pale blue dot -carl sagan-第3部分

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Visit；　yes。　Settle；　not　yet。　Like　it　or　not；　for　the　moment　the　Earth　is　where　we　make　our　stand。

It　has　been　said　that　astronomy　is　a　humbling　and　character…building　experience。　There　is　perhaps　no　better　demonstration　of　the　folly　of　human　conceits　than　this　distant　image　of　our　tiny　world。　To　me；　it　underscores　our　responsibility　to　deal　more　kindly　with　one　another；　and　to　preserve　and　cherish　the　pale　blue　dot；　the　only　home　we've　ever　known。




CHAPTER　2　　　　ABBERATIONS　OF　LIGHT

　

　

If　man　were　taken　away　from　the　world；　the　rest　would　seem　to　be　all　astray；　without　aim　or　purpose　。　。　。　and　to　be　leading　to　nothing。

—FRANCIS　BACON；　WISDOM　OF　THE　ANCIENTS　（1619）

Ann　Druyan　suggests　an　experiment：　Look　back　again　at　the　pale　blue　dot　of　the　preceding　chapter。　Take　a　good　long　look　at　it。　Stare　at　the　dot　for　any　length　of　time　and　then　try　to　convince　yourself　that　God　created　the　whole　Universe　for　one　of　the　10　million　or　so　species　of　life　that　inhabit　that　speck　of　dust。　Now　take　it　a　step　further：　Imagine　that　everything　was　made　just　for　a　single　shade　of　that　species；　or　gender；　or　ethnic　or　religious　subdivision。　If　this　doesn't　strike　you　as　unlikely；　pick　another　dot。　Imagine　it　to　be　inhabited　by　a　different　form　of　intelligent　life。　They；　too；　cherish　the　notion　of　a　God　who　has　created　everything　for　their　benefit。　How　seriously　do　you　take　their　claim？



“SEE　THAT　STAR？〃　〃You　mean　the　bright　red　one？〃　his　daughter　asks　in　return。　〃Yes。　You　know；　it　might　not　be　there　anymore。　It　might　be　gone　by　now—exploded　or　something。　Its　light　is　still　crossing　space；　just　reaching　our　eyes　now。　But　we　don't　see　it　as　it　is。　We　see　it　as　it　was。〃

Many　people　experience　a　stirring　sense　of　wonder　when　they　first　confront　this　simple　truth。　Why？　Why　should　it　be　so　pelling？　On　our　little　world　light　travels；　for　all　practical　purposes；　instantaneously。　If　a　lightbulb　is　glowing；　then　of　course　it's　physically　where　we　see　it；　shining　away。　We　reach　out　our　hand　and　touch　it：　It's　there　all　right；　and　unpleasantly　hot。　If　the　filament　fails；　then　the　light　goes　out。　We　don't　see　it　in　the　same　place；　glowing；　illuminating　the　room　years　after　the　bulb　breaks　and　it's　removed　from　its　socket。　The　very　notion　seems　nonsensical。　But　if　we're　far　enough　away；　an　entire　sun　can　go　out　and　we'll　continue　to　see　it　shining　brightly；　we　won't　learn　of　its　death；　it　may　be；　for　ages　to　e—in　fact；　for　how　long　it　takes　light；　which　travels　fast　but　not　infinitely　fast；　to　cross　the　intervening　vastness。

The　immense　distances　to　the　stars　and　the　galaxies　mean　that　we　see　everything　in　space　in　the　past—some　as　they　were　before　the　Earth　came　to　be。　Telescopes　are　time　machines。　Long　ago；　when　an　early　galaxy　began　to　pour　light　out　into　the　surrounding　darkness；　no　witness　could　have　known　that　billions　of　years　later　some　remote　clumps　of　rock　and　metal；　ice　and　organic　molecules　would　fall　together　to　make　a　place　called　Earth；　or　that　life　would　arise　and　thinking　beings　evolve　who　would　one　day　capture　a　little　of　that　galactic　light；　and　try　to　puzzle　out　what　had　sent　it　on　its　way。

And　after　the　Earth　dies；　some　5　billion　years　from　now；　after　it　is　burned　to　a　crisp　or　even　swallowed　by　the　Sun；　there　will　be　other　worlds　and　stars　and　galaxies　ing　into　being—and　they　will　know　nothing　of　a　place　once　called　Earth。



