大学英语精读第6册课文全文翻译中英对照Word格式文档下载.docx

大学英语精读第6册课文全文翻译中英对照Word格式文档下载.docx

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Throughallofourhistorywehaveponderedthestarsandmusedwhetherhumanityisuniqueorif,somewhereelseinthedarkofthenightsky,thereareotherbeingswhocontemplateandwonderaswedo,fellowthinkersinthecosmos.Suchbeingsmightviewthemselvesandtheuniversedifferently.Somewhereelsetheremightbeveryexoticbiologiesandtechnologiesandsocieties.Inacosmicsettingvastandoldbeyondordinaryhumanunderstanding,wearealittlelonely;

andwepondertheultimatesignificance,ifany,ofourtinybutexquisiteblueplanet.

Thesearchforextraterrestrialintelligenceisthesearchforagenerallyacceptablecosmiccontextforthehumanspecies.Inthedeepestsense,thesearchforextraterrestrialintelligenceisasearchforourselves.

Inthelastfewyears--inone-millionththelifetimeofourspeciesonthisplanet--wehaveachievedanextraordinarytechnologicalcapabilitywhichenablesustoseekoutunimaginablydistantcivilizationseveniftheyarenomoreadvancedthanwe.Thatcapabilityiscalledradioastronomyandinvolvessingleradiotelescopes,collectionsorarraysofradiotelescopes,sensitiveradiodetectors,advancedcomputersforprocessingreceiveddate,andtheimaginationandskillofdedicatedscientists.Radioastronomyhasinthelastdecadeopenedanewwindowonthephysicaluniverse.Itmayalso,ifwearewiseenoughtomaketheeffort,castaprofoundlightonthebiologicaluniverse.

Somescientistsworkingonthequestionofextraterrestrialintelligence,myselfamongthem,haveattemptedtoestimatethenumberofadvancedtechnicalcivilizations--definedoperationallyassocietiescapableofradioastronomy--intheMilkyWayGalaxy.Suchestimatesarelittlebetterthanguesses.Theyrequireassigningnumericalvaluestoquantitiessuchasthenumbersandagesofstars;

theabundanceofplanetarysystemsandthelikelihoodoftheoriginoflife,whichweknowlesswell;

andtheprobabilityoftheevolutionofintelligentlifeandthelifetimeoftechnicalcivilizations,aboutwhichweknowverylittleindeed.

Whenwedothearithmetic,thesortsofnumberswecomeupwithare,characteristically,aroundamilliontechnicalcivilizations.Amillioncivilizationsisabreathtakinglylargenumber,anditisexhilaratingtoimaginethediversity,lifestylesandcommerceofthosemillionworlds.ButtheMilkyWayGalaxycontainssome250billionstars,andevenwithamillioncivilizations,lessthanonestarin200,000wouldhaveaplanetinhabitedbyanadvancedcivilization.Sincewehavelittleideawhichstarsarelikelycandidates,wewillhavetoexamineaverylargenumberofthem.Suchconsiderationssuggestthatthequestforextraterrestrialintelligencemayrequireasignificanteffort.

Despiteclaimsaboutancientastronautsandunidentifiedflyingobjects,thereisnofirmevidenceforpastvisitationoftheEarthbyothercivilizations.Wearerestrictedtoremotesignalingand,ofthelong-distancetechniquesavailabletoourtechnology,radioisbyfarthebest.Radiotelescopesarerelativelyinexpensive;

radiosignalstravelatthespeedoflight,fasterthanwhichnothingcango;

andtheuseofradioforcommunicationisnotashort-sightedoranthropocentricactivity.RadiorepresentsalargepartoftheelectromagneticspectrumandanytechnicalcivilizationanywhereintheGalaxywillhavediscoveredradioearly--justasinthelastfewcenturieswehaveexploredtheentireelectromagneticspectrumfromshortgammaraystoverylongradiowaves.Advancedcivilizationsmightverywellusesomeothermeansofcommunicationwiththeirpeers.Butiftheywishtocommunicatewithbackwardoremergingcivilizations,thereareonlyafewobviousmethods,thechiefofwhichisradio.

ThefirstseriousattempttolistenforpossibleradiosignalsfromothercivilizationswascarriedoutattheNationalRadioAstronomyObservatoryinGreenbank,WestVirginia,in1959and1960.ItwasorganizedbyFrankDrake,nowatCornelUniversity,andwascalledProjectOzma,aftertheprincessoftheLandofOz,aplaceveryexotic,verydistantandverydifficulttoreach.Drakeexaminedtwonearbystarsforafewweekswithnegativeresults.Positiveresultswouldhavebeenastonishingbecauseaswehaveseen,evenratheroptimisticestimatesofthenumberoftechnicalcivilizationsintheGalaxyimplythatseveralhundredthousandstarsmustbeexaminedinordertoachievesuccessbyrandomstellarselection.

SinceProjectOzma,therehavebeensixoreightothersuchprograms,allatarathermodestlevel,intheUnitedStates,CanadaandtheSovietUnion.Allresultshavebeennegative.Thetotalnumberofindividualstarsexaminedtodateinthiswayislessthanathousand.Wehaveperformedsomethinglikeonetenthofonepercentoftherequiredeffort.

