer So'iet nion< a'e alread been in spae &or periods lon)er tan te entire ro8ndtrip time to Nere8s$ e roket tenolo) to )et tere alread eCists$ ItAs a m8 smaller step tan )oin) to ars or e'en, in se'eral respets, tan ret8rnin) to te oon$ I& sometin) (ent (ron), to8), (e (o8ld be 8nable to r8n ome to sa&et in onl a &e( das$ In tis respet, its le'el o& di&&i8lt lies some(ere bet(een a 'oa)e to ars and one to te oon$ 2& man possible &8t8re missions to Nere8s, tereAs one tat takes 10 monts to )et tere &rom Eart, spends 30 das tere, and ten reK8ires onl 3 (eeks to ret8rn to ome$ *e o8ld 'isit Nere8s (it robots, orGi& (eAre 8p to itG(it 8mans$ *e o8ld eCamine tis little (orldAs sape, onstit8tion, interior, past istor, or)ani emistr, osmi e'ol8tion, and possible tie to omets$ *e o8ld brin) samples bak &or eCamination at leis8re in Eartbo8nd laboratories$ *e o8ld in'esti)ate (eter tere reall are ommeriall 'al8able reso8resG metals or mineralsGtere$ I& (e are e'er )oin) to send 8mans to ars, near-Eart asteroids pro'ide a on'enient and appropriate intermediate )oalGto test o8t te eK8ipment and eCplorator protools (ile st8din) an almost (oll 8nkno(n little (orld$ ereAs a (a to )et o8r &eet (et a)ain (en (eAre read to reenter te osmi oean$
1
steroid 1991>* as an orbit 'er m8 like te EartAs and is e'en easier to )et to tan 4660 Nere8s$ B8t its orbit seems too
Sa"urn V Apollo oon roket$ similar to te EartAs &or it to be a nat8ral obHet$ eraps itAs some lost 8pper sta)e o& te
147
C
H
A
P
T
E
R
18
E S 2% +IN QIRtAs too late to make an impro'ements no($ e 8ni'erse is &inised? te opestone is on, and te ips (ere arted o&& a million ears a)o$ GEN E.#I..E, MO>, .!#D, +E " =1;51<
14;
Camarina (as a it in so8tern Siil, &o8nded b olonists &rom Sra8se in 59; B$+$ )eneration or t(o later, it (as treatened b a pestileneG&esterin), some said, in te adHaent mars$ =*ile te )erm teor o& disease (as ertainl not (idel aepted in te anient (orld, tere (ere ints-&or eCample, ar8s #arro in te &irst ent8r B$ +$ ad'ised eCpliitl a)ainst b8ildin) ities near s(amps bea8se tere are bred ertain min8te reat8res (i annot be seen b te ees, (i &loat in te air and enter te bod tro8) te mo8t and nose and tere a8se serio8s disease$< e dan)er to +amarina (as )reat$ lans (ere dra(n to drain te mars$ *en te orale (as ons8lted, to8), it &orbade s8 a o8rse o& ation, o8nselin) patiene instead$ B8t li'es (ere at stake, te orale (as i)no red, and te mars (as drain ed$ e pestilene (as promptl alted$ oo late, it (as reo)nied tat te mars ad proteted te it &rom its enemiesGamon) (om tere ad no( to be o8nted teir o8sins te Sra8sans$ s in meria ",300 ears later, te olonists ad K8arreled (it te moter o8ntr$ In 55" B$+$, a Sra8san &ore rossed o'er te dr land (ere te mars ad been, sla8)tered e'er man, (oman, and ild, and raed te it$ e mars o& +amarina beame pro'erbial &or eliminatin) a dan)er in s8 a (a as to 8ser in anoter, m8 (orse$
THE CRETACEOUS-TERTIARY COLLISION =or
ollisionsGtere ma a'e been more tan one< ill8minates te peril &rom asteroids and omets$ In seK8ene, a (orld-immolatin) &ire b8rned 'e)etation to a risp all o'er te planet? a stratosperi d8st lo8d so darkened te sk tat s8r'i'in) plants ad tro8ble makin) a li'in) &rom potosntesis? tere (ere (orld(ide &reein) temperat8res, torrential rains o& a8sti aids, massi'e depletion o& te oone laer, and, to top it o&&, a&ter te Eart ealed itsel& &rom tese assa8lts, a prolon)ed )reeno8se (armin) =bea8se te main impat seems to a'e 'olatilied a deep laer o& sedimentar arbonates, po8rin) 8)e amo8nts o& arbon dioCide into te air<$ It (as not a sin)le atastrope, b8t a parade o& tem, a onatenation o& terrors$ 2r)anisms (eakened b one disaster (ere &inised o&& b te neCt$ It is K8ite 8nertain (eter o8r i'iliation (o8ld s8r'i'e e'en a onsiderabl less ener)eti ollision$ Sine tere are man more small asteroids tan lar)e ones, r8n-o&-te-mill ollisions (it te Eart (ill be made b te little )8s$ B8t te lon)er o8Are prepared to (ait, te more de'astatin) te impat o8 an eCpet$ 2n a'era)e, one e'er &e( 8ndred ears te Eart is it b an obHet abo8t 70 meters in diameter? te res8ltin) ener) released is eK8i'alent to te lar)est n8lear (eapons eCplosion e'er detonated$ E'er 10,000 ears, (eAre it b a "00-meter obHet tat mi)t ind8e serio8s re)ional limati e&&ets$ E'er million ears, an impat b a bod o'er " kilometers in diameter o8rs, eK8i'alent to nearl a million me)atons o& NGan eCplosion tat (o8ld (ork a )lobal atastrope, killin) =8nless 8npreedented prea8tions (ere taken< a si)ni&iant &ration o& te 8man speies$ million me)atons o& N is 100 times te eCplosi'e ield o& all te n8lear (eapons on te planet, i& sim8ltaneo8sl blo(n 8p$ !(ar&in) e'en tis, in a 8ndred million ears or so, o8 an bet on sometin) like te +retaeo8s-
149
ertiar e'ent, te impat o& a (orld 10 kilometers aross or bi))er$ e destr8ti'e ener) latent in a lar)e near-Eart asteroid d(ar&s antin) else te 8man speies an )et its ands on$ s &irst so(n b te merian planetar sientist +ristoper +ba and is ollea)8es, little asteroids or omets, a &e( tens o& meters aross, break and b8rn 8p on enterin) o8r atmospere$ e arri'e omparati'el o&ten b8t do no si)ni&iant arm$ Some idea o& o( &reK8entl te enter te EartAs atmospere as been re'ealed b delassi&ied !epartment o& !e&ense data obtained &rom speial satellites monitorin) te Eart &or landestine n8lear eCplosions$ ere seem to a'e been 8ndreds o& small (orldlets =and at least one lar)er bod< impatin) in te last "0 ears$ e did no arm$ B8t, (e need to be 'er s8re (e an distin)8is a small ollidin) omet or asteroid &rom an atmosperi n8lear eCplosion$ +i'iliation-treatenin) impats reK8ire bodies se'eral 8ndred meters aross, or more$ = meter is abo8t a ard? 100 meters is ro8)l te len)t o& a &ootball &ield$< e arri'e sometin) like one e'er "00,000 ears$ 28r i'iliation is onl abo8t 10,000 ears old, so (e so8ld a'e no instit8tional memor o& te last s8 impat$ Nor do (e$ +omet Soemaker-.e' 9, in its s8ession o& &ier eCplosions on >8piter in >8l 1994, reminds 8s tat s8 impats reall do o8r in o8r timeGand tat te impat o& a bod a &e( kilometers aross an spread debris o'er an area as bi) as te Eart$ It (as a kind o& portent$ In te 'er (eek o& te Soemaker-.e' impat, te Siene and Spae +ommittee o& te $S$ o8se o& epresentati'es dra&ted le)islation tat reK8ires NS in oordination (it te !epartment o& !e&ense and te spae a)enies o& oter o8ntries to identi& and determine te orbital arateristis o& all Eart-approain) omets and asteroids tat are )reater tan 1 kilometer in diameter$ e (ork is to be ompleted b te ear "005$ S8 a sear pro)ram ad been ad'oated b man planetar sientists$ B8t it took te deat troes o& a omet to mo'e it to(ard pratial implementation$ Spread o8t o'er te (aitin) time, te dan)ers o& asteroid ollision do not seem 'er (orrisome$ B8t i& a bi) impat appens, it (o8ld be an 8npreedented 8man atastrope$ ereAs sometin) like one ane in t(o to8sand tat s8 a ollision (ill appen in te li&etime o& a ne(born bab$ ost o& 8s (o8ld not &l in an airplane i& te ane o& rasin) (ere one in t(o to8sand$ =In &at &or ommerial &li)ts te ane is one in t(o million$ E'en so, man people onsider tis lar)e eno8) to (orr abo8t, or e'en to take o8t ins8rane &or$< *en o8r li'es are at stake, (e o&ten an)e o8r bea'ior to arran)e more &a'orable odds$ ose (o donAt tend to be no lon)er (it 8s$ eraps (e so8ld pratie )ettin) to tese (orldlets and di'ertin) teir orbits, so8ld te o8r o& need e'er arise$ el'ille not(itstandin), some o& te ips o& reation are still le&t, and impro'ements e'identl need to be made$ lon) parallel and onl (eakl interatin) traks, te planetar siene omm8nit and te $S$ and 8ssian n8lear (eapons laboratories, a(are o& te &ore)oin) senarios, a'e been p8rs8in) tese K8estions: o( to monitor all siable nearEart interplanetar obHets, o( to araterie teir psial and emial nat8re, o( to predit (i ones ma be on a &8t8re ollision traHetor (it Eart, and, &inall, o( to pre'ent a ollision &rom appenin)$
150
e 8ssian spae&li)t pioneer onstantin siolko'sk ar)8ed a ent8r a)o tat tere m8st be bodies intermediate ill sie bet(een te obser'ed lar)e asteroids and tose asteroidal &ra)ments, te meteorites, tat oasionall &all to Eart$ e (rote abo8t li'in) on small asteroids in interplanetar spae$ e did not a'e militar appliations in mind$ In te earl 19;0s, to8), some in te $S$ (eapons establisment ar)8ed tat te So'iets mi)t 8se nearEart asteroids as &irst-strike (eapons? te alle)ed plan (as alled I'anAs ammer$ +o8ntermeas8res (ere needed$ B8t, at te same time, it (as s8))ested, mabe it (asnAt a bad idea &or te nited States to learn o( to 8se small (orlds as (eapons o& its o(n$ e !e&ense !epartmentAs Ballisti issile !e&ense 2r)aniation, te s8essor to te Star *ars o&&ie o& te 19;0s, la8ned an inno'ati'e spaera&t alled #lemen"ine to orbit te oon and &l b te near-Eart asteroid /eo)rapos$ =&ter ompletin) a remarkable reonnaissane o& te oon in a 1994, te spaera&t &ailed be&ore it o8ld rea /eo)rapos$< In priniple, o8 o8ld 8se bi) roket en)ines, or proHetile impat, or eK8ip tile asteroid (it )iant re&leti'e panels and so'e it (it s8nli)t or po(er&8l Eart-based lasers$ B8t (it tenolo) tat eCists ri)t no(, tere are onl t(o (as$ %irst, one or more i)-ield n8lear (eapons mi)t blast te asteroid or omet into &ra)ments tat (o8ld disinte)rate and atomie on enterin) te EartAs atmospere$ I& te o&&endin) (orldlet is onl (eakl eld to)eter, peraps onl 8ndreds o& me)atons (o8ld s8&&ie$ Sine tere is no teoretial 8pper limit to te eCplosi'e ield o& a termon8lear (eapon, tere seem to be tose in te (eapons laboratories (o onsider makin) bi))er bombs not onl as a stirrin) all en)e, b8t also as a (a to m8te pesk en'ironmentalists b se8rin) a seat &or n8lear (eapons on te sa'e-te-Eart band(a)on$ noter approa 8nder more serio8s dis8ssion is less dramati b8t still an e&&eti'e (a o& maintainin) te (eapons establismentGa plan to alter te orbit o& an errant (orldlet b eCplodin) n8lear (eapons nearb$ e eCplosions =)enerall near te asteroidAs losest point to te S8n< are arran)ed to de&let it a(a &rom te Eart$ 1 &l8rr o& lo(-ield n8lear (eapons, ea )i'in) a little p8s in te desired diretion, is eno8) to de&let a medi8m-sied asteroid (it onl a &e( (eeksA (arnin)$ e metod also o&&ers, it is oped, a (a to deal (it a s8ddenl deteted lon)-period omet on imminent ollision traHetor (it te Eart: e omet (o8ld be interepted (it a small asteroid$ =Needless to sa, tis )ame o& elestial billiards is e'en more di&&i8lt and 8nertainGand tere&ore e'en less pratial in te near &8t8reGtan te erdin) o& an asteroid on a kno(n, (ell-bea'ed orbit (it monts or ears at o8r disposal$< *e donAt kno( (at a stando&& n8lear eCplosion (o8ld do to an asteroid$ e ans(er ma 'ar &rom asteroid to asteroid$ Some small (orlds mi)t be stron)l eld to)eter? oters mi)t be little more tan sel&-)ra'itatin) )ra'el eaps$ I& an eCplosion breaks, letAs sa, a 10kilometer asteroid 8p into 8ndreds o& 1-kilometer &ra)ments, te likeliood tat at least one 1
e 28ter Spae reat, adered to bot b te nited States and 8ssia, proibits (eapons o& mass destr8tion in o8ter spae$ steroid de&letion tenolo) onstit8tes H8st s8 a (eaponGindeed, te most po(er&8l (eapon o& mass destr8tion e'er de'ised$ ose interested in de'elopin) asteroid de&letion tenolo) (ill (ant to a'e te treat re'ised$ B8t e'en (it no re'ision, (ere a lar)e asteroid to be diso'ered on impat traHetor (it te Eart, pres8mabl no oneAs and (o8ld be staed b te nieties o& international diploma$ ere is a dan)er, to8), tat relaCin) proibitions on s8 (eapons in spae mi)t make 8s less attenti'e $bo8t te positionin) o& (areads &or o&&ensi'e p8rposes in spae$
151
o& tem impats te Eart is probabl inreased, and te apoalpti arater o& te onseK8enes ma not be m8 red8ed$ 2n te oter and, i& te eCplosion disr8pts te asteroid into a s(arm o& obHets a 8ndred meters in diameter or smaller, all o& tem mi)t ablate a(a like )iant meteors on enterin) te EartAs atmospere$ In tis ase little impat dama)e (o8ld be a8sed$ E'en i& te asteroid (ere (oll p8l'eried into &ine po(der, to8), te res8ltin) i)altit8de d8st laer mi)t be so opaK8e as to blok te s8nli)t and an)e te limate$ *e do not et kno($
'ision o& doens or 8ndreds o& n8lear-armed missiles on read standb to deal
(it treatenin) asteroids or omets as been o&&ered$ o(e'er premat8re in tis parti8lar appliation, it seems 'er &amiliar? onl te enem as been an)ed$ It also seems 'er dan)ero8s$ e problem, Ste'en 2stro o& >. and I a'e s8))ested, is tat i& o8 an reliabl de&let a treatenin) (orldlet so it does not ollide (it te Eart, o8 an also reliabl de&let a armless (orldlet so it oe ollide (it te Eart$ S8ppose o8 ad a &8ll in'entor, (it orbits, o& te estimated 300,000 near-Eart asteroids lar)er tan 100 metersGea o& tem lar)e eno8), on impatin) te Eart, to a'e serio8s onseK8enes$ en, it t8rns o8t, o8 also a'e a list o& 8)e n8mbers o& ino&&ensi'e asteroids (ose orbits o8ld be altered (it n8lear (areads so te K8ikl ollide (it te Eart$ S8ppose (e restrit o8r attention to te ",000 or so near-Eart asteroids tat are a kilometer aross or bi))erGtat is, te ones most likel to a8se a )lobal atastrope$ oda, (it onl abo8t 100 o& tese obHets atalo)8ed, it (o8ld take abo8t a ent8r to at one (en itAs easil de&letable to Eart and alter its orbit$ *e tink (eA'e &o8nd one, an as-et-8nnamed 1 asteroid so &ar denoted onl as 19912$ In "070, tis (orld, abo8t 1 kilometer in diameter, (ill ome (itin 4$5 million kilometers o& te EartAs orbitGonl &i&teen times te distane to te oon$ o de&let 19912 so it its te Eart, onl abo8t 60 me)atons o& N eK8i'alent needs to be eCploded in te ri)t (aGte eK8i'alent o& a small n8mber o& 8rrentl a'ailable n8lear (areads$ No( ima)ine a time, a &e( deades ene, (en all s8 near-Eart asteroids are in'entoried and teir orbits ompiled$ en, as lan arris o& >., /re) +ana'an o& te .os lamos National .aborator, 2stro, and I a'e so(n, it mi)t take onl a ear to selet a s8itable obHet, alter its orbit, and send it rasin) into te Eart (it atalsmi e&&et$ e tenolo) reK8iredGlar)e optial telesopes, sensiti'e detetors, roket prop8lsion sstems able to li&t a &e( tons o& paload and make preise rende'o8s in nearb spae, and termon8lear (eaponsGall eCist toda$ Impro'ements in all b8t peraps te last an be on&identl eCpeted$ I& (eAre not are&8l, man nations ma a'e tese apabilities in te neCt &e( deades$ *at kind o& (orld (ill (e ten a'e madeD
1
*at so8ld (e all tis (orldD Namin) it a&ter te /reek %ates or %8ries or Nemesis seems inappropriate, bea8se (eter it misses or its te Eart is entirel in o8r ands$ I& (e lea'e it alone, it misses$ I& (e p8s it le'erl and preisel, it its$ abe (e so8ld all it Ei)t Ball$
15"
*e a'e a tenden to minimie te dan)ers o& ne( tenolo)ies$ ear be&ore te +ernobl disaster, a So'iet n8lear po(er ind8str dep8t minister (as asked abo8t te sa&et o& So'iet reators, and ose +ernobl as a parti8larl sa&e site$ e a'era)e (aitin) time to disaster, e on&identl estimated, (as a 8ndred to8sand ears$ .ess tan a ear later $ $ $ de'astation$ Similar reass8ranes (ere pro'ided b NS ontrators te ear be&ore te
#allenger disaster: o8 (o8ld a'e to (ait ten to8sand ears, te estimated, &or a atastropi &ail8re o& te s8ttle$ 2ne ear later $ $ $ eartbreak$ +loro&l8oroarbons =+%+s< (ere de'eloped spei&iall as a ompletel sa&e re&ri)erantG to replae ammonia and oter re&ri)erants tat, on leakin) o8t, ad a8sed illness and some deats$ +emiall inert, nontoCi =in ordinar onentrations<, odorless, tasteless, nonaller)eni, non&lammable, +%+s represent a brilliant tenial sol8tion to a (ell-de&ined pratial problem$ e &o8nd 8ses in man oter ind8stries besides re&ri)eration and air onditionin)$ B8t, as I desribed abo'e, te emists (o de'eloped +%+s o'erlooked one essential &atGtat te mole8lesA 'er inertness )8arantees tat te are ir8lated to stratosperi altit8des and tere raked open b s8nli)t, releasin) lorine atoms (i ten attak te proteti'e oone laer$ !8e to te (ork o& a &e( sientists, te dan)ers ma a'e been reo)nied and a'erted in time$ *e 8mans a'e no( almost stopped prod8in) +%+s$ *e (onAt at8all kno( i& (eA'e a'oided real arm &or abo8t a ent8r? tatAs o( lon) it takes &or all te +%+ dama)e to be ompleted$ .ike te anient +amarinans, (e make mistakes$ 1 Not onl do (e o&ten i)nore te (arnin)s o& te 2rales? arateristiall (e do not e'en ons8lt tem$ e notion o& mo'in) asteroids into Eart orbit as pro'ed attrati'e to some spae sientists and lon)-ran)e planners$ e &oresee minin) te minerals and preio8s metals o& tese (orlds or pro'idin) reso8res &or te onstr8tion o& spae in&rastr8t8re (ito8t a'in) to &i)t te EartAs )ra'it to )et tem 8p tere$ rtiles a'e been p8blised on o( to aomplis tis end and (at te bene&its (ill be$ In modern dis8ssions, te asteroid is inserted into orbit aro8nd te Eart b &irst makin) it pass tro8) and be braked b te EartAs atmospere, a mane8'er (it 'er little mar)in &or error$ %or te near &8t8re (e an, I tink, reo)nie tis (ole endea'or as 8n8s8all dan)ero8s and &oolard, espeiall &or metal (orldlets lar)er tan tens o& meters aross$ is is te one ati'it (ere errors in na'i)ation or prop8lsion or mission desi)n an a'e te most s(eepin) and atastropi onseK8enes$ e &ore)oin) are eCamples o& inad'ertene$ B8t tereAs anoter kind o& peril: *e are sometimes told tat tis or tat in'ention (o8ld o& o8rse not be mis8sed$ No sane person (o8ld be so rekless$ is is te onl a madman ar)8ment$ *ene'er I ear it =and itAs o&ten trotted o8t in s8 debates<, I remind msel& tat madmen reall eCist$ Sometimes te aie'e te i)est le'els o& politial po(er in modern ind8strial nations$ is is te ent8r o& itler and Stalin, trants (o posed te )ra'est dan)ers not H8st to te rest o& te 8man &amil, b8t to teir o(n people as (ell$ In te (inter and sprin) o& 1945, itler ordered /erman to be destroedG e'en (at te people need &or elementar s8r'i'alGbea8se te s8r'i'in) /ermans ad 1
ere is o& o8rse a (ide ran)e o& oter problems bro8)t on b te de'astatin)l po(er&8l tenolo) (eA'e reentl in'ented$ B8t in most ases teAre not +amarinan disasters-damned i& o8 do and damned i& o8 donAt$ Instead teAre dilemmas o& (isdom or timin)-&or eCample, te (ron) re&ri)erant or re&ri)eration psis o8t o& man possible alternati'es$
153