IT　ALMOST　NEVER　FEELS　like　prejudice。　Instead；　it　seems　fitting　and　just—the　idea　that；　because　of　an　accident　of　birth；　our　group　（whichever　one　it　is）　should　have　a　central　position　in　the　social　universe。　Among　Pharaonic　princelings　and　Plantagenet　pretenders；　children　of　robber　barons　and　Central　mittee　bureaucrats；　street　gangs　and　conquerors　of　nations；　members　of　confident　majorities；　obscure　sects；　and　reviled　minorities；　this　self…serving　attitude　seems　as　natural　as　breathing。　It　draws　sustenance　from　the　same　psychic　wellsprings　as　sexism；　racism；　nationalism；　and　the　other　deadly　chauvinisms　that　plague　our　species。　Unmon　strength　of　character　is　needed　to　resist　the　blandishments　of　those　who　assure　us　that　we　have　an　obvious；　even　God…given；　superiority　over　our　fellows。　The　more　precarious　our　self…esteem；　the　greater　our　vulnerability　to　such　appeals。

Since　scientists　are　people；　it　is　not　surprising　that　parable　pretensions　have　insinuated　themselves　into　the　scientific　worldview。　Indeed；　many　of　the　central　debates　in　the　history　of　science　seem　to　be；　in　part　at　least；　contests　over　whether　humans　are　special。　Almost　always；　the　going…in　assumption　is　that　we　are　special。　After　the　premise　is　closely　examined；　though；　it　turns　out—in　dishearteningly　many　cases—that　we　are　not。

Our　ancestors　lived　out　of　doors。　They　were　as　familiar　with　the　night　sky　as　most　of　us　are　with　our　favorite　television　programs。　The　Sun；　the　Moon；　the　stars；　and　the　planets　all　rose　in　the　east　and　set　in　the　west；　traversing　the　sky　overhead　in　the　interim。　The　motion　of　the　heavenly　bodies　was　not　merely　a　diversion；　eliciting　a　reverential　nod　and　grunt；　it　was　the　only　way　to　tell　the　time　of　day　and　the　seasons。　For　hunters　and　gatherers；　as　well　as　for　agricultural　peoples；　knowing　about　the　sky　was　a　matter　of　life　and　death。

How　lucky　for　us　that　the　Sun；　the　Moon；　the　planets；　and　the　stars　are　part　of　some　elegantly　configured　cosmic　clockwork！　It　seemed　to　be　no　accident。　They　were　put　here　for　a　purpose；　for　our　benefit。　Who　else　makes　use　of　them？　What　else　are　they　good　for？

And　if　the　lights　in　the　sky　rise　and　set　around　us；　isn't　it　evident　that　we're　at　the　center　of　the　Universe？　These　celestial　bodies—so　clearly　suffused　with　unearthly　powers；　especially　the　Sun　on　which　we　depend　for　light　and　heat—circle　us　like　courtiers　fawning　on　a　king。　Even　if　we　had　not　already　guessed；　the　most　elementary　examination　of　the　heavens　reveals　that　we　are　special。　The　Universe　seems　designed　for　human　beings。　It's　difficult　to　contemplate　these　circumstances　without　experiencing　stirrings　of　pride　and　reassurance。　The　entire　Universe；　made　for　us！　We　must　really　be　something。

This　satisfying　demonstration　of　our　importance；　buttressed　by　daily　observations　of　the　heavens；　made　the　geocentrist　conceit　a　transcultural　truth—taught　in　the　schools；　built　into　the　language；　part　and　parcel　of　great　literature　and　sacred　scripture。　Dissenters　were　discouraged；　sometimes　with　torture　and　death。　It　is　no　wonder　that　for　the　vast　bulk　of　human　history；　no　one　questioned　it。

It　was　doubtless　the　view　of　our　foraging　and　hunting　ancestors。　The　great　astronomer　of　antiquity；　Claudius　Ptolemaeus　（Ptolemy）；　in　the　second　century　knew　that　the　Earth　was　a　sphere；　knew　that　its　size　was　〃a　point〃　pared　to　the　distance　of　the　stars；　and　taught　that　it　lay　〃right　in　the　middle　of　the　heavens。〃　Aristotle；　Plato；　St。　Augustine；　St。　Thomas　Aquinas；　and　almost　all　the　great　philosophers　and　scientists　of　all　cultures　over　the　3；000　years　ending　in　the　seventeenth　century　bought　into　this　delusion。　Some　busied　themselves　figuring　out　how　the　Sun；　the　Moon；　the　stars；　and　the　planets　could　be　cunningly　attached　to　perfectly　transparent；　crystalline　spheres—the　big　spheres；　of　course；　centered　on　the　Earth—that　would　explain　the　plex　motions　of　the　celestial　bodies　so　meticulously　chronicled　by　generations　of　astronomers。　And　they　succeeded：　With　later　modifications；　the　geocentric　hypothesis　adequately　accounted　for　the　facts　of　planetary　motion　as　known　in　the　second　century；　and　in　the　sixteenth。

