pale blue dot -carl sagan-第21部分

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Sending　people　to　orbit　the　Earth　or　robots　to　orbit　the　Sun　requires　rockets—big；　reliable；　powerful　rockets。　Those　same　rockets　can　be　used　for　nuclear　war。　The　same　technology　that　transports　a　man　to　the　Moon　can　carry　nuclear　warheads　halfway　around　the　world。　The　same　technology　that　puts　an　astronomer　and　a　telescope　in　Earth　orbit　can　also　put　up　a　laser　〃battle　station。〃　Even　back　then；　there　was　fanciful　talk　in　military　circles；　East　and　West；　about　space　as　the　new　〃high　ground；〃　about　the　nation　that　〃controlled〃　space　〃controlling〃　the　Earth。　Of　course　strategic　rockets　were　already　being　tested　on　Earth。　But　heaving　a　ballistic　missile　with　a　dummy　warhead　into　a　target　zone　in　the　middle　of　the　Pacific　Ocean　doesn't　buy　much　glory。　Sending　people　into　space　captures　the　attention　and　Imagination　of　the　world。

You　wouldn't　spend　the　money　to　launch　astronauts　for　this　reason　alone；　but　of　all　the　ways　of　demonstrating　rocket　potency；　this　one　works　best。　It　was　a　rite　of　national　manhood；　the　shape　of　the　boosters　made　this　point　readily　understood　without　anyone　actually　having　to　explain　it。　The　munication　seemed　to　be　transmitted　from　unconscious　mind　to　unconscious　mind　without　the　higher　mental　faculties　catching　a　whiff　of　what　was　going　on。

My　colleagues　today—struggling　for　every　space　science　dollar—may　have　forgotten　how　easy　it　was　to　get　money　for　〃space〃　in　the　glory　days　of　Apollo　and　just　before。　Of　many　examples；　consider　this　exchange　before　the　Defense　Appropriations　Submittee　of　the　House　of　Representatives　in　1958；　only　a　few　months　after　Sputnik　1。　Air　Force　Assistant　Secretary　Richard　E。　Horner　is　testifying；　his　interlocutor　is　Rep。　Daniel　J。　Flood　（Democrat　of　Pennsylvania）：

　

HORNER：　＇W＇hy　is　it　desirable　from　the　military　point　of　view　to　have　a　man　on　the　moon？　Partly；　from　the　classic　point　of　view；　because　it　is　there。　Partly　because　we　might　be　afraid　that　the　U。S。S。R。　might　get　one　there　first　and　realize　advantages　which　we　had　not　anticipated　existed　there　。　。　。

FLOOD：　＇I＇f　we　gave　you　all　the　money　you　said　was　necessary；　regardless　of　how　much　it　was；　can　you　in　the　Air　Force　hit　the　moon　with　something；　anything；　before　Christmas？

HORNER：　I　feel　sure　we　can。　There　is　always　a　certain　amount　of　risk　in　this　kind　of　undertaking；　but　we　feel　that　we　can　do　that；　yes；　sir。

FLOOD：　Have　you　asked　anybody　in　the　Air　Force　or　the　Department　of　Defense　to　give　you　enough　money；

hardware；　and　people；　starting　at　midnight　tonight；　to　chip　a。　piece　out　of　that　ball　of　green　cheese　for　a　Christmas　present　to　Uncle　Sam？　Have　you　asked　for　that？

HORNER：　We　have　submitted　such　a　program　to　the　Office　of　the　Secretary　of　Defense。　It　is　currently　under　consideration。

FLOOD：　I　am　for　giving　it　to　them　as　of　this　minute；　Mr。　Chairman；　with　our　supplemental；　without　waiting　for　somebody　downtown　to　make　up　his　mind　to　ask　for　it。　If　this　man　means　what　he　says　and　if　he　knows　what　he　is　talking　about—and　I　think　he　does—then　this　mittee　should　not　wait　five　minutes　more　today。　We　should　give　him　all　the　money　and　all　the　hardware　and　all　the　people　he　wants；　regardless　of　what　anybody　else　says　or　wants；　and　tell　him　to　go　up　on　top　of　some　hill　and　do　it　without　any　question。

When　President　Kennedy　formulated　the　Apollo　program；　the　Defense　Department　had　a　slew　of　space　projects　under　development—ways　of　carrying　military　personnel　up　into　space；　means　of　conveying　them　around　the　Earth；　robot　weapons　on　orbiting　platforms　intended　to　shoot　down　satellites　and　ballistic　missiles　of　other　nations。　Apollo　supplanted　these　programs。　They　never　reached　operational　status。　A　case　can　be　made　then　that　Apollo　served　another　purpose—to　move　the　U。S。—Soviet　space　petition　from　a　military　to　a　civilian　arena。　There　are　some　who　believe　that　Kennedy　intended　Apollo　as　a　substitute　for　an　anus　race　in　space。　Maybe。