betraed im, and at an rate (ere in&erior to tose (o ad alread died$ I& itler ad ad n8lear (eapons, te treat o& a o8nterstrike b llied n8lear (eapons, ad tere been an, is 8nlikel to a'e diss8aded im$ It mi)t a'e eno8ra)ed im$ +an (e 8mans be tr8sted (it i'iliation-treatenin) tenolo)iesD I& te ane is almost one in a to8sand tat m8 o& te 8man pop8lation (ill be killed b an impat in te neCt ent8r, isnAt it more likel tat asteroid de&letion tenolo) (ill )et into te (ron) ands in anoter ent8rGsome misantropi soiopat like a itler or a Stalin ea)er to kill e'erbod, a me)alomania l8stin) a&ter )reatness and )lor, a 'itim o& etni 'iolene bent on re'en)e, someone in te )rip o& 8n8s8all se'ere testosterone poisonin), some reli)io8s &anati astenin) te !a o& H8d)ment, or H8st teniians inompetent or ins8&&iientl 'i)ilant in andlin) te ontrols and sa&e)8ardsD S8 people eCist$ e risks seem &ar (orse tan te bene&its, te 8re (orse tan te disease$ e lo8d o& near-Eart asteroids tro8) (i te Eart plo(s ma onstit8te a modern +amarine mars$ ItAs eas to tink tat all o& tis m8st be 'er 8nlikel, mere anCio8s &antas$ S8rel sober eads (o8ld pre'ail$ ink o& o( man people (o8ld be in'ol'ed in preparin) and la8nin) (areads, in spae na'i)ation, in detonatin) (areads, in ekin) (at orbital pert8rbation ea n8lear eCplosion as made, in erdin) te asteroid so it is on an impat traHetor (it Eart, and so on$ IsnAt it note(ort tat alto8) itler )a'e orders &or te retreatin) Nai troops to b8rn aris and to la (aste to /erman itsel&, is orders (ere not arried o8tD S8rel someone essential to te s8ess o& te de&letion mission (ill reo)nie te dan)er$ E'en ass8ranes tat te proHet is desi)ned to destro some 'ile enem nation (o8ld probabl be disbelie'ed, bea8se te e&&ets o& ollision are planet-(ide =and an(a itAs 'er ard to make s8re o8r asteroid eCa'ates its monster rater in a parti8larl deser'in) nation<$ B8t no( ima)ine a totalitarian state, not o'err8n b enem troops, b8t one tri'in) and sel&on&ident$ Ima)ine a tradition in (i orders are obeed (ito8t K8estion$ Ima)ine tat tose in'ol'ed in te operation are s8pplied a o'er stor: e asteroid is abo8t to impat te Eart, and it is teir Hob to de&let itGb8t in order not to (orr people needlessl, te operation m8st be per&ormed in seret$ In a militar settin) (it a ommand ierar &irml in plae, ompartmentaliation o& kno(led)e, )eneral sere, and a o'er stor, an (e be on&ident tat e'en apoalpti orders (o8ld be disobeedD re (e reall s8re tat in te neCt deades and ent8ries and millennia, notin) like tis mi)t appenD o( s8re are (eD ItAs no 8se sain) tat all tenolo)ies an be 8sed &or )ood or &or ill$ at is ertainl tr8e, b8t (en te ill aie'es a s8&&iientl apoalpti sale, (e ma a'e to set limits on (i tenolo)ies ma be de'eloped$ =In a (a (e do tis all te time, bea8se (e anAt a&&ord to de'elop all tenolo)ies$ Some are &a'ored and some are not$< 2r onstraints ma a'e to be le'ied b te omm8nit o& nations on madmen and a8tars and &anatiism$ rakin) asteroids and omets is pr8dent, itAs )ood siene, and it doesnAt ost m8$ B8t, kno(in) o8r (eaknesses, ( (o8ld (e e'en onsider no( de'elopin) te tenolo) to de&let small (orldsD %or sa&et, sall (e ima)ine tis tenolo) in te ands o& man nations, ea pro'idin) eks and balanes a)ainst mis8se b anoterD is is notin) like te old n8lear balane o& terror$ It ardl inibits some madman intent on )lobal atastrope to kno( tat i& e 154
does not 8rr, a ri'al ma beat im to it$ o( on&ident an (e be tat te omm8nit o& nations (ill be able to detet a le'erl desi)ned, landestine asteroid de&letion in time to do sometin) abo8t itD I& s8 a tenolo) (ere de'eloped, an an international sa&e)8ards be en'isioned tat a'e a reliabilit ommens8rate (it te riskD E'en i& (e restrit o8rsel'es merel to s8r'eillane, tereAs a risk$ Ima)ine tat in a )eneration (e araterie te orbits o& 30,000 obHets o& 100-meter diameter or more, and tat tis in&ormation is p8bliied, as o& o8rse it so8ld be$ aps (ill be p8blised so(in) nearEart spae blak (it te orbits o& asteroids and omets, 30,000 s(ords o& !amoles an)in) o'er o8r eads-ten times more tan te n8mber o& stars 'isible to te naked ee 8nder onditions o& optim8m atmosperi larit$ 8bli anCiet mi)t be m8 )reater in s8 a time o& kno(led)e tan in o8r 8rrent a)e o& i)norane$ ere mi)t be irresistible p8bli press8re to de'elop means to miti)ate e'en noneCistent treats, (i (o8ld ten &eed te dan)er tat de&letion tenolo) (o8ld be mis8sed$ %or tis reason, asteroid diso'er and s8r'eillane ma not be a mere ne8tral tool o& &8t8re poli, b8t rater a kind o& boob trap$ o me, te onl &oreseeable sol8tion is a ombination o& a8rate orbit estimation, realisti treat assessment, and e&&eti'e p8bli ed8ationGso tat in demoraies at least, te itiens an make teir o(n, in&ormed deisions$ is is a Hob &or NS$ Near-Eart asteroids, and means o& alterin) teir orbits, are bein) looked at serio8sl$ ere is some si)n tat o&&iia ls in te !epartment o& !e&ense and te (eapons labora tories are be)innin) to 8nderstand tat tere ma be real dan)ers in plannin) to p8s asteroids aro8nd$ +i'ilian and militar sientists a'e met to dis8ss te s8bHet$ 2n &irst earin) abo8t te asteroid aard, man people tink o& it as a kind o& +iken .ittle &able? /oose-.8, ne(l arri'ed and in )reat eCitement, is omm8niatin) te 8r)ent ne(s tat te sk is &allin)$ e tenden to dismiss te prospet o& an atastrope tat (e a'e not personall (itnessed is in te lon) r8n 'er &oolis$ B8t in tis ase it ma be an all o& pr8dene$
MEANWHILE WE MUST STILL FACEte
de&letion dilemma$ I& (e de'elop and deplo tis
tenolo), it ma do 8s in$ I& (e donAt, some asteroid or omet ma do 8s in$ e resol8tion o& te dilemma in)es, I tink, on te &at tat te likel timesales o& te t(o dan)ers are 'er di&&erentGsort &or te &ormer, lon) &or te latter$ I like to tink tat o8r &8t8re in'ol'ement (it near-Eart asteroids (ill )o sometin) like tis: %rom )ro8nd-based obser'atories, (e diso'er all te bi) ones, plot and monitor teir orbits, determine rotation rates and ompositions$ Sientists are dili)ent in eCplainin) te dan)ers Gneiter eCa))eratin) nor m8tin) te prospets$ *e send roboti spaera&t to &l b a &e( seleted bodies, orbit tem, land on tem, and ret8rn s8r&ae samples to laboratories on Eart$ E'ent8all (e send 8mans$ =Bea8se o& te lo( )ra'ities, te (ill be able to make standin) broad H8mps o& ten kilometers or more into te sk, and lob a baseball into orbit aro8nd te asteroid$< %8ll a(are o& te dan)ers, (e make no attempts to alter traHetories 8ntil te potential &or mis8se o& (orld-alterin) tenolo)ies is m8 less$ at mi)t take a (ile$
155
I& (eAre too K8ik in de'elopin) te tenolo) to mo'e (orlds aro8nd, (e ma destro o8rsel'es? i& (eAre too slo(, (e (ill s8rel destro o8rsel'es$ e reliabilit o& (orld politial or)aniations and te on&idene te inspire (ill a'e to make si)ni&iant strides be&ore te an be tr8sted to deal (it a problem o& tis serio8sness$ t te same time, tere seems to be no aeptable national sol8tion$ *o (o8ld &eel om&ortable (it te means o& (orld destr8tion in te ands o& some dediated =or e'en potential< enem nation, (eter or not o8r nation ad omparable po(ersD e eCistene o& interplanetar ollision aards, (en (idel 8nderstood, (orks to brin) o8r speies to)eter$ *en &ain) a ommon dan)er, (e 8mans a'e sometimes reaed ei)ts (idel to8)t impossible? (e a'e set aside o8r di&&erenesGat least 8ntil te dan)er passed$ B8t "i dan)er ne'er passes$ e asteroids, )ra'itationall 8rnin), are slo(l alterin) teir orbits? (ito8t (arnin), ne( omets ome areenin) to(ard 8s &rom te transpl8tonian darkness$ ere (ill al(as be a need to deal (it tem in a (a tat does not endan)er 8s$ B posin) t(o di&&erent lasses o& perilGone nat8ral, te oter 8man-madeGte small near-Eart (orlds pro'ide a ne( and potent moti'ation to reate e&&eti'e transnational instit8tions and to 8ni& te 8man speies$ ItAs ard to see an satis&ator alternati'e$ In o8r 8s8al Hitter, t(o-steps-&or(ard-one-step-bak mode, *e are mo'in) to(ard 8ni&iation an(a$ ere are po(er&8l in&l8enes deri'in) &rom transportation and omm8niations tenolo)ies, te interdependent (orld eonom, and te )lobal en'ironmental risis$ e impat aard merel astens te pae$ E'ent8all, a8tio8sl, sr8p8lo8sl are&8l to attempt notin) (it asteroids tat o8ld inad'ertentl a8se a atastrope on Eart, I ima)ine (e (ill be)in to learn o( to an)e te orbits o& little nonmetalli (orlds, smaller tan 100 meters aross$ *e be)in (it smaller eCplosions and slo(l (ork o8r (a 8p$ *e )ain eCperiene in an)in) te orbits o& 'ario8s asteroids and omets o& di&&erent ompositions and stren)ts$ *e tr to determine (i ones an be p8sed aro8nd and (i annot$ B te t(ent-seond ent8r, peraps, (e mo'e small (orlds aro8nd te Solar Sstem, 8sin) =see neCt apter< not n8lear eCplosions b8t n8lear &8sion en)ines or teir eK8i'alents$ *e insert small asteroids made o& preio8s and ind8strial metals into Eart orbit$ /rad8all de'elop a de&ensi'e tenolo) to de&let a lar)e asteroid or omet tat mi)t in te &oreseeable &8t8re it te Eart, (ile, (it meti8lo8s are, (e b8ild laers o& sa&e)8ards a)ainst mis8se$ Sine te dan)er o& mis8sin) de&letion tenolo) seems so m8 )reater tan te dan)er o& an imminent impat, (e an a&&ord to (ait, take prea8tions, reb8ild politial instit8tionsG&or deades ertainl, probabl ent8ries$ I& (e pla o8r ards ri)t and are not 8nl8k, (e an pae (at (e do 8p tere b (at pro)ress (eAre makin) do(n ere$ e t(o are in an ase deepl onneted$ e asteroid aard &ores o8r and$ E'ent8all, (e m8st establis a &ormidable 8man presene tro8)o8t te inner Solar Sstem$ 2n an iss8e o& tis importane I do not tink (e (ill be ontent (it p8rel roboti means o& miti)ation$ o do so sa&el (e m8st make an)es in o8r politial and international sstems$ *ile m8 abo8t o8r &8t8re is lo8d, tis onl8sion seems a little more rob8st, and independent o& te 'a)aries o& 8man instit8tions$ 156
In te lon) term, e'en i& (e (ere not te desendants o& pro&essional (anderers, e'en i& (e (ere not inspired b eCplorator passions, some o& 8s (o8ld still a'e to lea'e te EartG simpl to ens8re te s8r'i'al o& all o& 8s$ nd one (eAre o8t tere, (eAll need bases, in&rastr8t8res$ It (o8ld not be 'er lon) be&ore some o& 8s (ere li'in) in arti&iial abitats and on oter (orlds$ is is te &irst o& t(o m8ssin) ar)8ments, omitted in o8r dis8ssion o& missions to ars, &or a permanent 8man presene in spae$ OTHER PLANETARY SYSTEMSm8st
&ae teir o(n impat aardsGbea8se small primordial
(orlds, o& (i asteroids and omets are remnants, are te st8&& o8t o& (i planets &orm tere as (ell$ &ter te planets are made, man o& tese planetesimals are le&t o'er$ e a'era)e time bet(een i'iliation-treatenin) impats on Eart is peraps "00,000 ears, t(ent times te a)e o& o8r i'iliation$ #er di&&erent (aitin) times ma pertain to eCtraterrestrial i'iliations, i& te eCist, dependin) on s8 &ators as te psial and emial arateristis o& te planet and its biospere, te biolo)ial and soial nat8re o& te i'iliation, and o& o8rse te ollision rate itsel&$ lanets (it i)er atmosperi press8res (ill be proteted a)ainst some(at lar)er 1mpators, alto8) te press8re annot be m8 )reater be&ore )reeno8se (armin) and oter onseK8enes make li&e improbable$ I& te )ra'it is m8 less tan on Eart, impators (ill make less ener)eti ollisions and te aard (ill be red8edGalto8) it annot be red8ed 'er m8 be&ore te atmospere esapes to spae$ e impat rate in oter planetar sstems is 8nertain$ 28r sstem ontains t(o maHor pop8lations o& small bodies tat &eed potential impators into Eart-rossin) orbits$ Bot te eCistene o& te so8re pop8lations and te meanisms tat maintain te ollision rate depend on o( (orlds are distrib8ted$ %or eCample, o8r 2ort +lo8d seems to a'e been pop8lat ed b )ra'itational eHetions o& i (orldlets &rom te 'iinit o& ran8s and Nept8ne$ I& tere are no planets tat pla te role o& ran8s and Nept8ne in sstems oter(ise like o8r o(n, teir 2ort +lo8ds ma be m8 more tinl pop8lated$ Stars in open and )lob8lar stellar l8sters, stars in do8ble or m8ltiple sstems, stars loser to te enter o& te /alaC, stars eCperienin) more &reK8ent eno8nters (it /iant ole8lar +lo8ds in interstellar spae, ma all eCperiene i)er impat &l8Ces at teir terrestrial planets$ e ometar &l8C mi)t be 8ndreds or to8sands o& times more at te Eart ad te planet >8piter ne'er &ormedGaordin) to a al8lation b /eor)e *eterill o& te +arne)ie Instit8tion o& *asin)ton$ In sstems (ito8t >8piter-like planets, te )ra'itational sield a)ainst omets is do(n, and i'iliation-treatenin) impats m8 more &reK8ent$ o a ertain eCtent, inreased &l8Ces o& interplanetar obHets mi)t inrease te rate o& e'ol8tion, as te mammals tat &lo8rised and di'ersi&ied a&ter te +retaeo8s-ertiar ollision (iped o8t te dinosa8rs$ B8t tere m8st be a point o& diminisin) ret8rns: +learl, some &l8C is too i) &or te ontin8ane o& an i'iliation$ 2ne onseK8ene o& tis train o& ar)8ment is tat, e'en i& i'iliations ommonl arise on planets tro8)o8t te /alaC, &e( o& tem (ill be bot lon)-li'ed and non-tenolo)ial$ Sine aards &rom asteroids and omets m8st appl to inabited planets all o'er te /alaC, i& tere are s8, intelli)ent bein)s e'er(ere (ill a'e to 8ni& teir ome (orlds politiall, lea'e teir
157
planets, and mo'e small nearb (orlds aro8nd$ eir e'ent8al oie, as o8rs, is spae&li)t or eCtintion$
+
E
19
EIN/ E .NES
*o o8ld den tat man o8ld someo( also make te ea'ens, o8ld e onl obtain te instr8ments and te ea'enl materialD GSI.I2 %I+IN2, E S2. 2% N =+$ 1474<
In te midst o& te Seond *orld *ar, a o8n) merian (riter named >ak *illiamson en'isioned a pop8lated Solar Sstem$ In te t(ent-seond ent8r, e ima)ined, #en8s (o8ld be settled b +ina,1 >apan, and Indonesia? ars b /erman? and te moons o& >8piter b 8ssia$ ose (o spoke En)lis, te lan)8a)e in (i *illiamson (as (ritin), (ere on&ined to te asteroids-and o& o8rse te Eart$ e stor, p8blised in A"ouning S7ien7e i7"ion in >8l 194", (as alled +ollision 2rbit and (ritten 8nder te pse8donm *ill Ste(art$ Its plot in)ed on te imminent ollision o& an 8ninabited asteroid (it a olonied one, and te sear &or a means o& alterin) te traHetories o& small (orlds$ lto8) no one on Eart (as endan)ered, tis ma a'e been te &irst appearane, apart &rom ne(spaper omi strips, o& asteroid ollisions as a treat to 8mans$ (#ome" impatin) te Eart ad been a staple peril$< e en'ironments o& ars and #en8s (ere poorl 8nderstood in te earl 1940s? it (as onei'able tat 8mans o8ld li'e tere (ito8t elaborate li&e-s8pport sstems$ B8t te asteroids (ere anoter matter$ It (as (ell kno(n, e'en ten, tat asteroids (ere small, dr, airless (orlds$ I& te (ere to be inabited, espeiall b lar)e n8mbers o& people, tese little (orlds (o8ld someo( a'e to be &iCed$ 1
In te real (orld, +inese spae o&&iials are proposin) to send a t(o-person astrona8t aps8le into orbit b te t8rn o& te ent8r$
It (o8ld be propelled b a modi&ied &ong Mar7 2E roket and be la8ned &rom te /obi !esert$ I& te +inese eonom eCibits e'en moderate ontin8in) )ro(tGm8 less te eCponential )ro(t tat marked it in te earl to mid-1990sG+ina ma be one o& te (orldAs leadin) spae po(ers b te middle o& te t(ent-&irst ent8r$ 2r earlier$
15;
In +ollision 2rbit, *illiamson portras a )ro8p o& spatial en)ineers, able to render s8 barren o8tposts lement$ +oinin) a (ord, *illiamson alled te proess o& metamorposis into an Eart-like (orld terra&ormin)$ e kne( tat te lo( )ra'it on an asteroid means tat an atmospere )enerated or transported tere (o8ld K8ikl esape to spae$ So is ke terra&ormin) tenolo) (as para)ra'it, an arti&iial )ra'it tat (o8ld old a dense atmospere$ s nearl as (e an tell toda, para)ra'it is a psial impossibilit$ B8t (e an ima)ine domed, transparent abitats on te s8r&aes o& asteroids, as s8))ested b onstantin siolko'sk, or omm8nities establised in te inie o& asteroids, as o8tlined in te 19"0s b te Britis sientist >$ !$ Bernal$ Bea8se asteroids are small and teir )ra'ities lo(, e'en massi'e s8bs8r&ae onstr8tion mi)t be omparati'el eas$ I& a t8nnel (ere d8) lean tro8), o8 o8ld H8mp in at one end and emer)e some 45 min8tes later at te oter, osillatin) 8p and do(n alon) te toll diameter o& tis (orld inde&initel$ Inside te ri)t kind o& asteroid, a arbonaeo8s one, o8 an &ind materials &or man8&at8rin) stone, metal, and plasti onstr8tion and plenti&8l (aterGall o8 mi)t need to b8ild a s8bs8r&ae losed eolo) ial sstem, an 8nder)ro8nd )arden$ Implementation (o8ld reK8ire a si)ni&iant step beond (at (e a'e toda, b8tG 8nlike para)ra'itGnotin) in s8 a seme seems impossible$ ll te elements an be &o8nd in ontemporar tenolo)$ I& tere (ere s8&&iient reason, a &air n8mber o& 8s o8ld be li'in) on =or in asteroids b te t(ent-seond ent8r$ e (o8ld o& o8rse need a so8re o& po(er, not H8st to s8stain temsel'es, b8t, as Bernal s8))ested, to mo'e teir asteroidal omes aro8nd$ =It does not seem so bi) a step &rom eCplosi'e alteration o& asteroid orbits to a more )entle means o& prop8lsion a ent8r or t(o later$< I& an oC)en atmospere (ere )enerated &rom emiall bo8nd (ater, ten or)anis o8ld be b8rned to )enerate po(er, H8st as &ossil &8els are b8rned on te Eart toda$ Solar po(er o8ld be onsidered, alto8) &or te main-belt asteroids te intensit o& s8nli)t is onl abo8t 10 perent (at it is on Eart$ Still, (e o8ld ima)ine 'ast &ields o& solar panels o'erin) te s8r&aes o& inabited asteroids and on'ertin) s8nli)t into eletriit$ oto'oltai tenolo) is ro8tinel 8sed in Eart-orbitin) spaera&t, and is in inreasin) 8se on te s8r&ae o& te Eart toda$ B8t (ile tat mi)t be eno8) to (arm and li)t te omes o& tese desendants, it does not seem adeK8ate to an)e asteroid orbits$ %or tat, *illiamson proposed 8sin) anti-matter$ ntimatter is H8st like ordinar matter, (it one si)ni&iant di&&erene$ +onsider dro)en: n ordinar dro)en atom onsists o& a positi'el ar)ed proton on te inside and a ne)ati'el ar)ed eletron on te o8tside$ n atom o& anti-dro)en onsists o& a ne)ati'el ar)ed proton on te inside and a positi'el ar)ed eletron =also alled a positron< on te o8tside$ e protons, (ate'er te si)n o& teir ar)es, a'e te same mass? and te eletrons, (ate'er te si)n o&
"eir ar)es, a'e te
same mass$ artiles (it opposite ar)es attrat$ dro)en atom and an anti-dro)en atom are bot stable, bea8se in bot ases te positi'e and ne)ati'e eletrial ar)es preisel balane$ nti-matter is not some potetial onstr8t &rom te per&er'id m8sin)s o& siene &ition (riters or teoretial psiists$ nti-matter eCists$ siists make it in n8lear 159