From　there　it　was　only　a　slight　extrapolation　to　an　even　more　grandiose　claim—that　the　〃perfection〃　of　the　world　would　be　inplete　without　humans；　as　Plato　asserted　in　the　Timaeus。　〃Man　。　。　。　is　all；〃　the　poet　and　cleric　John　Donne　wrote　in　1625。　〃He　is　not　a　piece　of　the　world；　but　the　world　itself；　and　next　to　the　glory　of　God；　the　reason　why　there　is　a　world。〃

And　yet—never　mind　how　many　kings；　popes；　philosophers；　scientists；　and　poets　insisted　on　the　contrary—the　Earth　through　those　millennia　stubbornly　persisted　in　orbiting　the　Sun。　You　might　imagine　an　uncharitable　extraterrestrial　observer　looking　down　on　our　species　over　all　that　time—with　us　excitedly　chattering；　〃The　Universe　is　created　for　us！　We're　at　the　center！　Everything　pays　homage　to　us！〃—and　concluding　that　our　pretensions　are　amusing；　our　aspirations　pathetic；　that　this　must　be　the　planet　of　the　idiots。

But　such　a　judgment　is　too　harsh。　We　did　the　best　we　could。　There　was　an　unlucky　coincidence　between　everyday　appearances　and　our　secret　hopes。　We　tend　not　to　be　especially　critical　when　presented　with　evidence　that　seems　to　confirm　our　prejudices。　And　there　was　little　countervailing　evidence。

In　muted　counterpoint；　a　few　dissenting　voices；　counseling　humility　and　perspective；　could　be　heard　down　through　the　centuries。　At　the　dawn　of　science；　the　atomist　philosophers　of　ancient　Greece　and　Rome—　those　who　first　suggested　that　matter　is　made　of　atoms—Democritus；　Epicurus；　and　their　followers　（and　Lucretius；　the　first　popularizer　of　science）　scandalously　proposed　many　worlds　and　many　alien　life　forms；　all　made　of　the　same　kinds　of　atoms　as　we。　They　offered　for　our　consideration　infinities　in　space　and　time。　But　in　the　prevailing　canons　of　the　West；　secular　and　sacerdotal；　pagan　and　Christian；　atomist　ideas　were　reviled。　Instead；　the　heavens　were　not　at　all　like　our　world。　They　were　unalterable　and　〃perfect。〃　The　Earth　was　mutable　and　〃corrupt。〃　The　Roman　statesman　and　philosopher　Cicero　summarized　the　mon　view：　〃In　the　heavens　。　。　。　there　is　nothing　of　chance　or　hazard；　no　error；　no　frustration；　but　absolute　order；　accuracy；　calculation　and　regularity。〃

Philosophy　and　religion　cautioned　that　the　gods　（or　God）　were　far　more　powerful　than　we；　jealous　of　their　prerogatives　and　quick　to　mete　out　justice　for　insufferable　arrogance。　At　the　same　time；　these　disciplines　had　not　a　clue　that　their　own　teaching　of　how　the　Universe　is　ordered　was　a　conceit　and　a　delusion。

Philosophy　and　religion　presented　mere　opinion—opinion　that　might　be　overturned　by　observation　and　experiment—as　certainty。　This　worried　them　not　at　all。　That　some　of　their　deeply　held　beliefs　might　turn　out　to　be　mistakes　was　a　possibility　hardly　considered。　Doctrinal　humility　was　to　be　practiced　by　others。　Their　own　teachings　were　inerrant　and　Infallible。　In　truth；　they　had　better　reason　to　be　humble　than　they　knew。



BEGINNING　WITH　COPERNICUS　in　the　middle　sixteenth　century；　the　issue　was　formally　joined。　The　picture　of　the　Sun　rather　than　the　Earth　at　the　center　of　the　Universe　was　understood　to　be　dangerous。　Obligingly；　many　scholars　were　quick　to　assure　the　religious　hierarchy　that　this　newfangled　hypothesis　represented　no　serious　challenge　to　conventional　wisdom。　In　a　kind　of　split…brain　promise；　the　Sun…centered　system　was　treated　as　a　mere　putational　convenience；　not　an　astronomical　reality　that　is；　the　Earth　was　really　at　the　center　of　the　Universe；　as　everybody　knew；　but　if　you　wished　to　predict　where　Jupiter　would　be　on　the　second　Tuesday　of　November　the　year　after　next；　you　were　permitted　to　pretend　that　the　Sun　was　at　the　center。　Then　you　could　calculate　away　and　not　affront　the　Authorities。*