For　me；　the　most　ironic　token　of　that　moment　in　history　is　the　plaque　signed　by　President　Richard　M。　Nixon　that　Apollo　11　took　to　the　Moon。　It　reads：　〃We　came　in　peace　for　all　mankind。〃　As　the　United　States　was　dropping　7？　megatons　of　conventional　explosives　on　small　nations　in　Southeast　Asia；　we　congratulated　ourselves　on　our　humanity：　We　would　harm　no　one　on　a　lifeless　rock。　That　plaque　is　there　still；　attached　to　the　base　of　the　Apollo　11　Lunar　Module；　on　the　airless　desolation　of　the　Sea　of　Tranquility。　If　no　one　disturbs　it；　it　will　still　be　readable　a　million　years　from　now。

Six　more　missions　followed　Apollo　11；　all　but　one　of　which　successfully　landed　on　the　lunar　surface。　Apollo　17　was　the　first　to　carry　a　scientist。　As　soon　as　he　got　there；　the　program　was　canceled。　The　first　scientist　and　the　last　human　to　land　on　the　Moon　were　the　same　person。　The　program　had　already　served　its　purpose　that　July　night　in　1969。　The　half…dozen　subsequent　missions　were　just　momentum。

Apollo　was　not　mainly　about　science。　It　was　not　even　mainly　about　space。　Apollo　was　about　ideological　confrontation　and　nuclear　war—often　described　by　such　euphemisms　as　world　〃leadership〃　and　national　〃prestige。〃　Nevertheless；　good　space　science　was　done。　We　now　know　much　more　about　the　position；　age；　and　history　of　the　Moon　and　the　origin　of　the　lunar　landforms。　We　have　made　progress　in　understanding　where　the　Moon　came　from。　Some　of　us　have　used　lunar　cratering　statistics　to　better　understand　the　Earth　at　the　time　of　the　origin　of　life。　But　more　important　than　any　of　this；　Apollo　provided　an　aegis；　an　umbrella　under　which　brilliantly　engineered　robot　spacecraft　were　dispatched　throughout　the　Solar　System；　making　that　preliminary　reconnaissance　of　dozens　of　worlds。　The　offspring　of　Apollo　have　now　reached　the　planetary　frontiers。

If　not　for　Apollo—and；　therefore；　if　not　for　the　political　purpose　it　served—I　doubt　whether　the　historic　American　expeditions　of　exploration　and　discovery　throughout　the　Solar　System　would　have　occurred；　The　Mariners；　Vikings；　Pioneers；　Voyagers　；and　Galileo　are　among　the　gifts　of　Apollo。　Magellan　and　Cassini　are　more　distant　descendants。　Something　similar　is　true　for　the　pioneering　Soviet　efforts　in　Solar　System　exploration；　including　the　first　soft　landings　of　robot　spacecraft—Luna　9；　Mars　3；　Venera　8…on　other　worlds。

Apollo　conveyed　a　confidence；　energy；　and　breadth　of　vision　that　did　capture　the　imagination　of　the　world。　That　too　was　part　of　its　purpose。　It　inspired　an　optimism　about　technology；　an　enthusiasm　for　the　future。　If　we　could　fly　to　the　Moon；　as　so　many　have　asked；　what　else　were　we　capable　of？　Even　those　who　opposed　the　policies　and　actions　of　the　United　States—even　those　who　thought　the　worst　of　us—acknowledged　the　genius　and　heroism　of　the　Apollo　program。　With　Apollo；　the　United　States　touched　greatness。

When　you　pack　your　bags　for　a　big　trip；　you　never　know　what's　in　store　for　you。　The　Apollo　astronauts　on　their　way　to　and　from　the　Moon　photographed　their　home　planet。　It　was　a　natural　thing　to　do；　but　it　had　consequences　that　few　foresaw。　For　the　first　time；　the　inhabitants　of　Earth　could　see　their　world　from　above—the　whole　Earth；　the　Earth　in　color；　the　Earth　as　an　exquisite　spinning　white　and　blue　ball　set　against　the　vast　darkness　of　space。　Those　images　helped　awaken　our　slumbering　planetary　consciousness。　They　provide　incontestable　evidence　that　we　all　share　the　same　vulnerable　planet。　They　remind　us　of　what　is　important　and　what　is　not。　They　were　the　harbingers　of　Voyager's　pale　blue　dot。