aelerators? it an be &o8nd in i)-ener) osmi ras$ So ( donAt (e ear more abo8t itD * as no one eld 8p a l8mp o& antimatter &or o8r inspetionD Bea8se matter and antimatter, (en bro8)t into ontat, 'iolentl anniilate ea oter, disappearin) in an intense b8rst o& )amma ras$ *e annot tell (eter sometin) is made o& matter or anti-matter H8st b lookin) at it$ e spetrosopi properties o&, &or eCample, dro)en and anti-dro)en are idential$ lbert EinsteinAs ans(er to te K8estion o& ( (e see onl matter and not anti-matter (as, atter (onGb (i e meant tat in o8r setor o& te ni'erse at least, a&ter almost all te matter and anti-matter interated and anniilated ea oter lon) a)o, tere (as some o& (at (e all ordinar matter le&t o'er$ 1 s &ar as (e an tell toda, &rom )amma ra astronom and oter means, te ni'erse is made almost entirel o& matter$ e reason &or tis en)a)es te deepest osmolo)ial iss8es, (i need not detain 8s ere$ B8t i& tere (as onl a onepartile-in-a-billion di&&erene in te preponderane o& matter o'er anti-matter at te be)innin), e'en tis (o8ld be eno8) to eCplain te ni'erse (e see toda$ *illiamson ima)ined tat 8mans in te t(ent-seond ent8r (o8ld mo'e asteroids aro8nd b te ontrolled m8t8al anniilation o& matter and anti-matter$ ll te res8ltin) )amma ras, i& ollimated, (o8ld make a potent roket eCa8st$ e anti-matter (o8ld be a'ailable in te main asteroid belt =bet(een te orbits o& ars and >8piter<, bea8se tis (as is eCplanation &or te exi"en7e o& te asteroid belt$ In te remote past, e proposed, an intr8der anti-matter (orldlet arri'ed in te Solar Sstem &rom te depts o& spae, impated, and anniilated (at (as ten an Eartlike planet, &i&t &rom te S8n$ e &ra)ments o& tis mi)t ollision are te asteroids, and some o& tem are still made o& anti-matter$ arness an anti-asteroidG*illiamson reo)nied tat tis mi)t be trikGand o8 an mo'e (orlds aro8nd at (ill$ t te time, *illiamsonAs ideas (ere &8t8risti, b8t &ar &rom &oolis$ Some o& +ollision 2rbit an be onsidered 'isionar$ oda, o(e'er, (e a'e )ood reason to belie'e tat tere are no si)ni&iant amo8nts o& anti-matter in te Solar Sstem, and tat te asteroid belt, &ar &rom bein) a &ra)mented terrestrial planet, is an enormo8s arra o& small bodies pre'ented =b te )ra'itational tides o& >8piter< &rom &ormin) an Eartlike (orld$ o(e'er, (e do )enerate ='er< small amo8nts o& antimatter in n8lear aelerators toda, and (e (ill probabl be able to man8&at8re m8 lar)er amo8nts b te t(ent-seond "
ent8r$ Bea8se it is so e&&iientGon'ertin) all o& te matter into ener), E X + , (it 100 perent e&&iienGperaps anti-matter en)ines (ill be a pratial tenolo) b ten, 'indiatin) *illiamson %ailin) tat, (at ener) so8res an (e realistiall eCpet to be a'ailable, to reon&i)8re asteroids, to li)t tem (arm tem, and mo'e tem aro8ndD e S8n sines b Hammin) protons to)eter and t8rnin) tem into eli8m n8lei$ Ener) is released in te proess, alto8) (it less tan 1 perent te e&&iien o& te anniilation o& matter and anti-matter$ B8t e'en proton-proton reations are &ar beond antin) (e an realistiall ima)ine &or o8rsel'es in te near &8t8re$ e reK8ired temperat8res are m8 too 1
I& it ad been te oter (a, ten (e and e'ertin) else in tis part o& te ni'erse (o8ld be made o& anti-matter$ *e (o8ld, o& o8rse, all it matterGand te idea o& (orlds and li&e made o& tat oter kind o& material$ te st8&& (it te eletrial ar)es re'ersed, (eAd onsider (ildl spe8lati'e$
160
i)$ Instead< o& Hammin) protons to)eter, to8), (e mi)t 8se ea'ier kinds o& dro)en$ *e alread do so in termon8lear (eapons$ !e8teri8m is a proton bo8nd b n8lear &ores to a ne8tron? triti8m is a proton bo8nd b n8lear &ores to t(o ne8trons$ It seems likel tat in anoter ent8r (e (ill a'e pratial po(er semes tat in'ol'e te ontrolled &8sion o& de8teri8m and triti8m, and o& de8teri8m and eli8m$ !e8teri8m and triti8m are present as minor onstit8ents in (ater =on Eart and oter (orlds<$ e kind o& eli8m needed &or &8sion, 3e =t(o protons and a ne8tron make 8p its n8le8s<, as been implanted o'er billions o& ears b te solar (ind in te s8r&aes o& te asteroids$ ese proesses are not nearl as e&&iient as te proton-proton reations in te S8n, b8t te o8ld pro'ide eno8) po(er to r8n a small it &or a ear &rom a lode o& ie onl a &e( meters in sie$ %8sion reators seem to be omin) alon) too slo(l to pla a maHor role in sol'in), or e'en si)ni&iantl miti)atin), )lobal (armin)$ B8t b te t(ent-seond ent8r, te o8)t to be (idel a'ailable$ *it &8sion roket en)ines, it (ill be possible to more asteroids and omets aro8nd te inner Solar Sstem takin) a main-belt asteroid, &or eCample, and insertin) it into orbit aro8nd te Eart$ (orld 10 kilometers aross o8ld be transported &rom Sat8rn, sa, to ars tro8) n8lear b8rnin) o& te dro)en in an i omet a kilometer aross$ =)ain, IAm ass8min) a time o& m8 )reater politial stabilit and sa&et$<
PUT ASIDE FOR THE MOMENT an
K8alms o8 mi)t a'e abo8t te etis o& rearran)in)
(orlds, or o8r abilit to do so (ito8t atastropi onseK8enes$ !i))in) o8t te insides o& (orldlets, reon&i)8rin) tem &or 8man abitation, and mo'in) tem &rom one plae in te Solar Sstem to anoter seems to be (itin o8r )rasp in anoter ent8r or t(o$ eraps b ten (e (ill a'e adeK8ate international sa&e)8ards as (ell$ B8t (at abo8t trans&ormin) te s8r&ae en'ironments not o& asteroids or omets, b8t o& planetsD +o8ld (e li'e on arsD I& (e (anted to set 8p o8sekeepin) on ars, itAs eas to see tat, in priniple at least, (e o8ld do it: ereAs ab8ndant s8nli)t$ ereAs plenti&8l (ater in te roks and in 8nder)ro8nd and polar ie$ e atmospere is mostl arbon dioCide$ It seems likel tat in sel&-ontained abitats-peraps domed enlos8resG(e o8ld )ro( rops, man8&at8re oC)en &rom (ater, rele (astes$ t &irst (eAd be dependent on ommodities res8p plied &rom Eart, b8t in time (eAd man8&at8re more and more o& tem o8rsel'es$ *eAd beome inreasin)l sel&-s8&&iient$ e domed enlos8res, e'en i& made o& ordinar )lass, (o8ld let in te 'isible s8nli)t and sreen o8t te S8nAs 8ltra'iolet ras$ *it oC)en masks and proteti'e )armentsGb8t notin) as b8lk and 8mbersome as a spaes8itG(e o8ld lea'e tese enlos8res to )o eCplorin), or to b8ild anoter domed 'illa)e and &arms$ It seems 'er e'oati'e o& te merian pioneerin) eCperiene, b8t (it at least one maHor di&&erene: In te earl sta)es, lar)e s8bsidies are essential$ e tenolo) reK8ired is too eCpensi'e &or some poor &amil, like m )randparents a ent8r a)o, to pa teir o(n passa)e to ars$ e earl artian pioneers (ill be sent b )o'ernments and (ill a'e i)l speialied skills$ B8t in a )eneration or t(o, (en ildren and )randildren are born tereG 161
and espeiall (en sel&-s8&&iien is (itin reaGtat (ill be)in to an)e$ o8n)sters born on ars (ill be )i'en speialied trainin) in te tenolo) essential &or s8r'i'al in tis ne( en'ironment$ e settlers (ill beome less eroi and less eCeptional$ e &8ll ran)e o& 8man stren)ts and de&iienies (ill be)in to assert temsel'es$ /rad8all, preisel bea8se o& te di&&i8lt o& )ettin) &rom Eart to ars, a 8niK8e artian 8lt8re (ill be)in to emer)eG distint aspirations and &ears tied to te en'ironment te li'e in, distint tenolo)ies, distint soial problems, distint sol8tionsGand, as as o8rred in e'er similar ir8mstane tro8)o8t 8man istor, a )rad8al sense o& 8lt8ral and politial estran)ement &rom te moter (orld$ /reat sips (ill arri'e arrin) essential tenolo) &rom Eart, ne( &amilies o& settlers, sare reso8res$ It is ard to kno(, on te basis o& o8r limited kno(led)e o& ars, (eter te (ill )o ome emptGor (eter te (ill arr (it tem sometin) &o8nd onl on ars, sometin) onsidered 'er 'al8able on Eart$ Initiall m8 o& te sienti&i in'esti)ation o& samples o& te artian s8r&ae (ill be done on Eart$ B8t in time te sienti&i st8d o& ars =and its moons obos and !eimos< (ill be done &rom ars$ E'ent8allGas as appened (it 'irt8all e'er oter &orm o& 8man transportationG interplanetar tra'el (ill beome aessible to people o& ordinar means: to sientists p8rs8in) teir o(n resear proHets, to settlers &ed 8p (it Eart, e'en to 'ent8resome to8rists$ nd o& o8rse tere (ill be eCplorers$ I& te time e'er ame (en it (as possible to make te artian en'ironment m8 more Eart-likeGso proteti'e )arments, oC)en masks, and domed &armlands and ities o8ld be dispensed (itGte attration and aessibilit o& ars (o8ld be inreased man-&old$ e same, o& o8rse, (o8ld be tr8e &or an oter (orld (i o8ld be en)ineered so tat 8mans o8ld li'e tere (ito8t elaborate ontri'anes to keep te planetar en'ironment o8t$ *e (o8ld &eel m8 more om&ortable in o8r adopted ome i& an intat dome or spaes8it (erenAt all tat stood bet(een 8s and deat$ =B8t peraps I eCa))erate te dan)ers$ eople (o li'e in te Neterlands seem at least as (ell adH8sted and are&ree as oter inabitants o& Nortern E8rope? 'et teir dikes are all tat stand bet(een tem and te sea$ eo)niin) te spe8lati'e nat8re o& te K8estion and te limitations in o8r kno(led)e, is it ne'erteless possible to en'ision terra&ormin) te planetsD *e need look no &8rter tan o8r o(n (orld to see tat 8mans are no( able to alter planetar en'ironments in a pro&o8nd (a$ !epletion o& te oone laer, )lobal (armin) &rom an inreased )reeno8se e&&et, and )lobal oolin) &rom n8lear (ar are all (as in (i present tenolo) an si)ni&iantl alter te en'ironment o& o8r (orldGand in ea ase as an inad'ertent onseK8ene o& doin) sometin) else$ I& (e ad in"ene to alter o8r planetar en'ironment, (e (o8ld be &8ll able to )enerate still )reater an)e$ s o8r tenolo) beomes more po(er&8l, (e (ill be able to (ork still more pro&o8nd an)es$ B8t H8st as =in parallel parkin)< itAs easier to )et o8t o& a parkin) plae tan into one, itAs easier to destro a planetar en'ironment tan to mo'e it into a narro(l presribed ran)e o& temperat8res, press8res, ompositions, and so on$ *e alread kno( o& a m8ltit8de o& desolate and 8ninabitable (orlds, andG(it 'er narro( mar)insGonl one )reen and lement one$ 16"
is is a maHor onl8sion &rom earl in te era o& spaera&t eCploration o& te Solar Sstem$ In alterin) te Eart, or an (orld (it an atmospere, (e m8st be 'er are&8l abo8t positi'e &eedbaks, (ere (e n8d)e an en'ironment a little bit and it takes o& on its o(nGa little oolin) leadin) to r8na(a )laiation, as ma a'e appened on ars, or a little (armin) to a r8na(a )reeno8se e&&et, as appened on #en8s$ It is not at all lear tat o8r kno(led)e is s8&&iient to tis p8rpose$ s &ar as I kno(, te &irst s8))estion in te sienti&i literat8re abo8t terra&ormin) te planets (as made in a 1961 artile I (rote abo8t #en8s$ I (as prett s8re ten tat #en8s ad a s8r&ae temperat8re (ell abo'e te normal boilin) point o& (ater, prod8ed b a arbon dioCide(ater 'apor )reeno8se e&&et$ I ima)ined seedin) its i) lo8ds (it )enetiall en)ineered miroor)anisms tat (o8ld take +2
",
N", and "2 o8t o& te atmospere and
on'ert tem into or)ani mole8les$ e more +2 " remo'ed, te smaller te )reeno8se e&&et and te ooler te s8r&ae$ e mirobes (o8ld be arried do(n tro8) te atmospere to(ard te )ro8nd, (ere te (o8ld be &ried, so (ater 'apor (o8ld be ret8rned to te atmospere? b8t te arbon &rom te +2 " (o8ld be on'erted irre'ersibl b te i) temperat8res into )rapite or some oter in'olatile &orm o& arbon$ E'ent8all, te temperat8res (o8ld &all belo( te boilin) point and te s8r&ae o& #en8s (o8ld beome abitable, dotted (it pools and lakes o& (arm (ater$ e idea (as soon taken 8p b a n8mber o& siene &ition a8tors in te ontin8in) dane bet(een siene and siene &itionGin (i te siene stim8lates te &ition, and te &ition stim8lates a ne( )eneration o& sientists, a proess bene&itin) bot )enres$ B8t as te neCt step in te dane, it is no( lear tat seedin) #en8s (it speial potosnteti miroor)anisms (ill not (ork$ Sine 1961 (eA'e diso'ered tat te lo8ds o& #en8s are a onentrated sol8tion o& s8l&8ri aid, (i makes te )eneti en)ineerin) rater more allen)in)$ B8t tat in itsel& is not a &atal &la($ =ere are miroor)anisms tat li'e o8t teir li'es in onentrated sol8tions o& s8l&8ri aid$< ereAs te &atal &la(: In 1961 I to8)t te atmosperi press8re at te s8r&ae o& #en8s N[-as a &e( bars, a &e( times te s8r&ae press8re on Eart$ *e no( kno( it to be 90 bars, so tat i& te seme (orked, te res8lt (o8ld be a s8r&ae b8ried in 8ndreds o& meters o& &ine )rapite, and an atmospere made o& 65 bars o& almost p8re mole8lar oC)en$ *eter (e (o8ld &irst implode 8nder te atmosperi press8re or spontaneo8sl b8rst into &lames in all tat oC)en is an open K8estion$ o(e'er, lon) be&ore so m8 oC)en o8ld b8ild 8p, te )rapite (o8ld spontaneo8sl b8rn bak into +2 ", sort-ir8itin) te proess$ t best, s8 a seme an arr te terra&ormin) o& #en8s onl part(a$ .etAs ass8me tat b te earl t(ent-seond ent8r (e a'e omparati'el ineCpensi'e ea'-li&t 'eiles, so (e an arr lar)e paloads to oter (orlds? ab8ndant and po(er&8l &8sion reators? and (ell-de'eloped )eneti en)ineerin)$ ll tree ass8mptions are likel, )i'en 8rrent trends$ +o8ld (e terra&orm te planetsD 1 >ames ollak o& NSAs mes esear 1
*illiamson, ro&essor Emerit8s o& En)lis at Eastern Ne( eCio ni'ersit at a)e ;5 (rote to me tat e (as amaed to see o( &ar at8al siene as ome sine e &irst s8))ested terra&ormin) oter (orlds$ *e are a8m8latin) te tenolo) tat (ill one da permit terra&ormin), b8t at present all A#-a a'e are s8))estions b and lar)e less )ro8nd breakin) tan *illiamsonAs ori)inal ideas$
163
+enter and I s8r'eed tis problem$ ereAs a s8mmar o& (at (e &o8nd: #ENS: +learl te problem (it #en8s is its massi'e )reeno8se e&&et$ I& (e o8ld red8e te )reeno8se e&&et almost to ero, te limate mi)t be balm$ B8t a 90-bar +2 " atmospere is oppressi'el tik$ 2'er e'er posta)e stamp-sied sK8are in o& s8r&ae, te air (ei)s as m8 as siC pro&essional &ootball plaers, piled one on top o& anoter$ akin) all tat )o a(a (ill take some doin)$ Ima)ine bombardin) #en8s (it asteroids and omets$ Ea impat (o8ld blo( a(a some o& te atmospere$ o blo( a(a almost all o& it, to8), (o8ld reK8ire 8sin) 8p more bi) asteroids and omets tan tere areGat least in te planetar part o& te Solar Sstem$ E'en i& tat man potential impators eCisted, e'en i& (e o8ld make tem all ollide (it #en8s =tis is te o'erkill approa to te impat aard problem<, tink (at (e (o8ld a'e lost$ *o kno(s (at (onders, (at pratial kno(led)e te ontainD *e (o8ld also obliterate m8 o& #en8sA )or)eo8s s8r&ae )eolo)G(i (eA'e H8st be)8n to 8nderstand, and (i ma tea 8s m8 abo8t te Eart$ is is an eCample o& br8te&ore terra&ormin)$ I s8))est (e (ant to steer entirel lear o& s8 metods, e'en i& someda (eAll be able to a&&ord tem =(i I 'er m8 do8bt<$ *e (ant sometin) more ele)ant, more s8btle, more respet&8l o& te en'ironments o& oter (orlds$ mirobial approa as some o& tose 'irt8es, b8t does not do te trik, as (eA'e H8st seen$ *e an ima)ine p8l'eriin) a dark asteroid and spreadin) te po(der tro8) te 8pper atmospere o& #en8s, or arrin) s8 d8st 8p &rom te s8r&ae$ is (o8ld be te psial eK8i'alent o& n8lear (inter or te +retaeo8s-ertiar post-impat limate$ I& te s8nli)t reain) te )ro8nd is s8&&iientl atten8ated, te s8r&ae temperat8re m8st &all$ B8t b its 'er nat8re, tis option pl8n)es #en8s into deep )loom, (it datime li)t le'els peraps onl as bri)t as on a moonlit ni)t on Eart$ e oppressi'e, r8sin) 90-bar atmospere (o8ld remain 8nto8ed$ Sine te emplaed d8st (o8ld sediment o8t e'er &e( ears, te laer (o8ld a'e to be replenised in te same period o& time$ eraps s8 an approa (o8ld be aeptable &or sort eCplorator missions, b8t te en'ironment )enerated seems 'er stark &or a sel&-s8stainin) 8man omm8nit on #en8s$ *e o8ld 8se a )iant arti&iial s8nsade in orbit aro8nd #en8s to ool te s8r&ae? b8t it (o8ld be enormo8sl eCpensi'e, as (ell as a'in) man o& te de&iienies o& te d8st laer$ o(e'er, i& te temperat8res o8ld be lo(ered s8&&iientl, te +2 " in te atmospere (o8ld rain o8t$ ere (o8ld be a transitional time o& +2 " oeans on #en8s$ I& tose oeans o8ld be o'ered o'er to pre'ent re-e'aporationG&or eCample, (it (ater oeans made b meltin) a lar)e, i moon transported &rom te o8ter Solar SstemGten te +2 " mi)t onei'abl be seK8estered a(a, and #en8s on'erted into a (ater =or lo(-&i selter< planet$ *as a'e also been s8))ested to on'ert te +2" into arbonate rok$ 8s all proposals &or terra&ormin) #en8s are still br8te-&ore, inele)ant, and abs8rdl eCpensi'e$ e desired planetar metamorposis ma be beond o8r rea &or a 'er lon) time,
164
e'en i& (e to8)t it (as desirable and responsible$ e sian oloniation o& #en8s tat >ak *illiamson ima)ined ma a'e to be redireted some(ere else$
S: %or ars (e a'e H8st te opposite problem$ ereAs not enoug )reeno8se e&&et$ e planet is a &roen desert$ B8t te &at tat ars seems to a'e ad ab8ndant ri'ers, lakes, and peraps e'en oeans 4 billion ears a)oGat a time (en te S8n (as less bri)t tan it is todaGmakes o8 (onder i& tereAs sol'e nat8ral instabilit in te artian limate, sometin) on air tri))er tat one released (o8ld all b itsel& ret8rn te planet to its anient lement state$ =.etAs note &rom te start tat doin) so (o8ld destro artian land&orms tat old ke data on te pastGespeiall te laminated polar terrain$< s (e kno( 'er (ell &rom Eart and #en8s, arbon dioCide is a )reeno8se )as$ ere are arbonate minerals &o8nd on ars, and dr ie in one o& te polar aps$ e o8ld be on'erted into +2" )as$ B8t to make eno8) o& a )reeno8se e&&et to )enerate om&ortable temperat8res on ars (o8ld reK8ire te entire s8r&ae o& te planet to be plo(ed 8p and proessed to a dept o& kilometers$ part &rom te da8ntin) obstales in pratial en)ineerin) tat tis representsG &8sion po(er or no &8sion po(erGand te inon'eniene to (ate'er sel&-ontained, losed eolo)ial sstems 8mans ad alread establised on te planet it (o8ld also onstit8te te irresponsible destr8tion o& a 8niK8e sienti&i reso8re and database, te artian s8r&ae$ *at abo8t oter )reeno8se )asesD lternati'el, (e mi)t take loro&l8oroarbons =+%+s or +%+s< to ars a&ter man8&at8rin) tem on Eart$ ese are arti&iial s8bstanes tat, so &ar as (e kno(, are &o8nd no(ere else in te Solar Sstem$ *e an ertainl ima)ine man8&at8rin) eno8) +%+s on Eart to (arm ars, bea8se b a77ien" in a &e( deades (it present tenolo) on Eart (eA'e mana)ed to sntesie eno8) to ontrib8te to )lobal (armin) on o8r planet$ ransportation to ars (o8ld be eCpensi'e, to8): E'en 8sin) Sa"urn
V- or Energi$a-lass boosters it (o8ld reK8ire at least a la8n a da &or a ent8r$ B8t peraps te o8ld be man8&at8red &rom &l8orine-ontainin) minerals on ars$ ere is, in addition, a serio8s dra(bak: 2n ars as on Eart, ab8ndant +%+s (o8ld pre'ent &ormation o& an oone laer$ +%+s mi)t brin) artian temperat8res into a lement ran)e, b8t )8arantee tat te solar 8ltra'iolet aard (o8ld remain eCtremel serio8s$ eraps te solar 8ltra'iolet li)t o8ld be absorbed b an atmosperi laer o& p8l'eried asteroidal or s8r&ae debris inHeted in are&8ll titrated amo8nts abo'e te +%+s$ B8t no( (eAre in te tro8blin) ir8mstane o& a'in) to deal (it propa)atin) side e&&ets, ea o& (i reK8ires its o(n lar)e-sale tenolo)ial sol8tion$ tird possible )reeno8se )as &or (armin) ars is ammonia =N 3<$ 2nl a little ammonia (o8ld be eno8) to (arm te artian s8r&ae to abo'e te &reein) point o& (ater$ In priniple, tis mi)t be done b speiall en)ineered miroor)anisms tat (o8ld on'ert artian atmosperi N" to N3 as some mirobes do on Eart, b8t do it 8nder artian onditions$ 2r te same on'ersion mi)t be done in speial &atories$ lternati'el, te nitro)en reK8ired o8ld be arried to ars &rom else(ere in te Solar Sstem$ =N 165
"
is te prinipal onstit8ent in te
atmosperes o& bot Eart and itan$< ltra'iolet li)t (o8ld on'ert ammonia bak into N " in abo8t 30 ears, so tere (o8ld a'e to be a ontin8o8s res8ppl o& N 3$ H8diio8s ombination o& +2 ", +%+, and N 3 )reeno8se e&&ets on ars looks as i& it mi)t be able to brin) s8r&ae temperat8res lose eno8) to te &reein) point o& (ater &or te seond pase o& artian terra&ormin) to be)inGtemperat8res risin) d8e to te press8re o& s8bstantial (ater 'apor in te air, (idespread prod8tion o& 2 " b )enetiall en)ineered plants, and &ine-t8nin) te s8r&ae en'ironment$ irobes and lar)er plants and animals o8ld be establised on ars be&ore te o'erall en'ironment (as s8itable &or 8nproteted 8man settlers$ erra&ormin) ars is plainl m8 easier tan terra&ormin) #en8s$ B8t it is still 'er eCpensi'e b present standards, and en'ironmentall destr8ti'e$ I& tere (ere s8&&iient H8sti&iation, to8), peraps te terra&ormin) o& ars o8ld be 8nder (a b te t(ent-seond ent8r$