However,therearesignsthatmuchmoreseriouseffortsmaybemusteredinthereasonablynearfuture.Besides,handinhandwiththerecentspectacularadvancesinradiotechnology,therehasbeenadramaticincreaseinthescientificandpublicrespectabilityoftheentiresubjectofextraterrestriallife.AclearsignofthenewattitudeistheVikingmissionstoMars,whicharetoasignificantextentdedicatedtothesearchforlifeonanotherplanet.

Butalongwiththeburgeoningdedicationtoaserioussearch,aslightlynegativenotehasemergedwhichisneverthelessveryinteresting.Afewscientistshavelatelyaskedacuriousquestion:

Ifextraterrestrialintelligenceisabundant,whyhavewenotalreadyseenitsmanifestations?

SkepticsalsoaskwhythereisnoclearevidenceofextraterrestrialvisitstoEarth.Wehavealreadylaunchedslowandmodestinterstellarspacecraft.Asocietymoreadvancethanoursshouldbeabletoplythespacesbetweenthestarsconvenientlyifnoteffortlessly.Overmillionsofyearssuchsocietiesshouldhaveestablishedcolonies,whichmightthemselveslaunchinterstellarexpeditions.Whyaretheynothere?

Thetemptationistodeducethatthereareatmostafewadvancedextraterrestrialcivilizations--eitherbecausestatisticallyweareoneofthefirsttechnicalcivilizationstohaveemergedorbecauseitisthefateofallsuchcivilizationstodestroythemselvesbeforetheyaremuchfurtheralongthanwe.

Itseemstomethatsuchdespairisquitepremature.Allsuchargumentsdependonourcorrectlysurmisingtheintentionsofbeingsfarmoreadvancedthanourselves,andwhenexaminedmorecloselyIthinktheseargumentsrevealarangeofinterestinghumanconceits.Whydoweexpectthatitwillbeeasytorecognizethemanifestationsofveryadvancedcivilizations?

IsoursituationnotclosertothatofmembersofanisolatedsocietyintheAmazonbasin,say,wholackthetoolstodetectthepowerfulinternationalradioandtelevisiontrafficthatisallaroundthem?

Also,thereisawiderangeofincompletelyunderstoodphenomenainastronomy.Mightthemodulationofpulsarsortheenergysourceofquasars,forexample,haveatechnologicalorigin?

Orperhapsthereisagalacticethicofnoninterferencewithbackwardoremergingcivilizations.Perhapsthereisawaitingtimebeforecontactisconsideredappropriate,soastogiveusafairopportunitytodestroyourselvesfirst,ifwearesoinclined.Perhapsallsocietiessignificantlymoreadvancedthanourownhaveachievedaneffectivepersonalimmortalityandlosethemotivationforinterstellargallivanting,whichmay,forallweknow,beatypicalurgeonlyofadolescentcivilizations.Perhapsmaturecivilizationsdonotwishtopollutethecosmos.Thereisaverylonglistofsuch"

perhaps,"

fewofwhichweareinapositiontoevaluatewithanydegreeofassurance.

Thequestionofextraterrestrialcivilizationsseemstomeentirelyopen.Personally,Ithinkitfarmoredifficulttounderstandauniverseinwhichwearetheonlytechnologicalcivilization,oroneofaveryfew,thantoconceiveofacosmosbriningoverwithintelligentlife.Manyaspectsoftheproblemare,fortunately,amenabletoexperimentalverification.Wecansearchforplanetsofotherstars,seeksimpleformsoflifeonsuchnearbyplanetsasMars,andperformmoreextensivelaboratorystudiesonthechemistryoftheoriginoflife.Wecaninvestigatemoredeeplytheevolutionoforganismsandsocieties.Theproblemcriesoutforalong-term,open-minded,systematicsearch,withnatureastheonlyarbiterofwhatisorisnotlikely.

THELIBRARYCARD

OnemorningIarrivedearlyatworkandwentintothebanklobbywheretheNegroporterwasmopping.IstoodatacounterandpickeduptheMemphisCommercialAppealandbeganmyfreereadingofthepress.IcamefinallytotheeditorialpageandsawanarticledealingwithoneH.L.Mencken.IknewbyhearsaythathewastheeditoroftheAmericanMercury,butasidefromthatIknewnothingabouthim.ThearticlewasafuriousdenunciationofMencken,concludingwithone,hot,shortsentence:

Menckenisafool.

IwonderedwhatonearththisMenckenhaddonetocalldownuponhimthescornoftheSouth.TheonlypeopleIhadeverheardenouncedintheSouthwereNegroes,andthismanwasnotaNegro.ThenwhatideasdidMenckenholdthatmadeanewspaperliketheCommercialAppealcastigatehimpublicly?

UndoubtedlyhemustbeadvocatingideasthattheSouthdidnotlike.

Now,howcouldIfindoutaboutthisMencken?

Therewasahugelibraryneartheriverfront,butIknewthatNegroeswerenotallowedtopatronizeitsshelvesanymorethantheyweretheparksandplaygroundsofthecity.Ihadgoneintothelibraryseveraltimestogetbooksforthewhitemenonthejob.Whichofthemwouldnowhelpmetogetbooks?

Iweighedthepersonalit