We　may　have　found　that　perspective　just　in　time；　just　as　our　technology　threatens　the　habitability　of　our　world。　Whatever　the　reason　we　first　mustered　the　Apollo　program；　however　mired　it　was　in　Cold　War　nationalism　and　the　instruments　of　death；　the　inescapable　recognition　of　the　unity　and　fragility　of　the　Earth　is　its　clear　and　luminous　dividend；　the　unexpected　final　gift　of　Apollo。　What　began　in　deadly　petition　has　helped　us　to　see　that　global　cooperation　is　the　essential　precondition　for　of　survival。

Travel　is　broadening。

It's　time　to　hit　the　road　again。




CHAPTER　14　　　EXPLORING　OTHER　WORLDS　AND　PROTECTING　THIS　ONE

　

The　planets；　in　their　various　stages　of　development；　are　subjected　to　the　same　formative　forces　that　operate　on　our　earth；　and　have；　therefore；　the　same　geologic　formation；　and　probably　life；　of　our　own　past；　and　perhaps　future；　but。　further　than　this；　these　forces　are　acting；　in　some　cases；　under　totally　different　conditions　from　those　under　which　they　operate　on　the　earth；　and　hence　must　evolve　forms　different　from　those　ever　known　to　man。　The　value　of　such　material　as　this　to　the　parative　sciences　is　too　obvious　to　need　discussion。

—ROBERT　H。　GODDARD；　NOTEBOOK　（1907）

For　the　first　time　in　my　life；　I　saw　the　horizon　as　a　curved　line。　It　was　accentuated　by　a　thin　seam　of　dark　blue　light…our　atmosphere。　Obviously；　this　was　not　the　〃ocean〃　of　air　I　had　been　told　it　was　so　many　times　in　my　life。　I　was　terrified　by　its　fragile　appearance。

—ULF　MERBOLD；　GERMAN　SPACE　SHUTTLE　ASTRONAUT　（1988）

When　you　look　down　at　the　Earth　from　orbital　altitudes；　you　see　a　lovely；　fragile　world　embedded　in　black　vacuum。　But　peering　at　a　piece　of　the　Earth　through　a　spacecraft　porthole　is　nothing　like　the　joy　of　seeing　it　entire　against　the　backdrop　of　black；　or—better—sweeping　across　your　field　of　view　as　you　float　in　space　unencumbered　by　a　spacecraft。　The　first　human　to　have　this　experience　was　Alexei　Leonov；　who　on　March　18；　1965；　left　Voskhod　2　in　the　original　space　〃walk〃：　〃I　looked　down　at　the　Earth；〃　he　recalls；　〃and　the　first　thought　that　crossed　my　mind　was　‘The　world　is　round；　after　all。'　In　one　glance　I　could　see　from　Gibraltar　to　the　Caspian　Sea　。　。　。　I　felt　like　a　bird—with　wings；　and　able　to　fly。〃

When　you　view　the　Earth　from　farther　away；　as　the　Apollo　astronauts　did；　it　shrinks　in　apparent　size；　until　nothing　but　a　little　geography　remains。　You're　struck　by　how　self…contained　it　is。　An　occasional　hydrogen　atom　leaves；　a　pitter…patter　of　etary　dust　arrives。　Sunlight；　generated　in　the　immense；　silent　thermonuclear　engine　deep　in　the　solar　interior；　pours　out　of　the　Sun　in　all　directions；　and　the　Earth　intercepts　enough　of　it　to　provide　a　little　illumination　and　enough　heat　for　our　modest　purposes。　Apart　from　that；　this　small　world　is　on　its　own。

From　the　surface　of　the　Moon　you　can　see　it；　perhaps　as　a　crescent；　even　its　continents　now　indistinct。　And　from　the　vantage　point　of　the　outermost　planet　it　is　a　mere　point　of　pale　light。

From　Earth　orbit；　you　are　struck　by　the　tender　blue　arc　of　the　horizon—the　Earth's　thin　atmosphere　seen　tangentially。　You　can　understand　why　there　is　no　longer　such　a　thing　as　a　local　environmental　problem。　Molecules　are　stupid。　Industrial　poisons；　greenhouse　gases；　and　substances　that　attack　the　protective　ozone　layer；　because　of　their　abysmal　ignorance；　do　not　respect　borders。　They　are　oblivious　of　the　notion　of　national　sovereignty。　And　so；　due　to　the　almost　mythic　powers　of　our　technology　（and　the　prevalence　of　short…term　thinking）；　we　are　beginning—on　Continental　and　on　planetary　scales—to　pose　a　danger　to　ourselves。　Plainly；　if　these　problems　are　to　be　solved；　it　will　require　many　nations　acting　in　concert　over　many　years。