E 22NS 2% >IE N! SN: erra&ormin) te satellites o& te >o'ian planets presents 'arin) de)rees o& di&&i8lt$ eraps te easiest to ontemplate is itan$ It alread as an atmospere, made mainl o& N " like te EartAs, and is m8 loser to terrestrial atmosperi press8res tan eiter #en8s or ars$ oreo'er, important )reeno8se )ases, s8 as N3 and "0, are almost ertainl &roen o8t on its s8r&ae$ an8&at8re o& initial )reeno8se )ases tat do not &reee o8t at present itan temperat8res pl8s diret (armin) o& te s8r&ae b n8lear &8sion o8ld, it seems, be te ke earl steps to one da terra&orm itan$ IF THERE WERE A COMPELLING REA SON&or
terra&ormin) oter (orlds, tis )reatest o& en)ineerin) proHets mi)t be &easible on te timesale (eA'e been desribin)Gertainl &or asteroids, possibl &or ars, itan, and oter moons o& te o8ter planets, and probabl not &or #en8s$ ollak and I reo)nied tat tere are tose (o &eel a po(er&8l attration to te idea o& renderin) oter (orlds in te Solar Sstem s8itable &or 8man abitationGin establisin) obser'atories, eCplorator bases, omm8nities, and omesteads tere$ Bea8se o& its pioneerin) istor, tis ma be a parti8larl nat8ral and attrati'e idea in te nited States$ In an ase, massi'e alteration o& te en'ironments o& oter (orlds an be done ompetentl and responsibl onl (en (e a'e a m8 better 8nderstandin) o& tose (orlds tan is a'ailable toda$ d'oates o& terra&ormin) m8st &irst beome ad'oates o& te lon)-term and toro8) sienti&i eCploration o& oter (orlds$ eraps (en (e reall 8nderstand te di&&i8lties o& terra&ormin), te osts or te en'ironmental penalties (ill pro'e too steep , and (e (ill lo(er o8r si)t s to domed or s8bs8r&ae ities or oter loal, losed eolo)ial sstems, )reatl impro'ed 'ersions o& Biospere II, on oter (orlds$ eraps (e (ill abandon te dream o& on'ertin) te s8r&aes o& oter (orlds to sometin) approain) te EartAs$ 2r peraps tere are m8 more ele)ant, ost-e&&eti'e, and en'ironmentall responsible (as o& terra&ormin) tat (e a'e not et ima)ined$
166
B8t i& (e are serio8sl to p8rs8e te matter, ertain K8estions o8)t to be asked: /i'en tat an terra&ormin) seme entails a balane o& bene&its a)ainst osts, o( ertain m8st (e be tat ke sienti&i in&ormation (ill not tereb be destroed be&ore proeedin)D o( m8 8nderstandin) o& te (orld in K8estion do (e need be&ore planetar en)ineerin) an be relied 8pon to prod8e te desired end stateD +an (e )8arantee a lon)-term 8man ommitment to maintain and replenis an en)ineered (orld, (en 8man politial instit8tions are so sort li'edD I& a (orld is e'en onei'abl inabitedGperaps onl b miroor)anismsGdo 8mans a'e a ri)t to alter itD *at is o8r responsibilit to preser'e te (orlds o& te Solar Sstem in teir present (ilderness states &or &8t8re )enerations-(o ma ontemplate 8ses tat toda (e are too i)norant to &oreseeD ese K8estions ma peraps be enaps8lated into a &inal K8estion: +an (e, (o a'e made s8 a mess o& "i (orld, be tr8sted (it otersD It is H8st onei'able tat some o& te teniK8es tat mi)t e'ent8all terra&orm oter (orlds mi)t be applied to ameliorate te dama)e (e a'e done to tis one$ +onsiderin) te relati'e 8r)enies, a 8se&8l indiation o& (en te 8man speies is read to onsider terra&ormin) serio8sl is (en (e a'e p8t o8r o(n (orld ri)t$ *e an onsider it a test o& te dept o& o8r 8nderstandin) and o8r ommitment$ e &irst step in en)ineerin) te Solar Sstem is to )8arantee te abitabilit o& te Eart$ en (eAll be read to spread o8t to asteroids, omets, ars, te moons o& te o8ter Solar Sstem, and beond$ >ak *illiamson As predition tat tis (ill be)in to ome abo8t b te t(ent-seond ent8r ma not be &ar o&& te mark$ THE NOTION OF OUR DESCENDANTSli'in)
and (orkin) on oter (orlds, and e'en mo'in)
some o& tem aro8nd &or teir on'eniene, seems te most eCtra'a)ant siene &ition$ Be realisti, a 'oie inside m ead o8nsels$ B8t tis is realisti$ *eAre on te 8sp o& te tenolo), near te midpoint bet(een impossible and ro8tine$ ItAs eas to be on&lited abo8t it$ I& (e donAt do sometin) a(&8l to o8rsel'es in te interim, in anoter ent8r terra&ormin) ma seem no more impossible tan a 8man-tended spae station does toda$ I tink te eCperiene o& li'in) on oter (orlds is bo8nd to an)e 8s$ 28r desendants, born and raised else(ere, (ill nat8rall be)in to o(e primar loalt to te (orlds o& teir birt, (ate'er a&&etion te retain &or te Eart$ eir psial needs, teir metods o& s8pplin) tose needs, teir tenolo)ies, and teir soial str8t8res (ill all a'e to be di&&erent$ blade o& )rass is a ommonplae on Eart? it (o8ld be a mirale on ars$ 28r desendants on ars (ill kno( te 'al8e o& a pat o& )reen$ nd i& a blade o& )rass is prieless, (at is te 'al8e o& a 8man bein)D e merian re'ol8tionar om aine, in desribin) is ontemporaries, ad to8)ts alon) tese lines: e (ants (i neessaril aompan te 8lti'ation o& a (ilderness prod8ed amon) tem a state o& soiet (i o8ntries lon) arassed b te K8arrels and intri)8es o& )o'ernments ad ne)leted to eris$ In s8 a sit8ation man beomes (at e o8)t to be$ e sees is speies $ $ $ as kindred$
167
a'in) seen at &irst and a proession o& barren and desolate (orlds, it (ill be nat8ral &or o8r spae&arin) desendants to eris li&e$ a'in) learned sometin) &rom te ten8re o& o8r speies on Eart, te ma (is to appl tose lessons to oter (orldsGto spare )enerations to ome te a'oidable s8&&erin) tat teir anestors (ere obli)ed to end8re, and to dra( 8pon o8r eCperiene and o8r mistakes as (e be)in o8r open-ended e'ol8tion into spae$
C
H
A
P
T
E
R
20
!NESS %ar a(a, idden &rom te ees o& dali)t, tere are (aters in te skies$ —EII!ES, /E >A##AE C#A3 F06 >3#3)
16;
As
ildren, (e &ear te dark$ n tin) mi)t be o8t$ ere$ e 8nkno(n tro8bles 8s$
Ironiall, it is o8r &ate to li'e in te dark$ is 8neCpeted &indin) o& siene is onl abo8t tree ent8ries old$ ead o8t &rom te Eart in an diretion o8 oose, andGa&ter an initial &las o& bl8e and a lon)er (ait (ile te S8n &adesGo8 are s8rro8nded b blakness, p8nt8ated onl ere and tere b te &aint and distant stars$ E'en a&ter (e are )ro(n, te darkness retains its po(er to &ri)ten 8s$ nd so tere are tose (o sa (e so8ld not inK8ire too losel into (o else mi)t be li'in) in tat darkness$ Better not to kno(, te sa$ ere are 400 billion stars in te ilk *a /alaC$ 2& tis immense m8ltit8de, o8ld it be tat o8r 8mdr8m S8n is te onl one (it an inabited planetD abe$ abe te ori)in o& li&e or intelli)ene is eCeedin)l improbable$ 2r mabe i'iliations arise all te time, b8t (ipe temsel'es o8t as soon as te are able$ 2r, ere and tere, peppered aross spae, orbitin ) oter s8ns, mabe tere are (orlds sometin) like o8r o(n, on (i oter bein)s )ae 8p and (onder as (e do abo8t (o else li'es in te dark$ +o8ld te ilk *a be ripplin) (it li&e and intelli)eneG(orlds allin) o8t to (orldsG(ile (e on Eart are ali'e at te ritial moment (en (e &irst deide to listenD 28r speies as diso'ered a (a to omm8niate tro8) te dark, to transend immense distanes$ No means o& omm8niation is &aster or eaper or reaes o8t &arter$ ItAs alled radio$ &ter billions o& ears o& biolo)ial e'ol8tionGon teir planet and o8rsGan alien i'iliation annot be in tenolo)ial lokstep (it 8s$ ere a'e been 8mans &or more tan t(ent to8sand ent8ries, b8t (eA'e ad radio onl &or abo8t one ent8r$ I& alien i'iliations are beind 8s, teAre likel to be too &ar beind to a'e radio$ nd i& teAre aead o& 8s, teAre likel to be &ar aead o& 8s$ ink o& te tenial ad'anes on o8r (orld o'er H8st te last &e( ent8ries$ *at is &or 8s tenolo)iall di&&i8lt or impossible, (at mi)t seem to 8s like ma)i, mi)t &or tem be tri'iall eas$ e mi)t 8se oter, 'er ad'aned means to omm8niate (it teir peers, b8t te (o8ld kno( abo8t radio as an approa to ne(l emer)in) i'iliations$ E'en (it no more tan o8r le'el o& tenolo) at te transmittin) and reei'in) ends, (e o8ld omm8niate toda aross m8 o& te /alaC$ e so8ld be able to do m8 better$ I& te eCist$ B8t o8r &ear o& te dark rebels$ e idea o& alien bein)s tro8bles 8s$ *e onH8re 8p obHetions:
H!" "oo expeni4e3H B8t, in its &8llest modern tenolo)ial eCpression, it osts less tan one attak eliopter a ear$
169
H:ell ne4er uner"an <a" "e$re a$ing3H B8t, bea8se te messa)e -is transmitted b radio, (e and te m8st a'e radio psis, radio astronom, and radio tenolo) in ommon$ e la(s o& Nat8re are te same e'er(ere? so siene itsel& pro'ides a means and lan)8a)e o& omm8niation e'en bet(een 'er di&&erent kinds o& bein)sGpro'ided te bot a'e siene$ %i)8rin) o8t te messa)e, i& (eAre &ort8nate eno8) to reei'e one, ma be m8 easier tan aK8irin) it$
H!"
HAll "roug i"or$ a4an7e 7i4ili+a"ion a4e ruine 7i4ili+a"ion u" lig"l$ more ;a7k
THE DEBATE IS,
&or te moment, moot$ *e are no(, on an 8npreedented sale, listenin) &or
radio si)nals &rom possible oter i'iliations in te depts o& spae$ li'e toda is te &irst )eneration o& sientists to interro)ate te darkness$ +onei'abl it mi)t also be te last )eneration be&ore ontat is madeGand tis te last moment be&ore (e diso'er tat someone in te darkness is allin) o8t to 8s$ is K8est is alled te Sear &or ECtraterrestrial Intelli)ene =SEI<$ .et me desribe o( &ar (eA'e ome$ e &irst SEI pro)ram (as arried o8t b %rank !rake at te National adio stronom 2bser'ator in /reenbank, *est #ir)inia, in 1960$ e listened to t(o nearb S8n-like stars &or t(o (eeks at one parti8lar &reK8en$ =Nearb is a relati'e term: e nearest (as 1" li)tearsG70 trillion milesGa(a$< lmost at te moment !rake pointed te radio telesope and t8rned te sstem on, e piked 8p a 'er stron) si)nal$ *as it a messa)e &rom alien bein)sD en it (ent a(a$ I& te si)nal disappears, o8 anAt sr8tinie it$ o8 anAt see i&, bea8se o& te EartAs rotation, it mo'es (it te sk$ I& itAs not repeatable, o8A'e learned almost notin) &rom itGit mi)t be terrestrial radio inter&erene, or a &ail8re o& o8r ampli&ier or detetor $ $ $ or an alien si)nal$ nrepeatable data, no matter o( ill8strio8s te sientist reportin) tem, are not (ort m8$ *eeks later, te si)nal (as deteted a)ain$ It t8rned o8t to be a mil itar airra&t 1
S8rprisin)l man people, inl8din) Ne( ork imes editorialists, are onerned tat one eCtraterrestrials kno( (ere (e are, te (ill ome ere and eat 8s$ 8t aside te pro&o8nd biolo)ial di&&erenes tat m8st eCist bet(een te potetial aliens and o8rsel'es? ima)ine tat (e onstit8te an interstellar )astronomi delia$ * transport lar)e n8mbers o& 8s to alien resta8rantsD e &rei)ta)e is enormo8s$ *o8ldnAt it be better H8st to steal a &e( 8mans, seK8ene o8r amino aids or (ate'er else is te so8re o& o8r deletabilit, and ten H8st sntesie te idential &ood prod8t &rom sratD
170
broadastin) on an 8na8toried &reK8en$ !rake reported ne)ati'e res8lts$ B8t in siene a ne)ati'e res8lt is not at all te same tin) as a &ail8re$ is )reat aie'ement (as to so( tat modern tenolo) is &8ll able to listen &or si)nals &rom potetial i'iliations on te planets o& oter stars$ Sine ten tereA'e been a n8mber o& attempts, o&ten on time borro(ed &rom oter radio telesope obser'in) pro)rams, and almost ne'er &or lon)er tan a &e( monts$ ereA'e been some more &alse alarms, at 2io State, in reibo, 8erto io, in %rane, 8ssia, and else(ere, b8t notin) tat o8ld pass m8ster (it te (orld sienti&i omm8nit$ ean(ile, te tenolo) &or detetion as been )ettin) eaper? te sensiti'it keeps impro'in)? te sienti&i respetabilit o& SEI as ontin8ed to )ro(? and e'en NS and +on)ress a'e beome a little less a&raid to s8pport it$ !i'erse, omplementar sear strate)ies are possible and neessar$ It (as lear ears a)o tat i& te trend ontin8ed, te tenolo) &or a ompreensi'e SEI e&&ort (o8ld e'ent8all &all (itin te rea e'en o& pri'ate or)aniations =or (ealt indi'id8als
nonpro&it membersip or)aniation tat Br8e 8rra, ten te !iretor o& >., and I &o8nded in 19;0Gis de'oted to planetar eCploration and te sear &or eCtraterrestrial li&e$ a8l oro(it, a psiist at ar'ard ni'ersit, ad made a n8mber o& important inno'ations &or SEI and (as ea)er to tr tem o8t$ I& (e o8ld &ind te mone to )et im started, (e to8)t (e o8ld ontin8e to s8pport te pro)ram b donations &rom o8r members$ In 19;3 nn !r8an and I s8))ested to te &ilmmaker Ste'en Spielber ) tat tis (as an ideal proHet &or im to s8pport$ Breakin) (it oll(ood tradition, e ad in t(o (ildl s8ess&8l mo'ies on'eed te idea tat eCtraterrestrial bein)s mi)t not be ostile and dan)ero8s$ Spielber) a)reed$ *it is initial s8pport tro8) e lanetar Soiet, roHet E be)an$ E is an aronm &or e)aannel ECtraerrestrial ssa$ e sin)le &reK8en o& !rakeAs &irst sstem )re( to ;$4 million$ B8t ea annel, ea station, (e t8ne to as an eCeptionall narro( &reK8en ran)e$ ere are no kno(n proesses o8t amon) te stars and )alaCies tat an )enerate s8 sarp radio lines$ I& (e pik 8p antin) &allin) into so narro( a annel, it m8st, (e tink, be a token o& intelli)ene and tenolo)$ *atAs more, te Eart t8rnsG(i means tat an distant radio so8re (ill a'e a siable apparent motion, like te risin) and settin) o& te stars$ >8st as te stead tone o& a arAs orn dips as it dri'es b, so an a8tenti eCtraterrestrial radio so8re (ill eCibit a stead dri&t in &reK8en d8e to te EartAs rotation$ In ontrast, an so8re o& radio inter&erene at te EartAs s8r&ae (ill be rotatin) at te same speed as te E reei'er$ EAs listenin) &reK8enies are ontin8o8sl an)ed to ompensate &or te EartAs rotation, so tat an narro(band Si)nals &rom te sk (ill al(as appear in a sin)le annel$ B8t an radio inter&erene do(n ere on Eart (ill )i'e itsel& a(a b rain) tro8) adHaent annels$
171
e E radio telesope at ar'ard, assa8setts, is "6 meters =;4 &eet< in diameter$ Ea da, as te Eart rotates te telesope beneat te sk, a s(at o& stars narro(er tan te &8ll moon is s(ept o8t and eCamined$ NeCt da, itAs an adHaent s(at$ 2'er a ear, all o& te nortern sk and part o& te so8tern is obser'ed$ n idential sstem, also sponsored b e lanetar Soiet, is in operation H8st o8tside B8enos ires, r)entina, to eCamine te so8tern sk$ So to)eter te t(o E sstems a'e been eCplorin) te entire sk$ e radio telesope, )ra'itationall )l8ed to te spinnin) Eart, looks at an )i'en star &or abo8t t(o min8 tes$ en itAs on to te neCt$ ;$4 million annels so8nds like a lot, b8t remember, ea annel is 'er narro($ ll o& tem to)eter onstit8te onl a &e( parts in 100,000 o& te a'ailable radio spetr8m$ So (e a'e to park o8r ;$4 milli on annels some(ere in te radio spetr8m &or ea ear o& obser'ation, near some &reK8en tat an alien i'iliation, kno(in) notin) abo8t 8s, mi)t ne'erteless onl8de (eAre listenin) to$ dro)en is b &ar te most ab8ndant kind o& atom in te ni'erse$ ItAs distrib8ted in lo8ds and as di&&8se )as tro8)o8t interstellar spae$ *en it aK8ires ener), it releases some o& it b )i'in) o&& radio (a'es at a preise &reK8en o& 14"0$40575176; me)aert$ =2ne ert means te rest and tro8) o& a (a'e arri'in) at o8r detetion instr8ment ea seond$ So 14"0 me)aert means 1$4"0 ;illion (a'es enterin) o8r detetor e'er seond$ Sine te (a'elen)t o& li)t is H8st te speed o& li)t di'ided b te &reK8en o& te (a'e, 14"0 me)aert orresponds to a (a'elen)t o& "1 entimeters$< adio astronomers an(ere in te /alaC (ill be st8din) te ni'erse at 14"0 me)aert and an antiipate tat oter radio astronomers, no matter o( di&&erent te ma look, (ill do te same$ ItAs as i& someone told o8 tat tereAs onl one station on o8r ome radio setAs &reK8en band, b8t tat no one kno(s its &reK8en$ 2 es, one oter tin): o8r setAs &reK8en dial, kit its tin marker o8 adH8st b t8rnin) a knob, appens to rea &rom te Eart to te oon$ o sear sstematiall tro8) tis 'ast radio spetr8m, patientl t8rnin) te knob, is )oin) to be 'er time-ons8min)$ o8r problem is to set te dial orretl &rom te be)innin), to oose te ri)t &reK8en$ I& o8 an orretl )8ess (at &reK8enies tat eCtraterrestrials are broadastin) to 8s onGte ma)i &reK8eniesGten o8 an sa'e o8rsel& m8 time and tro8ble$ ese are te sorts o& reasons tat (e &irst listened, as !rake did, at &reK8enies near 14"0 me)aert, te dro)en ma)i &reK8en$ oro(it and I a'e p8blised detailed res8lts &rom &i'e ears o& &8ll-time searin) (it roHet E and t(o ears o& &ollo(-8p$ *e anAt report tat (e &o8nd a si)nal &rom alien bein)s$ B8t (e did &ind sometin) p8lin), sometin) tat &or me in K8iet moments, e'er no( and ten, raises )oose b8mps: 2& o8rse, tereAs a bak)ro8nd le'el o& radio noise &rom EartGradio and tele'ision stations, airra&t, portable telepones, nearb and more distant spaera&t$ lso, as (it all radio reei'ers, te lon)er o8 (ait, te more likel it is tat tereAll be some random &l8t8ation in te eletronis so stron) tat it )enerates a sp8rio8s si)nal$ So (e i)nore antin) tat isnAt m8 lo8der tan te bak)ro8nd$ n stron) narro(-band si)nal tat remains in a sin)le annel (e take 'er serio8sl$ s it lo)s in te data, E a8tomatiall tells te 8man operators to pa attention to ertain si)nals$ 17"
2'er &i'e ears (e made some 60 trillion obser'ations at 'ario8s &reK8enies, (ile eCaminin) te entire aessible sk$ &e( doen si)nals s8r'i'e te 8llin)$ ese are s8bHeted to &8rter sr8tin, and almost all o& tem are reHeted-&or eCample, bea8se an error as been &o8nd b &a8lt-detetion miroproessors tat eCamine te si)nal-detetion miroproessors$ *atAs le&tGte stron)est andidate si)nals a&ter tree s8r'es o& te skGare 11 e'ents$ e satis& all b8t one o& o8r riteria &or a )en8ine alien si)nal$ B8t te one &ailed riterion is s8premel important: #eri&iabilit$ *eA'e ne'er been able to &ind an o& tem a)ain$ *e look bak at tat part o& te sk tree min8tes later and tereAs notin) tere$ *e look a)ain te &ollo(in) da: notin)$ ECamine it a ear later, or se'en ears later, and still tereAs notin)$ It seems 8nlikel tat e'er si)nal (e )et &rom alien i'iliations (o8ld t8rn itsel& o&& a o8ple o& min8tes a&ter (e be)in listenin), and ne'er repeat$ =o( (o8ld te kno( (eAre pain) attentionD< B8t, H8st possibl, tis is te e&&et o& t(inklin)$ Stars t(inkle bea8se parels o& t8rb8lent air are mo'in) aross te line o& si)t bet(een te star and 8s$ Sometimes tese air parels at as a lens and a8se te li)t ras &rom a )i'en star to on'er)e a little, makin) it momentaril bri)ter$ Similarl, astronomial radio so8res ma also t(inkleGo(in) to lo8ds o& eletriall ar)ed =or ionied< )as in te )reat near-'a88m bet(een te stars$ *e obser'e tis ro8tinel (it p8lsars$ Ima)ine a radio si)nal tatAs a little belo( te stren)t tat (e o8ld oter(ise detet on Eart$ 2asionall te si)nal (ill b ane be temporaril &o8sed, ampli&ied, and bro8)t (itin te detetabilit ran)e o& o8r radio telesopes$ e interestin) tin) is tat te li&etimes o& s8 bri)tenin), predited &rom te psis o& te interstellar )as, are a &e( min8tesGand te ane o& reaK8irin) te si)nal is small$ *e so8ld reall be pointin) steadil at tese oordinates in te sk, (atin) tem &or monts$ !espite te &at tat none o& tese si)nals repeats, tereAs an additional &at abo8t tem tat, e'er time I tink abo8t it, sends a ill do(n m spine: ; o& te 11 best andidate si)nals lie in or near te plane o& te ilk *a /alaC$ e &i'e stron)est are in te onstellations +assiopeia, onoeros, dra, and t(o in Sa)ittari8sGin te approCimate diretion o& te enter o& te /alaC$ e ilk *a is a &lat, (eel-like olletion o& )as and d8st and stars$ Its &latness is ( (e see it as a band o& di&&8se li)t aross te ni)t sk$ atAs (ere almost all te stars in o8r )alaC are$ I& o8r andidate si)nals reall (ere radio inter&erene &rom Eart or some 8ndeteted )lit in te detetion eletronis, (e so8ldnAt see tem pre&erentiall (en (eAre pointin) at te ilk *a$ B8t mabe (e ad an espeiall 8nl8k and misleadin) r8n o& statistis$ e probabilit tat tis orrelation (it te )alati plane is d8e merel to ane is less tan al& a perent$ Ima)ine a (all-sie map o& te sk, ran)in) &rom te Nort Star at te top to te &ainter stars to(ard (i te EartAs so8t pole points at te bottom$ Snakin) aross tis (all map are te irre)8lar bo8ndaries o& te ilk *a$ No( s8ppose tat o8 (ere blind&olded and asked to tro( &i'e darts at random at te map =(it m8 o& te so8tern sk, inaessible &rom assa8setts, delared o&& limits<$ o8Ad a'e to tro( te set o& &i'e darts more tan "00 times be&ore, b aident, o8 )ot tem to &all as losel (itin te preints o& te ilk *a as te