*　Copernicus'　famous　book　was　first　published　with　an　introduction　by　the　theologian　Andrew　Osiander；　inserted　without　the　knowledge　of　the　dying　astronomer。　Osiander's　well…meaning　attempt　to　reconcile　religion　and　Copernican　astronomy　ended　with　these　words：　〃＇L＇et　no　one　expect　anything　in　the　way　of　certainty　of　astronomy；　since　astronomy　can　offer　us　nothing　certain；　lest；　if　anyone　take　as　true　that　which　has　been　constructed　for　。mother　use；　he　go　away　from　this　discipline　a　bigger　fool　than　w　hen　he　cane　to　it。〃　Certainty　could　be　found　only　in　religion。

〃This　has　no　danger　in　it；〃　wrote　Robert　Cardinal　Bellarmine；　the　foremost　Vatican　theologian　in　the　early　seventeenth　century；　and　suffices　for　the　mathematicians。　But；　to　affirm　that　the　Sun　is　really　fixed　in　the　center　of　the　heavens　and　that　the　Earth　revolves　very　swiftly　around　the　Sun　is　a　dangerous　thing；　not　only　irritating　the　theologians　and　philosophers；　but　injuring　our　holy　faith　and　making　the　sacred　scripture　false。〃

〃Freedom　of　belief　is　pernicious；〃　Bellarmine　wrote　on　another　occasion。　〃It　is　nothing　but　the　freedom　to　be　wrong。〃

Besides；　if　the　Earth　was　going　around　the　Sun；　nearby　stars　should　seem　to　move　against　the　background　of　more　distant　stars　as；　every　six　months；　we　shift　our　perspective　from　one　side　of　the　Earth's　orbit　to　the　other。　No　such　〃annual　parallax〃　had　been　found。　The　Copernicans　argued　that　this　was　because　the　stars　were　extremely　far　away—maybe　a　million　times　more　distant　than　the　Earth　is　from　the　Sun。　Perhaps　better　telescopes；　in　future　times；　would　find　an　annual　parallax。　The　geocentrists　considered　this　a　desperate　attempt　to　save　a　flawed　hypothesis；　and　ludicrous　on　the　face　of　it。

When　Galileo　turned　the　first　astronomical　telescope　to　the　sky；　the　tide　began　to　turn。　He　discovered　that　Jupiter　had　a　little　retinue　of　moons　circling　it；　the　inner　ones　orbiting　faster　than　the　outer　ones；　just　as　Copernicus　had　deduced　for　the　motion　of　the　planets　about　the　Sun。　He　found　that　Mercury　and　Venus　went　through　phases　like　the　Moon　（showing　they　orbited　the　Sun）。　Moreover；　the　cratered　Moon　and　the　spotted　Sun　challenged　the　perfection　of　the　heavens。　This　may　in　part　constitute　the　sort　of　trouble　Tertullian　was　worried　about　thirteen　hundred　years　earlier；　when　he　pleaded；　〃If　you　have　any　sense　or　modesty；　have　done　with　prying　into　the　regions　of　the　sky；　into　the　destiny　and　secrets　of　the　universe。〃

In　contrast；　Galileo　taught　that　we　can　interrogate　Nature　by　observation　and　experiment。　Then；　〃facts　which　at　first　sight　seem　improbable　will；　even　on　scant　explanation；　drop　the　cloak　which　had　hidden　them　and　stand　forth　in　naked　and　simple　beauty。〃　Are　not　these　facts；　available　even　for　skeptics　to

confirm；　a　surer　insight　into　God's　Universe　than　all　the　speculations　of　the　theologians？　But　what　if　these　facts　contradict　the　beliefs　of　those　who　hold　their　religion　incapable　of　making　mistakes？　The　princes　of　the　Church　threatened　the　aged　astronomer　with　torture　if　he　persisted　in　teaching　the　abominable　doctrine　that　the　Earth　moved。　He　was　sentenced　to　a　kind　of　house　arrest　for　the　remainder　of　his　life。

A　generation　or　two　later；　by　the　time　Isaac　Newton　demonstrated　that　simple　and　elegant　physics　could　quantitatively　explain—and　predict—all　the　observed　lunar　and　planetary　motions　（provided　you　assumed　the　Sun　at　the　center　of　the　Solar　System）；　the　geocentrist　conceit　eroded　further。

In　1725；　in　an　attempt　to　discover　stellar　parallax；　the　painstaking　English　amateur　astronomer　James　Bradley　stumbled　on　the　aberration　of　light。　The　term　〃aberration；〃　I　suppose；　conveys　something　of　the　unexpectedness　of　the　discovery。　When　observed　over　the　course　of　a　year；　stars　were　found　to　trace　little　ellipses　against　the　sky。　But　all　the　stars　were　found　to　do　so。　This　could　not　be　stellar　parallax；　where　we　would　expect　a　big　parallax　for　nearby　stars　and　an　indetectible　one　for　faraway　stars。　Instead；　aberration　is　similar　to　how　raindrop　falling　directly　down　on　a　speeding　auto　seem　to　the　passen