I'm　struck　again　by　the　irony　that　spaceflight—conceived　in　tile　cauldron　of　nationalist　rivalries　and　hatreds—brings　with　it　a　stunning　transnational　vision。　You　spend　even　a　little　time　contemplating　the　Earth　from　orbit　and　the　most　deeply　engrained　nationalisms　begin　to　erode。　They　seem　the　squabbles　of　mites　on　a　plum。

If　we're　stuck　on　one　world；　we're　limited　to　a　single　case；　we　don't　know　what　else　is　possible。　Then—like　an　art　fancier　familiar　only　with　Fayoum　tomb　paintings；　a　dentist　who　knows　only　molars；　a　philosopher　trained　merely　in　NeoPlatonism；　a　linguist　who　has　studied　only　Chinese；　or　a　physicist　whose　knowledge　of　gravity　is　restricted　to　falling　bodies　on　Earth—our　perspective　is　foreshortened；　our　insights　narrow；　our　predictive　abilities　circumscribed。　By　contrast；　when　we　explore　other　worlds；　what　once　seemed　the　only　way　a　planet　could　be　turns　out　to　be　somewhere　in　the　middle　range　of　a　vast　spectrum　of　possibilities。　When　we　look　at　those　other　worlds；　we　begin　to　understand　what　happens　when　we　have　too　much　of　one　thing　or　too　little　of　another。　We　learn　how　a　planet　can　go　wrong。　We　gain　a　new　understanding；　foreseen　by　the　spaceflight　pioneer　Robert　Goddard；　called　parative　planetology。

The　exploration　of　other　worlds　has　opened　our　eyes　in　the　study　of　volcanos；　earthquakes；　and　weather。　It　may　one　day　have　profound　implications　for　biology；　because　all　life　on　Earth　is　built　on　a　mon　biochemical　master　plan。　The　discovery　of　a　single　extraterrestrial　organism—even　something　as　humble　as　a　bacterium—would　revolutionize　our　understanding　of　living　things。　But　the　connection　between　exploring　other　worlds　and　protecting　this　one　is　most　evident　in　the　study　of　Earth's　climate　and　the　burgeoning　threat　to　that　climate　that　our　technology　poses。　Other　worlds　provide　vital　insights　about　what　dumb　things　not　to　do　on　Earth。

Three　potential　environmental　catastrophes—all　operating　on　a　global　scale—have　recently　been　uncovered：　ozone　layer　depletion；　greenhouse　warming；　and　nuclear　winter。　All　three　discoveries；　it　turns　out；　have　strong　ties　to　the　exploration　of　the　planets。

（1）　It　was　disturbing　to　find　that　an　inert　material　with　all　sorts　of　practical　applications—it　serves　as　the　working　fluid　in　refrigerators　and　air　conditioners；　as　aerosol　propellant　for　deodorants　and　other　products；　as　lightweight　foamy　packaging　for　fast　foods；　and　as　a　cleaning　agent　in　microelectronics；　to　name　only　a　few…can　pose　a　danger　to　life　on　Earth。　Who　would　have　figured？

The　molecules　in　question　are　called　chlorofluorocarbons　（CFCs）。　Chemically；　they're　extremely　inert；　which　means　they're　invulnerable—until　they　find　themselves　up　in　the　ozone　layer；　where　they're　broken　apart　by　ultraviolet　light　from　the　Sun。　The　chlorine　atoms　thus　liberated　attack　and　break　down　the　protective　ozone；　letting　more　ultraviolet　light　reach　the　ground。　This　increased　ultraviolet　intensity　ushers　in　a　ghastly　procession　of　potential　consequences　involving　not　just　skin　cancer　and　cataracts；　but　weakening　of　the　human　immune　system　and；　most　dangerous　of　all；　possible　harm　to　agriculture　and　to　photosynthetic　organisms　at　the　base　of　the　food　chain　on　which　most　life　on　Earth　depends。

Who　discovered　that　CFCs　posed　a　threat　to　the　ozone　layer？　Was　it　the　principal　manufacturer；　the　DuPont　Corporation；　exercising　corporate　responsibility？　Was　it　the　Environmental　Protection　Agency　protecting　us？　Was　it　the　Department　of　Defense　defending　us？　No；　it　was　two　Ivory…tower；　white…coated　university　scientists　working　on　something　else—Sherwood　Rowland　and　Mario　Molina　of　the　University　of　California；　Irvine。　Not　even　an　Ivy　League　university。　No　one　instructed　them　to　look　for　dangers　to　the　environment。　They　were　pursuing　fundamental　research。　They　were　scientists　following　their　own　interests。　Their　names　should　be　known　to　every　schoolchild。

In　their　original　calculations；　Rowland　and　Molina　used　rate　constants　of　chemical　reactions　involving　chlorine　and　other　halogens　that　had　been　measured　in　part　with　NASA