173
&i'e stron)est E si)nals did$ *ito8t repeatable si)nals, to8), tereAs no (a (e an onl8de tat (eA'e at8all &o8nd eCtraterrestrial intelli)ene$ 2r mabe te e'ents (eA'e &o8nd are a8sed b some ne( kind o& astropsial penomenon, sometin) tat nobod as to8)t o& et, b (i not i'iliations, b8t stars or )as lo8ds =or sometin)< tat do lie in te plane o& te ilk *a emit stron) si)nals in ba&&lin)l narro( &reK8en bands$ .etAs permit o8rsel'es, to8), a moment o& eCtra'a)ant spe8lation$ .etAs ima)ine tat all o8r s8r'i'in) e'ents are in &at d8e to radio beaons o& oter i'iliations$ en (e an estimate G&rom o( little time (eA'e spent (atin) ea piee o& skGo( man s8 transmitters tere are in te entire ilk *a$ e ans(er is sometin) approain) a million$ I& randoml stre(n tro8) spae, te nearest o& tem (o8ld be a &e( 8ndred li)t ears a(a, too &ar &or tem to a'e piked 8p o8r o(n # or radar si)nals et$ e (o8ld not kno( &or anoter &e( ent8ries tat a tenial i'iliation as emer)ed on Eart$ e /alaC (o8ld be p8lsin) (it li&e and intelli)ene, b8tG8nless teAre b8sil eCplorin) 8)e n8mbers o& obs8re star sstems G(oll obli'io8s o& (at as been appenin) do(n ere latel$ &e( ent8ries &rom no(, a&ter te do ear &rom 8s, tin)s mi)t )et 'er interestin)$ %ort8natel, (eAd a'e man )enerations to prepare$ I&, on te oter and, none o& o8r andidate si)nals is an a8tenti alien radio beaon, ten (eAre &ored to te onl8sion tat 'er &e( i'iliations are broadastin), mabe none, at least at o8r ma)i &reK8enies and stron)l eno8) &or 8s to ear: +onsider a i'iliation like o8r o(n, b8t (i dediated all its a'ailable po(er =abo8t 10 trillion (atts< to broadastin) a beaon si)nal at one o& o8r ma)i &reK8enies and to all diretions in spae$ e E res8lts (o8ld ten impl tat tere are no s8 i'iliations o8t to "5 li)t-earsGa 'ol8me tat enompasses peraps a doen S8n-like stars$ is is not a 'er strin)ent limit$ I&, in ontrast, tat i'iliation (ere broadastin) diretl at o8r position in spae, 8sin) an antenna no more ad'aned tan te reibo 2bser'ator, ten i& E as &o8nd notin), it &ollo(s tat tere are no s8 i'iliations an(ere in te ilk *a /alaC Go8t o& 400 billion stars, not one$ B8t e'en ass8min) te (o8ld (ant to, o( (o8ld te kno( to transmit in o8r diretionD No( onsider, at te opposite tenolo)ial eCtreme, a 'er ad'aned i'iliation omnidiretionall and eCtra'a)antl broadastin) at a po(er le'el 10 trillion times )reater =10"6 (atts, te entire ener) o8tp8t o& a star like te S8n<$ en, i& te E res8lts are ne)ati'e, (e an onl8de not onl tat tere are no s8 i'iliations in te ilk *a, b8t none o8t to 70 million li)t-earsGnone in 31, te nearest )alaC like o8r o(n, none in 33, or te %ornaC sstem, or ;1, or te *irlpool Neb8la, or +enta8r8s , or te #ir)o l8ster o& )alaCies, or te nearest Se&ert )alaCies? none amon) an o& te 8ndred trillion stars in to8sands o& nearb )alaCies$ Stake tro8) its eart or not, te )eoentri oneit stirs a)ain$ 2& o8rse, it mi)t be a token not o& intelli)ene b8t o& st8pidit to po8r so m8 ener) into interstellar =and inter)alati< omm8niation$ eraps te a'e )ood reasons not to ail all omers$ 2r peraps te donAt are abo8t i'iliations as bak(ard as (e are$ B8t stillGnot one i'iliation in a 8ndred trillion stars broadastin) (it s8 po(er on s8 a &reK8enD I&
174
te E res8lts are ne)ati'e, (e a'e set an instr8ti'e limitGb8t (eter on te ab8ndane o& 'er ad'aned i'iliations or teir omm8niations strate) (e a'e no (a o& kno(in)$ E'en i& E as &o8nd notin), a broad middle ran)e remains openGo& ab8ndant i'iliations, more ad'aned tan (e and broadastin) omnidiretionall at ma)i &reK8enies$ *e (o8ld not a'e eard &rom tem et$
ON OCTOBER !, **!—a8spiio8sl
or oter(ise te 500t anni'ersar o& te diso'er o&
meria b +ristoper +ol8mb8sGNS t8rned on i" ne( SEI pro )ram$ t a radio telesope in te oHa' e !esert, a sear (as initi ated intended to o'er te entire sk sstematiallGlike E, makin) no )8esses abo8t (i stars are more likel, b8t )reatl eCpandin) te &reK8en o'era)e$ t te reibo 2bser'ator, an e'en more sensiti'e NS st8d be)an tat onentrated on promisin) nearb star sstems$ *en &8ll operational, te NS seares (o8ld a'e been able to detet m8 &ainter si)nals tan E, and look &or kinds o& si)nals tat E o8ld not$ e E eCperiene re'eals a tiket o& bak)ro8nd stati and radio inter&erene$ T8ik reobser' ation and on&irmation o& te si)nalGspeiall at oter, independent radio telesopesGis te ke to bein) s8re$ oro(it and I )a'e NS sientists te oordinates o& o8r &leetin) and eni)mati e'ents$ eraps te (o8ld be able to on&irm and lari& o8r res8lts$ e NS pro)ram (as also de'elopin) ne( tenolo), stim8latin) ideas, and eCitin) soolildren$ In te ees o& man it (as (ell (ort te Y10 million a ear bein) spent on it$ B8t almost eCatl a ear a&ter a8toriin) it, +on)ress p8lled te pl8) on NSAs SEI pro)ram$ It ost too m8, te said$ e post-+old *ar $S$ de&ense b8d)et is some 30,000 times lar)er$ e ie& ar)8ment o& te prinipal opponent o& te NS SEI pro)ramGSenator iard Bran o& Ne'adaG(as tis Q&rom te #ongreional e7or&or September "", 1993R: So &ar, te NS SEI ro)ram as &o8nd notin)$ In &at, all te deades o& SEI resear a'e &o8nd no on&irmable si)ns o& eCtraterrestrial li&e$ E'en (it te 8rrent NS 'ersion o& SEI, I do not tink man o& its sientists (o8ld be (illin) to )8arantee tat (e are likel to see an tan)ible res8lts in te Q&oreseeableR &8t8re $ $ $ Sienti&i resear rarel, i& e'er, o&&ers )8arantees o& s8essGand I 8nderstand tat Gand te &8ll bene&its o& s8 resear are o&ten 8nkno(n 8ntil 'er late in te proess$ nd I aept tat, as (ell$ In te ase o& SEI, o(e'er, te anes o& s8ess are so remote, and te likel bene&its o& te pro)ram are so limited, tat tere is little H8sti&iation &or 1" million taCpaer dollars to be eCpended &or tis pro)ram$ B8t o(, be&ore (e a'e &o8nd eCtraterrestrial intelli)ene, an (e )8arantee tat (e (ill &ind itD o(, on te oter and, an (e kno( tat te anes o& s8ess are remoteD nd i&
175
(e &ind eCtraterrestrial intelli)ene, are te bene&its reall likel to be so limitedD s in all )reat eCplorator 'ent8res, (e do not kno( (at (e (ill &ind and (e donAt kno( te probabilit o& &indin) it$ I& (e did, (e (o8ld not a'e to look$ SEI is one o& tose sear pro)rams irritatin) to tose (o (ant (ell-de&ined ostbene&it ratios$ *eter EI an be &o8nd? o( lon) it (o8ld take to &ind it? and (at it (o8ld ost to do so are all 8nkno(n$ e bene&its mi)t be enormo8s, b8t (e anAt reall be s8re o& tat eiter$ It (o8ld o& o8rse be &oolis to spend a maHor &ration o& te national treas8re on s8 'ent8res, b8t I (onder i& i'iliations annot be alibrated b (eter te pa ome attention to trin) to sol'e te )reat problems$ !espite tese setbaks, a dediated band o& sientists and en)ineers, entered at te SEI Instit8te in alo lto, +ali&ornia, as deided to )o aead, )o'ernment or no )o'ernment$ NS as )i'en tem permission to 8se te eK8ipment alread paid &or? aptains o& te eletronis ind8str a'e donated a &e( million dollars? at least one appropriate radio telesope is a'ailable? and te initial sta)es o& tis )randest o& all SEI pro)rams is on trak$ I& it an demonstrate tat a 8se&8l sk s8r'e is possible (ito8t bein) s(amped b bak)ro8nd noiseGand espeiall i&, as is 'er likel &rom te E eCperiene, tere are 8neCplained andidate si)nals-peraps +on)ress (ill an)e its mind one more and &8nd te proHet$ ean(ile, a8l oro(it as ome 8p (it a ne( pro)ramGdi&&erent &rom E, di&&erent &rom (at NS (as doin)Galled BE$ BE stands &or Billion-annel ECtraerrestrial ssa$ It ombines narro(-band sensiti'it, (ide &reK8en o'era)e, and a le'er (a to 'eri& si)nals as teAre deteted$ I& e lanetar Soiet an &ind te additional s8pport, tis sstemGm8 eaper tan te &ormer NS pro)ramGso8ld be on te air soon$
WOUL D I LIKE TO BELIEV E
tat (it E (eA'e deteted transmissions &rom oter
i'iliations o8t tere in te dark, sprinkled tro8) te 'ast ilk *a /alaCD o8 bet$ &ter deades o& (onderin) and st8din) tis problem, o& o8rse I (o8ld$ o me, s8 a diso'er (o8ld be trillin)$ It (o8ld an)e e'ertin)$ *e (o8ld be earin) &rom oter bein)s, independentl e'ol'ed o'er billions o& ears, 'ie(in) te ni'erse peraps 'er di&&erentl, probabl m8 smarter, ertainl not 8man$ o( m8 do te kno( tat (e donAtD %or me, no si)nals, no one allin) o8t to 8s is a depressin) prospet$ +omplete silene, said >ean->aK8es o8ssea8 in a di&&erent onteCt, ind8es melanol? it is an ima)e o& deat$ B8t IAm (it enr !a'id orea8: * so8ld I &eel lonelD Is not o8r planet in te ilk *aD e realiation tat s8 bein)s eCist and tat, as te e'ol8tionar proess reK8ires, te m8st be 'er di&&erent &rom 8s, (o8ld a'e a strikin) impliation: *ate'er di&&erenes di'ide 8s do(n ere on Eart are tri'ial ompared to te di&&erenes bet(een an o& 8s and an o& tem$ abe itAs a lon) sot, b8t te diso'er o& eCtraterrestrial intelli)ene mi)t pla a role in 8ni&in) o8r sK8abblin) and di'ided planet$ It (o8ld be te last o& te /reat !emotions, a rite o& passa)e &or o8r speies and a trans&ormin) e'ent in te anient K8est to diso'er o8r plae in te ni'erse$ 176
In o8r &asination (it SEI, (e mi)t be tempted, e'en (ito8t )ood e'idene, to s88mb to belie& b8t tis (o8ld be sel&-ind8l)ent and &oolis$ *e m8st s8rrender o8r skeptiism onl in te &ae o& rok-solid e'idene$ Siene demands a tolerane &or ambi)8it$ *ere (e are i)norant, (e (itold belie&$ *ate'er annoane te 8nertaint en)enders ser'es a i)er p8rpose: It dri'es 8s to a8m8late better data$ is attit8de is te di&&erene bet(een siene and so m8 else$ Siene o&&ers little in te (a o& eap trills$ e standards o& e'idene are strit$ B8t (en &ollo(ed te allo( 8s to see &ar, ill8minatin) e'en a )reat darkness$
177
+
E
"1
TO THE SKY!
e stairs o& te sk are let do(n &or im tat e ma asend tereon to ea'en$ 2 )ods, p8t o8r arms 8nder te kin): raise im, li&t im to te sk$ o te skF o te skF GN %2 !E! 2 =E/, +$ "600 B$+$<
Wen m )randparents (ere ildren, te eletri li)t, te a8tomobile, te airplane, and te radio (ere St8pe&in) tenolo)ial ad'anes, te (onders o& te a)e$ o8 mi)t ear (ild stories abo8t tem, b8t o8 o8ld not &ind a sin)le eCemplar in tat little 'illa)e in 8stria8n)ar, near te banks o& te ri'er B8)$ B8t in tat same time, aro8nd te t8rn o& te last ent8r, tere (ere t(o men (o &oresa( oter, &ar more ambitio8s, in'entionsGonstantin siolko'sk, te teoretiian, a nearl dea& soolteaer in te obs8re 8ssian to(n o& al8)a, and obert /oddard, te en)ineer, a pro&essor at an eK8all obs8re merian olle)e in assa8setts$ e dreamt o& 8sin) rokets to Ho8rne to te planets and te stars$ Step b step, te (orked o8t te &8ndamental psis and man o& te details$ /rad8all, teir maines took sape$ ltimatel, teir dream pro'ed in&etio8s$ In teir time, te 'er idea (as onsidered disrep8table, or e'en a smptom o& some obs8re deran)ement$ /oddard &o8nd tat merel mentionin) a 'oa)e to oter (orlds s8bHeted im to
17;
ridi8le, and e dared not p8blis or e'en dis8ss in p8bli is lon)-term 'ision o& &li)ts to te stars$ s teena)ers, bot ad epipanal 'isions o& spae&li)t tat ne'er le&t tem$ I still a'e dreams in (i I &l 8p to te stars in m maine, siolko'sk (rote in middle a)e$ It is di&&i8lt to (ork all on o8r o(n &or man ears, in ad'erse onditions (ito8t a )leam o& ope, (ito8t an elp$ an o& is ontemporaries to8)t e (as tr8l mad$ ose (o kne( psis better tan siolko'sk and /oddardGinl8din) /e e< ,ork /ime in a dismissi'e editorial not retrated 8ntil te e'e o& Apollo 11Ginsisted tat rokets o8ld not (ork in a 'a88m, tat te oon and te planets (ere &ore'er beond 8man rea$ )eneration later, inspired b siolko'sk and /oddard, *erner 'on Bra8n (as onstr8tin) te &irst roket apable o& reain) te ed)e o& spae, te #-"$ B8t in one o& tose ironies (it (i te t(entiet ent8r is replete, 'on Bra8n (as b8ildin) it &or te NaisGas an instr8ment o& indisriminate sla8)ter o& i'ilians, as a 'en)eane (eapon &or itler, te roket &atories sta&&ed (it sla'e labor, 8ntold 8man s8&&erin) eCated in te onstr8tion o& e'er booster, and 'on Bra8n imsel& made an o&&ier in te SS$ e (as aimin) at te oon, e Hoked 8nsel&onsio8sl, b8t it .ondon instead$ noter )eneration later, b8ildin) on te (ork o& siolko'sk and /oddard, eCtendin) 'on Bra8nAs tenolo)ial )eni8s, (e (ere 8p tere in spae, silentl ir8mna'i)atin) te Eart, treadin) te anient and desolate l8nar s8r&ae$ 28r mainesGinreasin)l ompetent and a8tonomo8sG(ere spreadin) tro8) te Solar Sstem, diso'erin) ne( (orlds, eCaminin) tem losel, searin) &or li&e, omparin) tem (it Eart$ is is one reason tat in te lon) astronomial perspeti'e tere is sometin) tr8l epoal abo8t no(G(i (e an de&ine as te &e( ent8ries entered on te ear o8Are readin) tis book$ nd tereAs a seond reason: is is te &irst moment in te istor o& o8r planet (en an speies, b its o(n 'ol8ntar ations, as beome a dan)er to itsel&Gas (ell as to 'ast n8mbers o& oters$ .et me reo8nt te (as:
Z *eA'e been b8rnin) &oss il &8els &or 8ndred s o& to8sands o& ears$ B te 1960s, tere (ere so man o& 8s b8rnin) (ood, oal, oil, and nat8ral )as on so lar)e a sale, tat
Z
Z
Z
Z
sientists be)anslo(l to (orr abo8tinto te p8bli inreasin) )reeno8se e&&et? te dan)ers o& )lobal (armin) be)an slippin) onsio8sness$ +%+s (ere in'ented in te 19"0s and 1930s? in 1974 te (e re diso'ered to attak te proteti'e oone laer$ %i&teen ears later a (orld(ide ban on teir prod8tion (as )oin) into e&&et$ N8lear (eapons (ere in'ented in 1945$ It took 8ntil 19;3 be&ore te )lobal onseK8enes o& termon8lear (ar (ere 8nderstood$ B 199", lar)e n8mbers o& (areads (ere bein) dismantled$ e &irst asteroid (as diso'ered in 1;01$ ore or less serio8s proposals to mo'e tem aro8nd (ere &loated be)innin) in te 19;0s$ eo)nition o& te potential dan)ers o& asteroid de&letion tenolo) &ollo(ed sortl a&ter$ Biolo)ial (ar&are as been (it 8s &or ent8ries, b8t its deadl mat in) (it mole8lar biolo) as o8rred onl latel$
179
Z *e 8mans a'e alread preip itated eCtintions o& speies on a sale 8npreedented sine te end o& te +retaeo8s eriod$ B8t onl in te last deade as te ma)nit8de o& tese eCtintions beome lear, and te possibilit raised tat in o8r i)norane o& te interrelations o& li&e on Eart (e ma be endan)erin) o8r o(n &8t8re$
.ook at te dates on tis list and onsider te ran)e o& ne( tenolo)ies 8rrentl 8nder de'elopment$ Is it not likel tat oter dan)ers o& o8r o(n makin) are et to be diso'ered, some peraps e'en more serio8sD In te littered &ield o& disredited sel&-on)rat8lator a8'inisms, tere is onl one tat seems to old 8p, one sense in (i (e are speial: !8e to o8r o(n ations or inations, and te mis8se o& o8r tenolo), (e li'e at an eCtraordinar moment, &or te Eart at leastGte &irst time tat a speies as beome able to (ipe itsel& o8t$ B8t tis is also, (e ma note, te &irst time tat a speies as beome able to Ho8rne to te planets and te stars$ e t(o times, bro8)t abo8t b te same tenolo), oinideGa &e( ent8ries in te istor o& a 4$5-billionear-old planet$ I& o8 (ere someo( dropped do(n on te Eart randoml at an moment in te past =or &8t8re<, te ane o& arri'in) at tis ritial moment (o8ld be less tan 1 in 10 million$ 28r le'era)e on te &8t8re is i) H8st no($ It mi)t be a &amiliar pro)ression, transpirin) on man (orldsGa planet, ne(l &ormed, plaidl re'ol'es aro8nd its star? li&e slo(l &orms? a kaleidosopi proession o& reat8res e'ol'es? intelli)ene emer)es (i, at least 8p to a point, on&ers enormo8s s8r'i'al 'al8e? and ten tenolo) is in'ented$ It da(ns on tem tat tere are s8 tin)s as la(s o& Nat8re, tat tese la(s an be re'ealed b eCperiment, and tat kno(led)e o& tese la(s an be made bot to sa'e and to take li'es, bot on 8npreedented sales$ Siene, te reo)nie, )rants immense po(ers$ In a &las, te reate (orld-alterin) ontri'anes$ Some planetar i'iliations see teir (a tro8), plae limits on (at ma and (at m8st not be done, and sa&el pass tro8) te time o& perils$ 2ters are not so l8k or so pr8dent, peris$ Sine, in te lon) r8n, e'er planetar soiet (ill be endan)ered b impats &rom spae, e'er s8r'i'in) i'iliation is obli)ed to beome spae&arin)G-not bea8se o& eCplorator or romanti eal, b8t &or te most pratial reason ima)inable: stain) ali'e$ nd one o8Are o8t tere in spae &or ent8ries and millennia, mo'in) little (orlds aro8nd and en)ineerin) planets, o8r speies as been pried loose1&rom its radle$ I& te eCist, man oter i'iliations (ill e'ent8all 'ent8re &ar &rom ome$
1
i)t a planetar i'iliation (i as s8r'i'ed its adolesene (is to eno8ra)e oters str8))lin) (it "eir emer)in) tenolo)iesD eraps te (o8ld make speial e&&orts to broadast ne(s o& teir eCistene, te tri8mpant anno8nement tat itAs possible to a'oid sel&-anniilation$ 2r (o8ld te at &irst be 'er a8tio8sD a'in) a'oided atastropes o& teir o(n makin), peraps te (o8ld &ear )i'in) a(a kno(led)e o& teir eCistene, lest some oter, 8nkno(n, a))randiin) i'iliation o8t tere in te dark is lookin) &or &e;enraum or sla'erin) to p8t do(n te potential ompetition$ at mi)t be a reason &or 8s to eCplore nei)borin) star sstems, b8t disreetl$ abe te (o8ld be silent &or anoter reason: bea8se broadastin) te eCistene o& an ad'aned i'iliation mi)t eno8ra)e emer)in) i'iliations to do less tan teir best e&&orts to sa&e)8ard teir &8t8reG opin) instead tat someone (ill ome o8t o& te dark and sa'e tem &rom temsel'es$
1;0
A MEAN S HA S BEEN OFFERED o&
estimatin) o( preario8s o8r ir8mstanes areG
remarkabl, (ito8t in an (a addressin) te nat8re o& te aards$ >$ iard /ott III is an astropsiist at rineton ni'ersit$ e asks 8s to adopt a )eneralied +opernian priniple, sometin) IA'e desribed else(ere as te riniple o& ediorit$ +anes are tat (e do not li'e in a tr8l eCtraordinar time$ ardl anone e'er did$ e probabilit is i) tat (eAre born, li'e o8t o8r das, and die some(ere in te broad middle ran)e o& te li&etime o& o8r speies =or i'iliation, or nation<$ lmost ertainl, /ott sas, (e do not li'e in &irst or last times$ So i& o8r speies is 'er o8n), it &ollo(s tat itAs 8nlikel to last lon)Gbea8se i& it
proportionall speakin), so near te be)innin)$ *at ten is te proHeted lon)e'it o& o8r speiesD /ott onl8des, at te 97$5 perent on&idene le'el, tat tere (ill be 8mans &or no more tan ; million ears$ atAs is 8pper limit, abo8t te same as te a'era)e li&etime o& man mammalian speies$ In tat ase, o8r tenolo) neiter arms nor elps$ B8t /ottAs lo(er limit, (it te same laimed reliabilit, is onl 1" ears$ e (ill not )i'e o8 40-to-1 odds tat 8mans (ill still be aro8nd b te time babies no( ali'e beome teena)ers$ In e'erda li&e (e tr 'er ard not to take risks so lar)e, not to board airplanes, sa, (it 1 ane in 40 o& rasin)$ *e (ill a)ree to s8r)er in (i 95 perent o& patients s8r'i'e onl i& o8r disease as a )reater tan 5 perent ane o& killin) 8s$ ere 40-to-1 odds on o8r speies s8r'i'in) anoter 1" ears *o8ld be, i& 'alid, a a8se &or s8preme onern$ I& /ott is ri)t, not onl ma (e ne'er be o8t amon) te stars? tereAs a &air ane (e ma not be aro8nd lon) eno8) e'en to make te &irst &oot&all on anoter planet$ o me, tis ar)8ment as a stran)e, 'aporis K8alit$ no(in) notin) abo8t o8r speies eCept o( old it is, (e make n8merial estimates, laimed to be i)l reliable, abo8t its &8t8re prospets$ o(D *e )o (it te (inners$ ose (o a'e been aro8nd are likel to sta aro8nd$ Ne(omers tend to disappear$ e onl ass8mption is te K8ite pla8sible one tat tere is notin) speial abo8t te moment at (i (e inK8ire into te matter$ So ( is te ar)8ment 8nsatis&in)D Is it H8st tat (e are appalled b its impliationsD Sometin) like te riniple o& ediorit m8st a'e 'er broad appliabilit$ B8t (e are not so i)norant as to ima)ine tat e'ertin) is mediore$ ere is sometin) speial abo8t o8r timeGnot H8st te temporal a8'inism tat tose (o reside in an epo do8btless &eel, b8t sometin), as o8tlined abo'e, learl 8niK8e and stritl rele'ant to o8r speiesA &8t8re anes: is is te &irst time tat =a< o8r eCponentiatin) tenolo) as reaed te preipie o& sel&destr8tion, b8t also te &irst time tat =b< (e an postpone or a'oid destr8tion b )oin) some(ere else, some(ere o&& te Eart$ ese t(o l8sters o& apabilities, =a< and =b<, make o8r time eCtraordinar in diretl ontraditor (asG(i bot =a< stren)ten and =b< (eaken /ottAs ar)8ment$ I donAt kno( o( to predit (eter te ne( destr8ti'e tenolo)ies (ill asten, more tan te ne( spae&li)t tenolo)ies (ill dela, 8man eCtintion$ B8t sine ne'er be&ore a'e (e ontri'ed te means o& anniilatin) o8rsel'es, and ne'er be&ore a'e ( e de'eloped te tenolo) &or settlin) oter (orlds, I tink a ompellin) ase an be made tat o8r time is eCtraordinar preisel in te onteCt o& /ottAs ar)8ment$ I& tis is tr8e, it si)ni&iantl inreases te mar)in o& 1;1
error in s8 estimates o& &8t8re lon)e'it$ e (orst is (orse, and te best better: 28r sortterm prospets are e'en bleaker andGi& (e an s8r'i'e te sort-termGo8r lon)-term anes e'en bri)ter tan /ott al8lates$ B8t te &ormer is no more a8se &or despair tan te latter is &or omplaen$ Notin) &ores 8s to be passi'e obser'ers, l8kin) in disma as o8r destin ineCorabl (orks itsel& o8t$ I& (e annot K8ite seie &ate b te nek, peraps (e an misdiret it, or molli& it, or esape it$ 2& o8rse (e m8st keep o8r planet abitableGnot on a leis8rel timesale o& ent8ries or millennia, b8t 8r)entl, on a timesale o& deades or e'en ears$ is (ill in'ol'e an)es in )o'ernment, in ind8str, in etis, in eonomis, and in reli)ion$ *eA'e ne'er done s8 a tin) be&ore, ertainl not on a )lobal sale$ It ma be too di&&i8lt &or 8s$ !an)ero8s tenolo)ies ma be too (idespread$ +orr8ption ma be too per'asi'e$ oo man leaders ma be &o8sed on te sort term rater tan te lon)$ ere ma be too man K8arrelin) etni )ro8ps, nation-states, and ideolo)ies &or te ri)t kind o& )lobal an)e to be instit8ted$ *e ma be too &oolis to perei'e e'en (at te real dan)ers are, or tat m8 o& (at (e ear abo8t tem is determined b tose (it a 'ested interest in minimiin) &8ndamental an)e$ o(e'er, (e 8mans also a'e a istor o& makin) lon)-lastin) soial an)e tat nearl e'erone to8)t impossible$ Sine o8r earliest das, (eA'e (orked not H8st &or o8r o(n ad'anta)e b8t &or o8r ildren and o8r )randildren$ )randparents and parents did so &or me$ *e a'e o&ten, despite o8r di'ersit, despite endemi atreds, p8lled to)eter to &ae a ommon enem$ *e seem, tese das, m8 more (illin) to reo)nie te dan)ers be&ore 8s tan (e (ere e'en a deade a)o$ e ne(l reo)nied dan)ers treaten all o& 8s eK8all$ No one an sa o( it (ill t8rn o8t do(n ere$
THE MOON WAS WHERE te
tree o& immortalit )re( in anient +inese mt$ e tree o&
lon)e'it i& not o& immortalit, it seems, indeed )ro(s on oter (orlds$ I& (e (ere 8p tere amon) te planets, i& tere (ere sel&-s8&&iient 8man omm8nities oil man (orlds, o8r speies (o8ld be ins8lated &rom atastrope$ e depletion o& te 8ltra'iolet-absorbin) sield on one (orld (o8ld, i& antin), be a (arnin) to take speial are o& te sie ld on anoter$ atalsmi impat on one (orld (o8ld likel lea'e all te oters 8nto8ed$ e more o& 8s beond te Eart, te )reater te di'ersit o& (orlds (e inabit, te more 'aried te planetar en)ineerin), te )reater te ran)e o& soietal standards and 'al8esGten te sa&er te 8man speies (ill be$ I& o8 )ro( 8p li'in) 8nder)ro8nd in a (orld (it a 8ndredt o& an Eart )ra'it and blak skies tro8) te portals, o8 a'e a 'er di&&erent set o& pereptions, interests, preH8dies, and predispositions tan someone (o li'es on te s8r&ae o& te ome planet$ .ike(ise i& o8 li'e on te s8r&ae o& ars in te troes o& terra&ormin), or #en8s, or itan$ is strate)G breakin) 8p into man smaller sel&-propa)atin) )ro8ps, ea (it some(at di&&erent stren)ts and onerns, b8t all marked b loal prideGas been (idel emploed in te e'ol8tion o& li&e on Eart, and b o8r o(n anestors in parti8lar$ It ma, in &at, be ke to 8nderstandin) ( (e
1;"
8mans are te (a (e are$
1
is is te seond o& te missin) H8sti&iations &or a permanent
8man presene in spae: to impro'e o8r anes o& s8r'i'in), not H8st te atastropes (e an &oresee, b8t also te ones (e annot$ /ott also ar)8es tat establisin) 8man omm8nities on oter (orlds ma o&&er 8s o8r best ane o& beatin) te odds$ o take o8t tis ins8rane poli is not 'er eCpensi'e, not on te sale on (i (e do tin)s on Eart$ It (o8ld not e'en reK8ire do8blin) te spae b8d)ets o& te present spae&arin) nations =(i, in all ases, are onl a small &ration o& te militar b8d)ets and man oter 'ol8ntar eCpendit8res tat mi)t be onsidered mar)inal or e'en &ri'olo8s<$ *e o8ld soon be settin) 8mans do(n on near-Eart asteroids and establisin) bases on ars$ *e kno( o( to do it, e'en (it present tenolo), in less tan a 8man li&etime$ nd te tenolo)ies (ill K8ikl impro'e$ *e (ill )et better at )oin) into spae$ serio8s e&&ort to send 8mans to oter (orlds is relati'el so ineCpensi'e on a per annum basis tat it annot serio8sl ompete (it 8r)ent soial a)endas on Eart$ I& (e take tis pat, streams o& ima)es &rom oter (orlds (ill be po8rin) do(n on Eart at te speed o& li)t$ #irt8al realit (ill make te ad'ent8re aessible to millions o& sta-on-Earts$ #iario8s partiipation (ill be m8 more real tan at an earlier a)e o& eCploration and diso'er$ nd te more 8lt8res and people it inspires and eCites, te more likel it (ill appen$ B8t b (at ri)t, (e mi)t ask o8rsel'es, do (e inabit, alter, and onK8er oter (orldsD I& anone else (ere li'in) in te Solar Sstem, tis (o8ld be an important K8estion$ I&, to8), tereAs no one else in tis sstem b8t 8s, donAt (e a'e a ri)t to settle itD 2& o8rse, o8r eCploration and omesteadin) so8ld be enli)tened b a respet &or planetar en'ironments and te sienti&i kno(led)e te old$ is is simple pr8dene$ 2& o8rse, eCploration and settlement o8)t to be done eK8itabl and transnationall, b representati'es o& te entire 8man speies$ 28r past olonial istor is not eno8ra)in) in tese re)ards? b8t tis time (e are not moti'ated b )old or spies or sla'es or a eal to on'ert te eaten to te 2ne r8e %ait, as (ere te E8ropean eCplorers o& te &i&teent and siCteent ent8ries$ Indeed, tis is one o& te ie& reasons (eAre eCperienin) s8 intermittent pro)ress, so man &its and starts in te manned spae pro)rams o& all nations$ !espite all te pro'inialisms I omplained abo8t earl in tis book, ere I &ind msel& an 8napolo)eti 8man a8'inist$ I& tere (ere oter li&e in tis solar sstem, it (o8ld be in imminent dan)er bea8se te 8mans are omin)$ In s8 a ase, I mi)t e'en be pers8aded tat sa&e)8ardin) o8r speies b settlin) ertain oter (orlds is o&&set, in part at least, b te dan)er (e (o8ld pose to e'erbod else$ B8t as nearl as (e an tell, so &ar at least, tere is no oter li&e in tis sstem, not one mirobe$ ereAs onl Eartli&e$ In tat ase, on beal& o& Eartli&e, I 8r)e tat, (it &8ll kno(led)e o& o8r limitations, (e 'astl inrease o8r kno(led)e o& te Solar Sstem and ten be)in to settle oter (orlds$ ese are te missin) pratial ar)8ments: sa&e)8ardin) Ate Eart &rom oter(ise ine'itable atastropi impats and ed)in) o8r bets on te man oter treats, kno(n and 8nkno(n, to te en'ironment tat s8stains 8s$ *ito8t tese ar)8ments, a ompellin) ase &or sendin) 8mans to 1
+&$ Sao< o orgo""en An7e"or= A Sear7 or :o :e Are , b +arl Sa)an and nn !r8an =Ne( ork: andom o8se, 199"<$
1;3
ars and else(ere mi)t be lakin)$ B8t (it temGand te b8ttressin) ar)8ments in'ol'in) siene, ed8ation, perspeti'e, and opeGI tink a stron) ase an be made$ I& o8r lon)-term s8r'i'al is at stake, (e a'e a basi responsibilit to o8r speies 'ent8re to oter (orlds$ Sailors on a bealmed sea, (e sense te stirrin) o& a breee$
C
H
A
P
T
E
R
22
I2EIN/ 2/ E I. * I s(ear b te selters o& te stars =a mi)t oat, i& o8 b8t kne( it< $ $ $ GE TAN, S 56 =7 +EN<
2& o8rse, it is stran)e to inabit te eart no lon)er,
1;4
o )i'e 8p 8stoms one barel ad time to learn $ $ $ GINE I I.E, E %IS E.E/ =19"3<
Te prospet o& salin) ea'en, o& asendin) to te sk, o& alterin) oter (orlds to s8it o8r p8rposesGno matter o( (ell intentioned (e ma beGsets te (arnin) &la)s &lin): *e remember te 8man inlination to(ard o'er(eenin) pride? (e reall o8r &allibilit and misH8d)ments (en presented (it po(er&8l ne( tenolo)ies$ *e reollet te stor o& te o(er o& Babel, a b8ildin) (ose top ma rea 8nto ea'en, and /odAs &ear $so8t o8r speies, tat no( notin) (ill be restrained &rom tem (i te a'e ima)ined to do$ *e ome 8pon salm 15, (i stakes a di'ine laim to oter (orlds: QRe ea'ens are te .ordAs, b8t te Eart lat e )i'en to te ildren o& men$ 2r latoAs retellin) o& te /reek analo)8e o& BabelGte tale o& 2ts and Epialtes$ e (ere mortals (o dared to sale ea'en$ e )ods (ere &aed (it a oie$ So8ld te kill te 8pstart 8mans and anniilate QteirR rae (it t8nderboltsD 2n te one Band, tis (o8ld be te end o& te sari&ies and (orsip (i mien o&&ered te )ods and (i )ods ra'ed$ B8t, on te oter and, te )ods o8ld not s8&&er Qs8R insolene to be 8nrestrained$AA I&, in te lon) term, to8), (e a'e no alternati'e, i& o8r oie reall is man (orlds or none, (e are in need o& oter sorts o& mts o& eno8ra)ement$ e eCist$ an reli)ions, &rom ind8ism to /nosti +ristianit to ormon dotrine, tea tatGas impio8s as it ma so8ndG it is te )oal o& 8mans to ;e7ome )ods$ 2r onsider a stor in te >e(is alm8d le&t o8t o& te Book o& /enesis$ =It is in do8bt&8l aord (it te ao8nt o& te apple, te ree o& no(led)e, te %all, and te eCp8lsion &rom Eden$< In te /arden, /od tells E'e and dam tat e as intentionall le&t te ni'erse 8n&inised$ It is te responsibilit o& 8mans, o'er o8ntless )enerations, to partiipate (it /od in a )lorio8s eCperimentG ompletin) te +reation$ e b8rden o& s8 a responsibilit is ea', espeiall on so (eak and imper&et a speies as o8rs, one (it so 8napp a istor$ Notin) remotel like ompletion an be attempted (ito8t 'astl more kno(led)e tan (e a'e toda$ B8t peraps, i& o8r 'er eCistene is at stake, (e (ill &ind o8rsel'es ble to rise to tis s8preme allen)e$ ALTHOUGH HE DID NOTK8ite
8se an o& te ar)8ments o& te preedin) apter, it (as obert
/oddardAs int8ition tat te na'i)ation o& interplanetar spae m8st be e&&eted to ens8re te ontin8ane o& te rae$ onstantin siolko'sk made a similar H8d)ment: ere are o8ntless planets, like man island Earts $ $ $ an o8pies one o& tem$ B8t ( o8ld e not a'ail imsel& o& oters, and o& te mi)t o& n8mberless s8nsD $ $ $ *en
1;5
te S8n as eCa8sted its ener), it (o8ld be lo)ial to lea'e it and look &or anoter, ne(l kindled, star still in its prime$ is mi)t be done earlier, e s8))ested, lon) be&ore te S8n dies, b ad'ent8ro8s so8ls seekin) &res (orlds to onK8er$ B8t as I retink tis (ole ar)8ment, IAm tro8bled$ Is it too m8 B8k o)ersD !oes it demand an abs8rd on&idene in &8t8re tenolo)D !oes it i)nore m o(n admonitions abo8t 8man &allibilitD S8rel in te sort term itAs biased a)ainst tenolo)iall less-de'eloped nations$ re tere no pratial alternati'es tat a'oid tese pit&allsD ll o8r sel&-in&lited en'ironmental problems, all o8r (eapons o& mass destr8tion are prod8ts o& siene and tenolo)$ So, o8 mi)t sa, letAs H8st bak o&& &rom siene and tenolo)$ .etAs admit tat tese tools are simpl too ot to andle$ .etAs reate a simpler soiet, in (i no matter o( areless or sort-si)ted (e are, (eAre inapable o& alterin) te en'ironment on a )lobal or e'en on a re)ional sale$ .etAs trottle bak to a minimal, a)ri8lt8rall intensi'e tenolo), (it strin)ent ontrols on ne( kno(led)e$ n a8toritarian teora is a tried-and-tr8e (a to en&ore te ontrols$ S8 a (orld 8lt8re is 8nstable, to8), in te lon) r8n i& not te sortGbea8se o& te speed o& tenolo)ial ad'ane$ 8man propensities &or sel&-betterment, en', and ompetition (ill al(as be trobbin) s8bs8r&ae? opport8nities &or sort-term, loal ad'anta)e (ill sooner or later be seied$ nless tere are se'ere onstraints on to8)t and ation, in a &las (eAll be bak to (ere (e are toda$ So ontrolled a soiet m8st )rant )reat po(ers to te elite tat does te ontrollin), in'itin) &la)rant ab8se and e'ent8al rebellion$ ItAs 'er ardGone (eA'e seen te ries, on'enienes, and li&esa'in) mediines tat tenolo) o&&ersGto sK8el 8man in'enti'eness and aK8isiti'eness$ nd (ile s8 a de'ol8tion o& te )lobal i'iliation, (ere it possible, mi)t onei'abl address te problem o& sel&-in&lited tenolo)ial atastrope, it (o8ld also lea'e 8s de&enseless a)ainst e'ent8al asteroidal and ometar impats$ 2r o8 mi)t ima)ine trottlin) bak m8 &8rter, bak to 8nter-)aterer soiet, (ere (e li'e o&& te nat8ral prod8ts o& te land and abandon e'en a)ri8lt8re$ >a'elin, di))in) stik, bo(, arro(, and &ire (o8ld ten be tenolo) eno8)$ B8t te Eart o8ld s8pport at te 'er most a &e( tens o& millions o& 8nter-)aterers$ o( o8ld (e )et do(n to s8 lo( pop8lation le'els (ito8t insti)atin) te 'er atastropes (e are trin) to a'oidD Besides, (e ardl kno( o( to li'e te 8nter-)aterer li&e anmore: *eA'e &or)otten teir 8lt8res, teir skills, teir tool-kits$ *eA'e killed o&& almost all o& tem, and (eA'e destroed m8 o& te en'ironment tat s8stained tem$ ECept &or a tin remnant o& 8s, (e mi)t not be able, e'en i& (e )a'e it i) priorit, to )o bak$ nd a)ain, e'en i& (e o8ld ret8rn, (e (o8ld be elpless be&ore te impat atastrope tat ineCorabl (ill ome$ e alternati'es seem (orse tan r8el: e are ine&&eti'e$ an o& te dan)ers (e &ae indeed arise &rom siene and tenolo)Gb8t, more &8ndamentall, bea8se (e lea'e beome po(er&8l (ito8t beomin) ommens8ratel (ise$ e (orld-alterin) po(ers tat tenolo) as deli'ered into o8r ands no( reK8ire a de)ree o& onsideration and &oresi)t tat as ne'er be&ore been asked o& 8s$
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Siene 8ts t(o (as, o& o8rse? its prod8ts an be 8sed &or bot )ood and e'il$ B8t tereAs no t8rnin) bak &rom siene$ e earl (arnin)s abo8t tenolo)ial dan)ers also ome &rom siene$ e sol8tions ma (ell reK8ire more o& 8s tan H8st a tenolo)ial &iC$ an (ill a'e to beome sienti&iall literate$ *e ma a'e to an)e instit8tions and bea'ior$ B8t o8r problems, (ate'er teir ori)in, annot be sol'ed apart &rom siene$ e tenolo)ies tat treaten 8s and te ir8m'ention o& tose treats bot iss8e &rom te same &ont$ e are rain) nek and nek$ In ontrast, (it 8man soieties on se'eral (orlds, o8r prospets (o8ld be &ar more &a'orable$ 28r port&olio (o8ld be di'ersi&ied$ 28r e))s (o8ld be, almost literall, in man baskets$ Ea soiet (o8ld tend to be pro8d o& te 'irt8es o& its (orld, its planetar en)ineerin), its soial on'entions, its ereditar predispositions$ Neessaril, 8lt8ral di&&erenes (o8ld be erised and eCa))erated$ is di'ersit (o8ld ser'e as a tool o& s8r'i'al$ *en te o&& Eart settlements are better able to &end &or temsel'es, te (ill a'e e'er reason to eno8ra)e tenolo)ial ad'ane, openness o& spirit, and ad'ent8reGe'en i& tose le&t on Eart are obli)ed to prie a8tion, &ear ne( kno(led)e, and instit8te !raonian soial ontrols$ &ter te &irst &e( sel&-s8stainin) omm8nities are establised on oter (orlds, te Eartlin)s mi)t also be able to relaC teir strit8res and li)ten 8p$ e 8mans in spae (o8ld pro'ide tose on Eart (it real protetion a)ainst rare b8t atastropi ollisions b asteroids or omets on ro)8e traHetories$ 2& o8rse, &or tis 'er reason, 8mans in spae (o8ld old te 8pper and in an serio8s disp8te (it tose on Eart$ e prospets o& s8 a time ontrast pro'oati'el (it &oreasts tat te pro)ress o& siene and tenolo) is no( near some asmptoti limit? tat art, literat8re, and m8si are ne'er to approa, m8 less eCeed, te ei)ts o8r speies as, on oasion, alread to8ed? and tat politial li&e on Eart is abo8t to settle into some rok-stable liberal demorati (orld )o'ernment, identi&ied, a&ter e)el, as te end o& istor$ S8 an eCpansion into spae also ontrasts (it a di&&erent b8t like(ise disernible trend in reent timesGto(ard a8toritarianism, ensorsip, etni atred, and a deep s8spiion o& 8riosit and learnin)$ Instead, I tink tat, a&ter some deb8))in), te settlement o& te Solar Sstem presa)es an open-ended era o& dalin) ad'anes in siene and tenolo)? 8lt8ral &lo(erin)? and (ide-ran)in) eCperiments, 8p tere in te sk, in )o'ernment and soial or)aniation$ In more tan one respet, eCplorin) te Solar Sstem and omesteadin) oter (orlds onstit8tes te be)innin), m8 more tan te end, o& istor$ IT'S IMPOSSIBLE, &or
8s 8mans at least, to look into o8r &8t8re, ertainl not ent8ries aead$
No one as e'er done so (it an onsisten and detail$ I ertainl do not ima)ine tat I an$ I a'e, (it some trepidation, )one as &ar as I a'e to tis point in te book, bea8se (e are H8st reo)niin) te tr8l 8npreedented allen)es bro8)t on b o8r tenolo)$ ese allen)es a'e, I tink, oasional strai)t&or(ard impliations, some o& (i IA'e tried brie&l to la o8t$ ere are also less strai)t&or(ard, m8 lon)er-term impliations abo8t (i IAm e'en less on&ident$ Ne'erteless, IAd like to present tem too &or o8r onsideration:
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E'en (en o8r desendants are establised on near-Eart asteroids and ars and te moons o& te o8ter Solar Sstem and te 8iper +omet Belt, it still (onAt be entirel sa&e$ In te lon) r8n, te S8n ma )enerate st8pendo8s -ra and 8ltra'iolet o8tb8rsts? te Solar Sstem (ill enter one o& te 'ast interstellar lo8ds l8rkin) nearb and te planets (ill darken and ool? a so(er o& deadl omets (ill ome roarin) o8t o& te 2ort +lo8d treatenin) i'iliations on man adHaent (orlds? (e (ill reo)nie tat a nearb star is abo8t to beome a s8perno'a$ In te reall lon) r8n, te S8nGon its (a to beomin) a red )iant starG(ill )et bi))er and bri)ter, te Eart (ill be)in to lose its air and (ater to spae, te soil (ill ar, te oeans (ill e'aporate and boil, te roks (ill 'aporie, and o8r planet ma e'en be s(allo(ed 8p into te interior o& te S8n$ %ar &rom bein) made &or 8s, e'ent8all te Solar Sstem (ill beome too dan)ero8s &or 8s$ In te lon) r8n, p8ttin) all o8r e))s in a sin)le stellar basket, no matter o( reliable te Solar Sstem as been latel, ma be too risk$ In te lon) r8n, as siolko'sk and /oddard lon) a)o reo)nied, (e need to lea'e te Solar Sstem$ I& tatAs tr8e &or 8s, o8 mi)t 'er (ell ask, ( isnAt it tr8e &or otersD nd i& it i tr8e &or oters, ( arenAt te ereD ere are man possible ans(ers, inl8din) te ontention tat te a4e ome ereGalto8) te e'idene &or tat is piti&8ll slim$ 2r tere ma be no one else o8t tere, bea8se te destro temsel'es, (it almost no eCeptions, be&ore te aie'e interstellar &li)t? or bea8se in a )alaC o& 400 billion s8ns o8rs is te &irst tenial i'iliation$ more likel eCplanation, I tink, iss8es &rom te simple &at tat spae is 'ast and te stars are &ar apart$ E'en i& tere (ere i'iliations m8 older and more ad'aned tan (eG eCpandin) o8t &rom teir ome (orlds, re(orkin) ne( (orlds, and ten ontin8in) on(ard to oter starsGte (o8ld be 8nlikel, aordin) to al8lations per&ormed b *illiam I$ Ne(man o& +. and me, to be ere$ et$ nd bea8se te speed o& li)t is &inite, te # and radar ne(s tat a tenial i'iliation as arisen on some planet o& te S8n as not reaed tem$ et$ So8ld optimisti estimates pre'ail and one in e'er million stars selters a nearb tenolo)ial i'iliation, and i& as (ell teAre randoml stre(n tro8) te ilk *aG(ere tese pro'isos to oldGten te nearest one, (e reall, (o8ld be a &e( 8ndred li)t-ears distant: at te losest, mabe 100 li)tears, more likel a to8sand li)t-ears-and, o& o8rse, peraps no(ere, no matter o( &ar$ S8ppose te nearest i'iliation on a planet o& anoter star is, sa, "00 li)t-ears a(a$ en, some 150 ears &rom no( teAll be)in to reei'e o8r &eeble post-*orld *ar II tele'ision and radar emission$ *at (ill te make o& itD *it ea passin) ear te si)nal (ill )et lo8der, more interestin), peraps more alarmin)$ E'ent8all, te ma respond: b ret8rnin) a radio messa)e, or b 'isitin)$ In eiter ase, te response (ill likel be limited b te &inite 'al8e o& te speed o& li)t$ *it tese (ildl 8nertain n8mbers, te ans(er to o8r 8nintentional mid-ent8r all into te depts o& spae (ill not arri'e 8ntil aro8nd te ear "350$ I& teAre &arter a(a, o& o8rse, it (ill take lon)er? and i& m8 &arter a(a, m8 lon)er$ e interestin) possibilit arises tat o8r &irst reeipt o& a messa)e &rom an alien i'iliation, a messa)e intended &or 8s =not H8st an all-points b8lletin<, (ill o8r in a time (en (e are (ell sit8ated on man (orlds in o8r solar sstem and preparin) to mo'e on$
1;;
*it or (ito8t s8 a messa)e, to8), (e (ill a'e reason to ontin8e o8t(ard, seekin) oter solar sstems$ 2rGe'en sa&er in tis 8npreditable and 'iolent setor o& te /alaCGto seK8ester some o& 8s in sel&-s8&&iient abitations in interstellar spae, &ar &rom te dan)ers onstit8ted b te stars$ S8 a &8t8re (o8ld, I tink, nat8rall e'ol'e, b slo( inrements, e'en (ito8t an )rand )oal o& interstellar tra'el: %or sa&et, some omm8nities ma (is to se'er teir ties (it te rest o& 8manitG 8nin&l8ened b oter soieties, oter etial odes, oter tenolo)ial imperati'es$ In a time (en omets and asteroids are bein) ro8tinel repositioned, (e (ill be able to pop8late a small (orld and ten 8t it loose$ In s8essi'e )enerations, as tis (orld sped o8t(ard, te Eart (o8ld &ade &rom bri)t star to pale dot to in'isibilit? te S8n (o8ld appear dimmer, 8ntil it (as no more tan a 'a)8el ello( point o& li)t, lost amon) to8sands o& oters$ e tra'elers (o8ld approa interstellar ni)t$ Some s8 omm8nities ma be ontent (it oasional radio and laser tra&&i (it te old ome (orlds$ 2ters, on&ident o& te s8periorit o& teir o(n s8r'i'al anes and (ar o& ontamination, ma tr to disappear$ eraps all ontat (it tem (ill 8ltimatel be lost, teir 'er eCistene &or)otten$ E'en te reso8res o& a siable asteroid or omet are &inite, to8), and e'ent8all more reso8res m8st be so8)t else(ereGespeiall (ater, needed &or drink, &or a breatable oC)en atmospere, and &or dro)en to po(er &8sion reators$ So in te lon) r8n tese omm8nities m8st mi)rate &rom (orld to (orld, (it no lastin) loalt to an$ *e mi)t all it pioneerin), or omesteadin)$ less smpateti obser'er mi)t desribe it as s8kin) dr te reso8res o& little (orld a&ter little (orld$ B8t tere are a trillion little (orlds in te 2ort +omet +lo8d$ .i'in) in small n8mbers on a modest stepmoter (orld &ar &rom te S8n, (e (ill kno( tat e'er srap o& &ood and e'er drop o& (ater is dependent on te smoot operation o& a &arsi)ted tenolo)? b8t tese onditions are not radiall 8nlike tose to (i (e are alread a8stomed$ !i))in) reso8res o8t o& te )ro8nd and stalkin) passin) reso8res seem oddl &amiliar, like a &or)otten memor o& ildood: It is, (it a &e( si)ni&iant an)es, te strate) o& o8r 8nter-)aterer anestors$ %or 99$9 perent o& te ten8re o& 8mans on Eart, (e li'ed s8 a li&e$ >8d)in) &rom some o& te last s8r'i'in) 8nter-)aterers H8st be&ore te (ere en)8l&ed b te present )lobal i'iliation, (e ma a'e been relati'el app$ ItAs te kind o& li&e tat &or)ed 8s$ So a&ter a brie&, onl partiall s8ess&8l sedentar eCperiment, (e ma beome (anderers a)ain-more tenolo)ial tan last time, b8t e'en ten o8r tenolo), stone tools and &ire, (as o8r onl ed)e a)ainst eCtintion$ I& sa&et lies in isolation and remoteness, ten some o& o8r desendants (ill e'ent8all emi)rate to te o8ter omets o& te 2ort +lo8d$ *it a trillion ometar n8lei, ea separated &rom te neCt b abo8t as m8 as ars is &rom Eart, tere (ill be a )reat deal to do o8t tere$ 1 1
E'en i& (e are not in an parti8lar 8rr, (e ma be able b ten to make small (orlds mo'e &aster tan (e an make spaera&t Vo$ager spaera&tGla8ned in te remote t(entiet ent8rG mo'e toda$ I& so, o8r desendants (ill e'ent8all o'ertake te t(o be&ore te lea'e te 2ort +lo8d, be&ore te make &or interstellar spae$ eraps te (ill retrie'e tese derelit sips o& lon) a)o$ 2r peraps te (ill permit tem to sail on$
1;9
e o8ter ed)e o& te S8nAs 2ort +lo8d is peraps al&(a to te nearest star$ Not e'er oter star as an 2ort +lo8d, b8t man probabl do$ s te S8n passes nearb stars, o8r 2ort +lo8d (ill eno8nter, and partiall pass tro8), oter omet lo8ds, like t(o s(arms o& )nats interpenetratin) b8t not ollidin)$ o o8p a omet o& anoter star (ill ten be not m8 more di&&i8lt tan to o8p one o& o8r o(n$ %rom te &rontiers o& some oter solar sstem te ildren o& te bl8e dot ma peer lon)in)l at te mo'in) points o& li)t denotin) s8bstantial =and (ell-lit< planets$ Some omm8nitiesG&eelin) te anient 8man lo'e &or oeans and s8nli)t stirrin) (itin temGma be)in te lon) Ho8rne do(n to te bri)t, (arm, and lement planets o& a ne( s8n$ 2ter omm8nities ma onsider tis last strate) a (eakness$ lanets are assoiated (it nat8ral atastropes$ lanets ma a'e pre-eCistin) li&e and intelli)ene$ lanets are eas &or oter bein)s to &ind$ Better to remain in te darkness$ Better to spread o8rsel'es amon) man small and obs8re (orlds$ Better to sta idden$
ONCE WE CAN SENDo8r
maines and o8rsel'es &ar &rom ome, &ar &rom te planetsGone (e
reall enter te teater o& te ni'erseG(e are bo8nd to ome 8pon penomena 8nlike antin) (eA'e e'er eno8ntered$ ere are tree possible eCamples: %irst: Startin) some 550 astronomial 8nits =< o8tGabo8t ten times &arter &rom te S8n tan >8piter, and tere&ore m8 more aessible tan te 2ort +lo8dGtereAs sometin) eCtraordinar$ >8st as an ordinar lens &o8ses &ar-o&& ima)es, so does )ra'it$ =/ra'itational lensin) b distant stars and )alaCies is no( bein) deteted$< %i'e 8ndred &i&t &rom te S8n Gonl a ear a(a i& (e o8ld tra'el at 1 perent te speed o& li)tGis (ere te &o8s be)ins =alto8) (en e&&ets o& te solar orona, te alo o& ionied )as s8rro8ndin) te S8n, are taken into ao8nt, te &o8s ma be onsiderabl &arter o8t<$ ere, distant radio si)nals are enormo8sl enaned, ampli&in) (ispers$ e ma)ni&iation o& distant ima)es (o8ld allo( 8s =(it a modest radio telesope< to resol'e a ontinent at te distane o& te nearest star and te inner Solar Sstem at te distane o& te nearest spiral )alaC$ I& o8 are &ree to roam an ima)inar sperial sell at te appropriate &oal distane and entered on te S8n, o8 are &ree to eCplore te ni'erse in st8pendo8s ma)ni&iation, to peer at it (it 8npreedented larit, to ea'esdrop on te radio si)nals o& distant i'iliations, i& an, and to )limpse te earliest e'ents in te istor o& te ni'erse$ lternati'el, te lens o8ld be 8sed te oter (a, to ampli& a 'er modest si)nal o& o8rs so it o8ld be eard o'er immense distanes$ ere are reasons tat dra( 8s to 8ndreds and to8sands o& $ 2ter i'iliations (ill a'e teir o(n re)io ns o& )ra'itational &o8sin), dependin) on te mass and radi8s o& teir star, some a little loser, some a little &arter a(a tan o8rs$ /ra'itational lensin) ma ser'e as a ommon ind8ement &or i'iliations to eCplore te re)ions H8st beond te planetar parts o& teir solar sstems$ Seond: Spend a moment tinkin) abo8t bro(n d(ar&s, potetial 'er lo( temperat8re stars, onsiderabl more massi'e tan >8piter, b8t onsiderabl less massi'e tan te S8n$ Nobod kno(s i& bro(n d(ar&s eCist$ Some eCperts, 8sin) nearer stars as )ra'itational lenses to detet te presene o& more distant ones, laim to a'e &o8nd e'idene o& bro(n d(ar&s$ %rom 190
te tin &ration o& te (ole sk tat as so &ar been obser'ed b tis teniK8e, an enormo8s n8mber o& bro(n d(ar&s is in&erred$ 2ters disa)ree$ In te 1950s, it (as s8))ested b te astronomer arlo( Saple o& ar'ard tat bro(n d(ar&sGe alled tem .illip8tian starsG (ere inabited$ e pit8red teir s8r&aes as (arm as a >8ne da in +ambrid)e, (it lots o& area$ e (o8ld be stars tat 8mans o8ld s8r'i'e on and eCplore$ ird: e psiists B$ >$ +arr and Stepen a(kin) o& +ambrid)e ni'ersit a'e so(n tat &l8t8ations in te densit o& matter in te earliest sta)es o& te ni'erse o8ld a'e )enerated a (ide 'ariet o& small blak oles$ rimordial blak olesGi& te eCistGm8st dea b emittin) radiation to spae, a onseK8ene o& te la(s o& K8ant8m meanis$ e less massi'e te blak ole, te &aster it dissipates$ n primordial blak ole in te &inal sta)es o& dea toda (o8ld a'e to (ei) abo8t as m8 as a mo8ntain$ ll te smaller ones are )one$ Sine te ab8ndaneGto sa notin) o& te eCisteneGo& primordial blak oles depends on (at appened in te earliest moments a&ter te Bi) Ban), no one an be s8re tat tere are an to be &o8nd? (e ertainl anAt be s8re tat an lie nearb$ Not 'er restriti'e 8pper limits on teir ab8ndane a'e been set b te &ail8re so &ar to &ind sort )amma ra p8lses, a omponent o& te a(kin) radiation$ In a separate st8d, /$ E$ Bro(n o& +alte and te pioneerin) n8lear psiist ans Bete o& +ornell s8))est tat abo8t a billion non-primordial blak oles are stre(n tro8) te /alaC, )enerated in te e'ol8tion o& stars$ I& so, te nearest ma be onl 10 or "0 li)tears a(a$ I& tere are blak oles (itin reaG(eter teAre as massi'e as mo8ntains or as starsG (e (ill a'e amain) psis to st8d &irstand, as (ell as a &ormidable ne( so8re o& ener)$ B no means do I laim tat bro(n d(ar&s or primordial blak oles are likel (itin a &e( li)t-ears, or an(ere$ B8t as (e enter interstellar spae, it is ine'itable tat (e (ill st8mble 8pon (ole ne( ate)ories o& (onders and deli)ts, some (it trans&ormin) pratial appliations$ I do not kno( (ere m train o& ar)8ment ends$ s more time passes, attrati'e ne( deniens o& te osmi oo (ill dra( 8s &arter o8t(ard, and inreasin)l improbable and deadl atastropes m8st ome to pass$ e probabilities are 8m8lati'e$ B8t, as time )oes on, tenolo)ial speies (ill also ar8e )reater and )reater po(ers, &ar s8rpassin) an (e an ima)ine toda$ eraps, i& (e are 'er skill&8l =l8k, I tink, (onAt be eno8)<, (e (ill 8ltimatel spread &ar &rom ome, sailin) tro8) te starr aripela)os o& te 'ast ilk *a /alaC$ I& (e ome 8pon anone elseGor, more likel, i& te ome 8pon 8sG(e (ill armonio8sl interat$ Sine oter spae&arin) i'iliations are likel to be m8 more ad'aned tan (e, K8arrelsome 8mans in interstellar spae are 8nlikel to last lon)$ E'ent8all, o8r &8t8re ma be as #oltaire, o& all people, ima)ined: Sometimes b te elp o& a s8nbeam, and sometimes b te on'eniene o& a omet, QteR )lided &rom spere to spere, as a bird ops &rom bo8) to bo8)$ In a 'er little time QteR posted tro8) te ilk *a $ $ $
191
*e are, e'en no(, diso'erin) 'ast n8mbers o& )as and d8st disks aro8nd o8n) starsGte 'er str8t8res o8t o& (i, in o8r solar sstem &o8r and a al& billion ears a)o, te Eart and te oter planets &ormed$ *eAre be)innin) to 8nderstand o( &ine d8st )rains slo(l )ro( into (orlds? o( bi) Eartlike planets arete and ten K8ikl apt8re dro)en and eli8m to beome te idden ores o& )as )iants? and o( small terrestrial planets remain omparati'el bare o& atmospere$ *e are reonstr8tin) te istories o& (orldsGo( mainl ies and or)anis olleted to)eter in te ill o8tskirts o& te earl Solar Sstem, and mainl rok and metal in te inner re)ions (armed b te o8n) S8n$ *e a'e be)8n to reo)nie te dominant role o& earl ollisions in knokin) (orlds o'er, )o8)in) 8)e raters and basins in teir s8r&aes and interiors, spinnin) tem 8p, makin) and obliteratin) moons, reatin) rin)s, arrin), it ma be, (ole oeans do(n &rom te skies, and ten depositin) a 'eneer o& or)ani matter as te neat &inisin) to8 in te reation o& (orlds$ *e are be)innin) to appl tis kno(led)e to oter sstems$ In te neCt &e( deades (e a'e a real ane o& eCaminin) te lao8t and sometin) o& te omposition o& man oter mat8re planetar sstems aro8nd nearb stars$ *e (ill be)in to kno( (i aspets o& o8r sstem are te r8le and (i te eCeption$ *at is more ommonG planets like >8piter, planets like Nept8ne, or planets like EartD 2r do all oter sstems a'e >8piters and Nept8nes and EartsD *at oter ate)ories o& (orlds are tere, 8rrentl 8nkno(n to 8sD re all solar sstems embedded in a 'ast sperial lo8d o& ometsD ost stars in te sk are not solitar s8ns like o8r o(n, b8t do8ble or m8ltiple sstems in (i te stars are in m8t8al orbit$ re tere planets in s8 sstemsD I& so, (at are te likeD I&, as (e no( tink, planetar sstems are a ro8tine onseK8ene o& te ori)in o& s8ns, a'e te &ollo(ed 'er di&&erent e'ol8tionar pats else(ereD *at do elderl planetar sstems, billions o& ears more e'ol'ed tan o8rs, look likeD In te neCt &e( ent8ries o8r kno(led)e o& oter sstems (ill beome inreasin)l ompreensi'e$ *e (ill be)in to kno( (i to 'isit, (i to seed, and (i to settle$ Ima)ine (e o8ld aelerate ontin8o8sl at 1 )G(at (eAre om&ortable (it on )ood old
"erra irmaGto te midpoint o& o8r 'oa)e, and deelerate ontin8o8sl at 1 ) 8ntil (e arri'e at o8r destination$ It (o8ld ten take a da to )et to ars, a (eek and a al& to l8to, a ear to te 2ort +lo8d, and a &e( ears to te nearest stars$ E'en a modest eCtrapolation o& o8r reent ad'anes in transportation s8))ests tat in onl a &e( ent8ries (e (ill be able to tra'el lose to te speed o& li)t$ eraps tis is opelessl optimisti$ eraps it (ill reall take millennia or more$ B8t 8nless (e destro o8rsel'es &irst (e (ill be in'entin ) ne( tenolo)ies as stran)e to 8s as Vo$ager mi)t be to o8r 8nter)aterer anestors$ E'en toda (e an tink o& (asGl8ms, r8ino8sl eCpensi'e, ine&&iient to be s8reGo& onstr8tin) a starsip tat approaes li)t speed$ In time, te desi)ns (ill beome more ele)ant, more a&&ordable, more e&&iient$ e da (ill ome (en (e o'erome te neessit o& H8mpin) &rom omet to omet$ *e (ill be)in to soar tro8) te li)t-ears and, as St$ 8)8stine said o& te )ods o& te anient /reeks and omans, olonie te sk$ S8 desendants ma be tens or 8ndreds o& )enerations remo'ed &rom anone (o e'er li'ed on te s8r&ae o& a planet$ eir 8lt8res (ill be di&&erent, teir tenolo)ies &ar ad'aned, 19"
teir lan)8a)es an)ed, teir assoiation (it maine intelli)ene m8 more intimate, peraps teir 'er appearane markedl altered &rom tat o& teir nearl mtial anestors (o &irst tentati'el set &ort in te late t(entiet ent8r into te sea o& spae$ B8t te (ill be 8man, at least in lar)e part? te (ill be pratitioners o& i) tenolo)? te (ill a'e istorial reords$ !espite 8)8stineAs H8d)ment on .otAs (i&e, tat no one (o is bein) sa'ed so8ld lon) &or (at e is lea'in), te (ill not (oll &or)et te Eart$ B8t (eAre not nearl read, o8 ma be tinkin)$ s #oltaire p8t it in is Memnon o8r little terraK8eo8s )lobe is te mado8se o& tose 8ndred to8sand millions 1 o& (orlds$ *e, (o annot e'en p8t o8r o(n planetar ome in order, ri'en (it ri'alries and atreds, despoilin) o8r en'ironment, m8rderin) one anoter tro8) irritation and inattention as (ell as on deadl p8rpose, and moreo'er a speies tat 8ntil onl reentl (as on'ined tat te ni'erse (as made &or its sole bene&itGare (e to 'ent8re o8t into spae, mo'e (orlds, reen)ineer planets, spread to nei)borin) star sstemsD I do not ima)ine tat it is preisel o'ian planets and te 8iper +omet Belt (ill take man )enerations more$ e 2ort +lo8d (ill reK8ire m8 lon)er still$ B te time (eAre read to settle e'en te nearest oter planetar sstems, (e (ill a'e an)ed$ e simple passa)e o& so man )enerations (ill a'e an)ed 8s$ e di&&erent ir8mstanes (e (ill be li'in) 8nder (ill a'e an)ed 8s$ rosteses and )eneti en)ineerin) (ill a'e an)ed 8s$ Neessit (ill a'e an)ed 8s$ *eAre an adaptable speies$ It (ill not be (e (o rea lpa +enta8ri and te oter nearb stars$ It (ill be a speies 'er like 8s, b8t (it more o& o8r stren)ts and &e(er o& o8r (eaknesses, a speies ret8rned to ir8mstanes more like tose &or (i it (as ori)inall e'ol'ed, more on&ident, &arseein), apable, and pr8dentGte sorts o& bein)s (e (o8ld (ant to represent 8s in a ni'erse tat, &or all (e kno(, is &illed (it speies m8 older, m8 more po(er&8l, and 'er di&&erent$ e 'ast distanes tat separate te stars are pro'idential$ Bein)s and (orlds are K8arantined &rom one anoter$ e K8arantine is li&ted onl &or tose (it s8&&iient sel&kno(led)e and H8d)ment to a'e sa&el tra'eled &rom star to star$
ON IMMENSE TIMESCALES,in
8ndreds o& millions to billions o& ears, te enters o& )alaCies
eCplode$ *e see, sattered aross deep spae, )alaCies (it ati'e n8lei, K8asars, )alaCies distorted b ollisions, teir spiral arms disr8pted, star sstems blasted (it radiation or )obbled 1
'al8e tat niel approCimates modern estimates o& te n8mber o& planets orbitin) stars in te ilk *a /alaC$
193
8p b blak olesGand (e )ater tat on s8 timesales e'en interstellar spae, e'en )alaCies ma not be sa&e$ ere is a alo o& dark matter s8rro8ndin) te ilk *a, eCtendin) peraps al&(a to te distane o& te neCt spiral )alaC =31 in te onstellation ndromeda, (i also ontains 8ndreds o& billions o& stars<$ *e do not kno( (at tis dark matter is, or o( it is arran)edG b8t some1 o& it ma be in (orlds 8ntetered to indi'id8al stars$ I& so, o8r desendants o& te remote &8t8re (ill a'e an opport8nit, o'er 8nima)inable inter'als o& time, to beome establised in inter)alati spae, and to tiptoe to oter )alaCies$ B8t on te timesale &or pop8latin) o8r )alaC, i& not lon) be&ore, (e m8st ask: o( imm8table is tis lon)in) &or sa&et tat dri'es 8s o8t(ardD *ill (e one da &eel ontent (it te time o8r speies as ad and o8r s8esses, and (illin)l eCit te osmi sta)eD illions o& ears &rom no(Gprobabl m8 soonerG(e (ill a'e made o8rsel'es into sometin) else$ E'en i& (e do notin) intentionall, te nat8ral proess o& m8tation and seletion (ill a'e (orked o8r eCtintion or e'ol'ed 8s into some oter speies on H8st s8 a timesale =i& (e ma H8d)e b oter mammals<$ 2'er te tpial li&etime o& a mammalian speies, e'en i& (e (ere able to tra'el lose to te speed o& li)t and (ere dediated to notin) else, (e o8ld not, I tink, eCplore e'en a representati'e &ration o& te ilk *a /alaC$ ereAs H8st too m8 o& it$ nd beond are a 8ndred billion )alaCie s more$ *ill o8r present moti'ati ons remain 8nan)ed o'er )eolo)ial, m8 less osmolo)ial, timesalesG(en (e o8rsel'es a'e been trans&i)8redD In s8 remote epos, (e ma diso'er o8tlets &or o8r ambitions &ar )rander and more (ort tan merel pop8latin) an 8nlimited n8mber o& (orlds$ eraps, some sientists a'e ima)ined, (e (ill one da reate ne( &orms o& li&e, link minds, olonie stars, reon&i)8re )alaCies, or pre'ent, in a nearb 'ol8me o& spae, te eCpansion o& te ni'erse$ In a 1993 artile in te Ho8rnal u7lear P$i7 te psiist ndrei .indeGonei'abl, in a pla&8l moodGs8))ests tat laborator eCperiments =it (o8ld a'e to be K8ite a laborator< to reate separate, losed-o&&, eCpandin) 8ni'erses mi)t 8ltimatel be possible$ o(e'er, e (rites to me, I msel& do not kno( (eter Qtis s8))estionR is simpl a Hoke or sometin) else$ In s8 a list o& proHets &or te &ar &8t8re, (e (ill a'e no di&&i8lt in reo)niin) a ontin8in) 8man ambition to arro)ate po(ers one onsidered )odlikeGor, in tat oter more eno8ra)in) metapor, to omplete te +reation$ FOR MANY PAGES NOW, (e
a'e le&t te realm o& pla8sible onHet8re &or te ead intoCiation
o& nearl 8nonstrained spe8lation$ It is time to ret8rn to o8r o(n a)e$ )rand&ater, born be&ore radio (a'es (ere e'en a laborator 8riosit, almost li'ed to see te &irst arti&iial satellite beepin) do(n at 8s &rom spae$ ere are people (o (ere born be&ore tere (as s8 a tin) as an airplane, and (o in old a)e sa( &o8r sips la8ned to te stars$ %or all o8r &ailin)s, despite o8r limitations and &allibilities, (e 8mans are apable o& )reatness$ is is tr8e o& o8r siene and some areas o& o8r tenolo), o& o8r art, m8si, 1
ost o& it ma be in nonbaroni matter, not made o& o8r &amiliar protons and ne8trons, and not anti-matter eiter$ 2'er 90 perent o& te mass o& te ni'erse seems to be in tis dark, K8intessential, deepl msterio8s st8&& (oll 8nkno(n on Eart$ eraps (e (ill one da not onl 8nderstand it, b8t also &ind a 8se &or it$
194
literat8re, altr8ism, and ompassion, and e'en, on rare oasion, o& o8r statera&t$ *at ne( (onders 8ndreamt o& in o8r time (ill (e a'e (ro8)t in anoter )enerationD nd anoterD o( &ar (ill o8r nomadi speies a'e (andered b te end o& te neCt ent8rD nd te neCt millenni8mD (o billion ears a)o o8r anestors (ere mirobes? a al&billion ears a)o, &is? a 8ndred million ears a)o, sometin) like mie? ten million ears a)o, arboreal apes? and a million ears a)o, proto-8mans p8lin) o8t te tamin) o& &ire$ 28r e'ol8tionar linea)e is marked b master o& an)e$ In o8r time, te pae is K8ikenin)$ *en (e &irst 'ent8re to a near-Eart asteroid, (e (ill a'e entered a abitat tat ma en)a)e o8r speies &ore'er$ e &irst 'oa)e o& men and (omen to ars is te ke step in trans&ormin) 8s into a m8ltiplanet speies$ ese e'ents are as momento8s as te oloniation o& te land b o8r ampibian anestors and te desent &rom te trees b o8r primate anestors$ %is (it r8dimentar l8n)s and &ins sli)tl adapted &or (alkin) m8st a'e died in )reat n8mbers be&ore establisin) a permanent &ootold on te land$ s te &orests slo(l reeded, o8r 8pri)t apelike &orebears o&ten s8rried bak into te trees, &leein) te predators tat stalked te sa'annas$ e transitions (ere pain&8l, took millions o& ears, and (ere impereptible to tose in'ol'ed$ In o8r ase te transition o8pies onl a &e( )enerations, and (it onl a and&8l o& li'es lost$ e pae is so s(i&t tat (e are still barel able to )rasp (at is appenin)$ 2ne te &irst ildren are born o&& Eart? one (e a'e bases and omesteads on asteroids, omets, moons, and planets? one (eAre li'in) o&& te land and brin)in) 8p ne( )enerations on oter (orlds, sometin) (ill a'e an)ed &ore'er in 8man istor$ B8t inabitin) oter (orlds does not impl abandonin) tis one, an more tan te e'ol8tion o& ampibians meant te end o& &is$ %or a 'er lon) time onl a small &ration o& 8s (ill be o8t tere$ In modern *estern soiet, (rites te solar +arles .indolm, te erosion o& tradition and te ollapse o& aepted reli)io8s belie& lea'es 8s (ito8t a
"elo Qan end to (i (e stri'eR, a santi&ied notion o& 8manitAs potential$ Bere&t o& a sared proHet, (e a'e onl a demsti&ied ima)e o& a &rail and &allible 8manit no lon)er apable o& beomin) )od-like$ I belie'e it is ealtGindeed, essentialGto keep o8r &railt and &allibilit &irml in mind$ I (orr abo8t people (o aspire to be )od-like$ B8t as &or a lon)-term )oal and a sared proHet, tere is one be&ore 8s$ 2n it te 'er s8r'i'al o& o8r speies depends$ I& (e a'e been loked and bolted into a prison o& te sel&, ere is an esape atGsometin) (ort, sometin) 'astl lar)er tan o8rsel'es, a r8ial at on beal& o& 8manit$ eoplin) oter (orlds 8ni&ies nations and etni )ro8ps, binds te )enerations, and reK8ires 8s to be bot smart and (ise$ It liberates o8r nat8re and, in part, ret8rns 8s to o8r be)innin)s$ E'en no(, tis ne( "elo i (itin o8r )rasp$ e pioneerin) psolo)ist *illiam >ames alled reli)ion a &eelin) o& bein) at ome in te ni'erse$ 28r tenden as been, as I desribed in te earl apters o& tis book, to pretend tat te ni'erse is o( (e (is o8r ome (o8ld be, rater tan to re'ise o8r notion o& 195
(atAs ome so it embraes te ni'erse$ I&, in onsiderin) >amesA de&inition, (e mean te real ni'erse, ten (e a'e no tr8e reli)ion et$ at is &or anoter time, (en te stin) o& te /reat !emotions is (ell beind 8s, (en (e are alimatied to oter (orlds and te to 8s, (en (e are spreadin) o8t(ard to te stars$ e +osmos eCtends, &or all pratial p8rposes, &ore'er$ &ter a brie& sedentar iat8s, (e are res8min) o8r anient nomadi (a o& li&e$ 28r remote desendants, sa&el arraed on man (orlds tro8) te Solar Sstem and beond, (ill be 8ni&ied b teir ommon erita)e, b teir re)ard &or teir ome planet, and b te kno(led)e tat, (ate'er oter li&e ma be, te onl 8mans in all te ni'erse ome &rom Eart$ e (ill )ae 8p and strain to &ind te bl8e dot in teir skies$ e (ill lo'e it no less &or its obs8rit and &ra)ilit$ e (ill mar'el at o( '8lnerable te repositor o& all o8r potential one (as, o( perilo8s o8r in&an, o( 8mble o8r be)innin)s, o( man ri'ers (e ad to ross be&ore (e &o8nd o8r (a$
196
B2 E 2 +. S/N (as te !a'id !8nan ro&essor o& stronom and Spae Sienes and !iretor o& te .aborator &or lanetar St8dies at +ornell ni'ersit$ e plaed a leadin) role in te merian spae pro)ram sine its ineption$ e (as a ons8ltant and ad'isor to NS sine te 1950s, brie&ed te pollo astrona8ts be&ore teir &li)ts to te oon, and (as an eCperimenter on te Mariner Viking Vo$ager and %alileo eCpeditions to te planets$ e elped sol'e te msteries o& te i) temperat8re o& #en8s =ans(er: massi'e )reeno8se e&&et<, te seasonal an)es on ars =ans(er: (indblo(n d8st<, and te reddis ae o& itan =ans(er: ompleC or)ani mole8les<$ %or is (ork, !r$ Sa)an reei'ed te NS medals &or ECeptional Sienti&i ie'ement and =t(ie< &or !istin)8ised 8bli Ser'ie, as (ell as te NS pollo ie'ement (ard$ steroid "709 Sa)an is named a&ter im$ e (as also a(arded te >on %$ enned strona8tis (ard o& te merian strona8tial Soiet, te ECplorers +l8b 75t nni'ersar (ard, te onstantin siolko'sk edal o& te So'iet +osmona8ts %ederation, and te as8rsk (ard o& te merian stronomial Soiet =&or is eCtraordinar ontrib8tions to te de'elopment o& planetar siene $$$$ s a sientist trained in bot astronom and biolo), !r$ Sa)an as made seminal ontrib8tions to te st8d o& planetar atmosperes, planetar s8r&aes, te istor o& te Eart, and eCobiolo)$ an o& te most prod8ti'e planetar sientists (orkin) toda are is present and &ormer st8dents and assoiates<$
+N2*.E!/ENS ost o& te material in tis book is ne($ n8mber o& apters a'e e'ol'ed &rom artiles &irst p8blised in Parae ma)aine, a s8pplement to te S8nda editions o& merian ne(spapers (i, (it an estimated ;0 million readers, ma be te most (idel read ma)aine in te (orld$ I am )reatl indebted to *alter nderson, te editor-in-ie&, and !a'id +8rrier, te eCe8ti'e editor, &or teir eno8ra)ement and editorial (isdom? and to te readers o& Parae (ose letters a'e elped me 8nderstand (ere I a'e been lear, and (ere obs8re, and o( m ar)8ments are reei'ed$ ortions o& oter apters a'e emer)ed &rom artiles p8blised in !ue in S7ien7e an /e7nolog$ .i7o4er /e Plane"ar$ epor" S7ien"ii7 Ameri7an and Popular Me7ani73 spets o& tis book a'e been dis8ssed (it a lar)e n8mber o& &riends and ollea)8es, (ose omments a'e )reatl impro'e d it$ lto8) tere are too man to list b name, I (o8ld like to eCpress m real )ratit8de to all o& tem$ I (ant espeiall, to8), to tank Norman 8)8stine, o)er Bonnet, %reeman !son, .o8is %riedman, E'erett /ibson, !aniel /oldin, >$ iard /ott III, ndrei .inde, >on .omber), !a'id orrison, oald Sa)dee', Ste'en Soter, ip rone, and %rederik 8rner &or teir omments on all or part o& te man8sript? Set a8&mann, eter omas, and >os8a /rinspoon &or teir elp (it tables and )raps? and a brilliant arra o& astronomial artists, akno(led)ed at ea ill8stration, (o a'e permitted me to so(ase some o& teir (ork$ ro8) te )enerosit o& at ot, l E(en, and .arr Soderblom, IA'e been able to displa some o& te eCeptional potomosias, airbr8s maps, and oter red8tions o& NS ima)es aomplised at te Bran o& stro)eolo), $S$ /eolo)ial S8r'e$ I am indebted to ndrea Barnett, .a8rel arker, >enni&er Bland, .oren oone, arenn /obret, !ebora earlstein, and te late Eleanor ork &or teir able tenial assistane? and to arr E'ans, *alter
197
*eint, nn /odo&&, at osenbloom, nd +arpenter, arta S(art, and lan aobert on te prod8tion end$ Bet ondrea8 is responsible &or m8 o& te desi)n ele)ane on tese pa)es$ 2n matters o& spae poli, I a'e bene&ited &rom dis8ssions (it oter members o& te board o& diretors o& e lanetar Soiet, espeiall Br8e 8rra, .o8is %riedman, Norman 8)8stine, >oe an, and te late omas 2$ aine$ !e'oted to te eCploration o& te Solar Sstem, te sear &or eCtraterrestrial li&e, and international missions b 8mans to oter (orlds, it is te or)aniation tat most nearl embodies te perspeti'e o& te present book$ ose readers interested in more in&ormation on tis nonpro&it or)aniation, te lar)est spae-interest )ro8p on Eart, ma ontat: E .NE S2+IE 65 N$ +atalina 'en8e asadena, + 91106 el$: 1-;00-9 *2.!S s is tr8e o& e'er book IA'e (ritten sine 1977, I am more )rate&8l tan I an sa to nn !r8an &or searin) ritiism and &8ndamental ontrib8tions bot on ontent and stle$ In te 'astness o& spae and te immensit o& time, it is still m Ho to sare a planet and an epo (it nnie$
19;
E%EEN+ES (a e< 7i"a"ion an ugge"ion or ur"er reaing)
PLANETARY EXPLORATION IN GENERAL:
>$ ell Beatt and ndre( +aiken, editors, /e e< Solar S$"em tird edition =+ambrid)e: +ambrid)e ni'ersit ress, 1990<$ Eri +aisson and Ste'e illan, A"ronom$ /oa$ =En)le(ood +li&&s, N>: rentie all, 1993<$ Ester +$ /oddard, editor, /e Paper o o;er" 3 %oar =Ne( ork: /ra(-ill, 1970< =tree 'ol8mes<$ onald /reele, Plane"ar$ &an7ape seond edition =Ne( ork: +apman and all, 1994<$ *illiam >$ a8&mann III, ni4ere &o8rt edition =Ne( ork: *$ $ %reeman, 1993 <$ arr $ S(een, >r$, S"aru" "o Plane" =Ne( ork: St$ a rtinAs, 1994<$ on iller and *illiam $ artmann, /e %ran /our= A /ra4eler %uie "o "e Solar S$"em re'ised edition =Ne( ork: *orkman, 1993<$ !a'id orrison, Exploring Plane"ar$ :orl =Ne( ork: Sienti&i merian Books, 1993<$ Br8e +$ 8rra, ourne$ "o "e Plane" =Ne( ork: *$*$ Norton, 19;9<$ >a $ asao&&, A"ronom$= rom Ear" "o "e ni4ere =Ne( ork: Sa8nders, 1993<$ +arl Sa)an, #omo =Ne( ork: andom o8se, 19;0<$ onstantin siolko'sk, /e #all o "e #omo =oso(: %orei)n .an)8a)es 8blisin) o8se, 1960< =En)lis translation<$ CHAPTER +, THE GREAT DEMOTIONS
>on !$ Barron and %rank >$ ipler,/e An"ropi7 #omologi7al Prin7iple =Ne( ork: 2C&ord ni'ersit ress, 19;6<$ $ .inde, Par"i7le P$i7 an !nla"ionar$ #omolog$=ar(ood adem 8blisers, 1991<$ B$ Ste(art, Siene or nimismD, #rea"ion CE4olu"ion 'ol$ 1", no$ 1 =199"<, pp$ 1;-19$ Ste'en *einber), .ream o a inal /eor$ =Ne( ork: #inta)e Books, 1994<$ CHAPTER , A UNIVERSE NOT MADE FOR US
Brian ppleard, ner"aning "e Preen"= S7ien7e an "e Soul o Moern Man=.ondon: iadoran Books .td$, 199"<$ assa)es K8oted appear, in order, on te &ollo(in) pa)es: "3", "7, 3", 19, 19, "7, 9, Ci', 137, 11"-113, "06, 10, "39, ;, ;$ >$ B$ B8r, i"or$ o "e Papa7$ in "e 19" #en"ur$ =Ne( ork: Soken, 1964<$ ere, as in man oter so8res, te 1;64 S$lla;u is transribed into its positi'e &orm =e$)$, !i'ine re'elation is per&et< rater tan as part o& a list o& ondemned errors =!i'ine re'elation is imper&et<$ CHAPTER $, IS THERE INTELLIGENT LIFE ON EARTH(
+arl Sa)an, *$ $ ompson, obert +arlsson, !onald /8rnett, and +arles ord, Sear &or .i&e on Eart &rom te %alileo Spaera&t, a"ure 4ol3 365 =1993<, pp$ 715-7"1$ CHAPTER , AMONG THE MOONS OF SATURN
199
>onatan .8nine, !oes itan a'e 2eansD, Ameri7an S7ien"i" 4ol3 ;" =1994<, pp$ 134-144$ +arl Sa)an, *$ eid ompson, and Bis8n N$ are, itan: .aborator &or rebiolo)ial 2r)ani +emistr, A77oun" o #emi7al eear7 'ol$ "5 =199"<, pp$ ";6-"9"$
>$ *illiam Sop&,
Maor E4en" in "e i"or$ o &ie =Boston: >ones and Bartlett, 199"<$
CHAPTER #, THE FIRST NEW PLANET Bernard +oen, /$ !$ +assini and te N8mber o& te lanets, in a"ure Experimen" an "e S7ien7e re'or .e'ere and *$ $ Sea, editors =!ordret: l8(er, 1990<$
CHAPTER *, AN AMERICAN SHIP AT THE FRONTIERS O F THE SOLAR SYSTEM
Murmur o Ear" +!-2 o& te Vo$ager interstellar reord, (it introd8tion b +arl Sa)an and nn !r8an =.os n)eles: *arner Ne( edia, 199"<, *N 140""$ leCander *olsan, +on&irmation o& Eart-ass lanets 2rbitin) te illiseond 8lsar S B1"571", Siene, 'ol$ "64 =1994<, pp$ 53;-54"$ CHAPTER !, THE GROUND MELTS
eter +attermole, Venu= /e %eologi7al Sur4e$=Baltimore: >ons opkins ni'ersit ress, 1994<$ eter %ranis, Vol7anoe= A Plane"ar$ Perpe7"i4e=2C&ord: 2C&ord ni'ersit ress, 1993<$
CHAPTER +, THE GIFT OF APOLLO ndre( +aikin, A Man on "e Moon =Ne( ork: #ikin), 1994<$ iael +ollins, &i"o =Ne( ork: /ro'e ress, 19;;<$ !aniel !e8dne, %or)in) issiles into Spaesips, *orld Poli7$ Gournal 4ol3 ", no$ " =Sprin) 19;5<, pp$ "71-303$ arr 8rt, or All Mankin =Ne( ork: tlanti ontl ress, 19;;<$ iard S$ .e(is, /e Vo$age o Apollo= /e Explora"ion o te Moon =Ne( ork: T8adran)le, 1974<$ *alter $ !o8)all, /e ea4en an "e Ear"= A Poli"i7al i"or$ o "e Spa7e Age =Ne( ork: Basi Books, 19;5<$ lan Seperd, !eke Slaton et al$, Moono" =tlanta: perion, 1994<$ !on E$ *ilelms, oa o7k$ Moon= A %eologi" i"or$ or &unar Explora"ion =8son: ni'ersit o& riona ress, 1993<$ CHAPTER , EXPLORING OTHER WORLDS AND PROTECTING THIS ONE
e'in *$ elle, editor,/e ome Plane" =eadin), : ddison*esle, 19;;<$ +arl Sa)an and iard 8ro, A Pa" :ere o Man /oug"= u7lear :in"er an "e En o "e
Arm a7e =Ne( ork: andom o8se, 1990<$ iard 8ro, Ear" ner Siege= Air Pollu"ion an %lo;al #ange =Ne( ork: 2C&ord ni'ersit ress, in press<$ CHAPTER $, THE GATES OF THE WONDER WORLD OPEN
#itor $ Baker, /e #annel o Mar =8stin: ni'ersit o& eCas ress, 19;"<$ iael $ +arr, /e Sura7e o Mar =Ne( a'en: ale ni'ersit ress, 19;1<$ $ $ ie&&er, B$ $ >akosk, +$ *$ Snder, and $ S$ atte(s, editors, Mar =8son: ni'ersit o& riona ress, 199"<$ >on Noble *il&ord, Mar >e7kon= /e M$"erie "e #allenge "e Expe7"a"ion o Our ex" %rea" A4en"ure in Spa7e =Ne( ork: nop&, 1990<$
CHAPTER #, THE MARSH OF CAMARINA +lark $ +apman and !a'id orrison, Impats on te Eart b steroids and +omets: ssessin) te aard, a"ure 4ol3 367 =1994<, pp$ 3340$
"00
$ *$ arris, /$ +ana'an, +$ Sa)an, and S$ >$ 2stro, e !e&letion !ilemma: se 's$ is8se o& enolo)ies &or 'oidin) Interplanetar +ollision aards, in a+ar .ue "o A"eroi an #ome" $ /erels, editor =8son: ni'ersit o& riona ress, 1994<$ >on S$ .e(is and 8t $ .e(is, Spa7e eour7e= >reaking "e >on o Ear" =Ne( ork: +ol8mbia ni'ersit ress, 19;7<$ +$ Sa)an and S$ >$ 2stro, .on)-an)e +onseK8enes o& Interplanetar +ollision aards, !ue in S7ien7e an /e7nolog$ =S8mmer 1994<, pp$ 67-7"$
CHAPTER *, REMAKING THE PLANETS >$ !$ Bernal, /e :orl "e le an "e .e4il=Bloomin)ton, IN: Indiana ni'ersit ress, 1969? &irst edition, 19"9<$ >ames B$ ollak and +arl Sa)an, lanetar En)ineerin), in >$ .e(is and $ atte(s, editors,ear-Ear" eour7e =8son: ni'ersit o& riona ress, 199"<$ CHAPTER !%, DARKNESS
%rank !rake and !a'a Sobel, ! An$one Ou" /ere =Ne( ork: !elaorte, 199"<$ a8l oro(it and +arl Sa)an, roHet E: %i'e-ear ll-Sk Narro(band adio Sear &or ECtraterrestrial Intelli)ene, A"rop$i7al Gournal 'ol$ 415 =199"<, pp$ "1;-"35$ omas $ !ono8), /e Sear7 or Ex"ra"erre"rial !n"elligen7e =Ne( ork: >on *ile and Sons, 19;7<$ +arl Sa)an, #on"a7"= A o4el =Ne( ork: Simon and S8ster, 19;5< $ CHAPTER !, TO THE SKY.
>$ iard /ott III, Impliations o& te +opernian riniple &or 28r %8t8re rospets, a"ure 4ol3 "63 =1993<, pp$ 315-319$
CHAPTER !!, TIPTOEING THROUGH THE MILKY WAY I$ $ +ra(&ord, Interstellar ra'el: e'ie( &or stronomers,Iuar"erl$ Gournal o "e o$al A"ronomi7al So7ie"$ 4ol3 '1 =1990<, p$ 377$ I$ $ +ra(&ord, Spae, *orld /o'ernment, and Ve End o& istor,AHGournal o "e >ri"i !n"erplane"ar$ So7ie"$ 'ol$ 46 =1993<, pp$ 415-4"0$ %reeman >$ !son, /e :orl "e le an "e .e4il=.ondon: Birkbek +olle)e, 197"<$ Ben $ %inne and Eri $ >ones, editors, !n"er"ellar Migra"ion an "e uman Experien7e =Berkele: ni'ersit o& +ali&ornia ress, 19;5<$ %ranis %8k8ama, /e En o i"or$ an "e &a" Man =Ne( ork: e %ree ress, 199"<$ +arles .indolm, #arima =2C&ord: Blak(ell, 1990< $ e omment on te need &or a "elo i in tis book$ E8)ene %$ allo'e and /re)or .$ atlo&&, /e S"arlig" an;ook =Ne( ork: >on *ile and Sons, 19;9<$ +arl Sa)an and nn !r8an, #ome" =Ne( ork: andom o8se, 19;5<$
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