英语翻译Forthepast50years,scientistshavescouredtheskiesforradiosignalsfrombeyondourplanet,hopingforsomesignofextraterrestriallife.Butonephysicistsaysthere'snoreasonalienlifecouldn'talreadybeexistingamongus—or

　　英语翻译

　　Forthepast50years,scientistshavescouredtheskiesforradiosignalsfrombeyondourplanet,hopingforsomesignofextraterrestriallife.Butonephysicistsaysthere'snoreasonalienlifecouldn'talreadybeexistingamongus—ormaybeeveninus.

　　PaulDavies,anaward-winningArizonaStateUniversityphysicistknownforhispopularsciencewritingsaidTuesdaythatlifemayhavedevelopedonEarthnotoncebutseveraltimes.

　　Daviessaidthevariantlifeforms-mostlikelytinymicrobes—couldstillbehangingaround"rightunderournoses-oreveninournoses."

　　"Howdoweknowalllifeonearthdescendedfromasingleorigin?"hetoldaconferenceatLondon'sprestigiousRoyalSociety,whichservesasBritain'sacademyofsciences."We'vejustscratchedthesurfaceofthemicrobialworld."

　　Unusualorganismsabound-includingchemical-eatingbacteriawhichhideoutdeepintheoceanandorganismsthatthriveinboiling-hotsprings—butthatdoesn'tmeanthey'redifferentlifeformsentirely.

　　"Howweirddotheyhavetobesuggestedasecondgenesisasopposedtojustanobscurebranchofthefamilytree?"hesaidCoolingfan.Daviessuggestedthattheonlywaytoproveanorganismwasn't"lifeasweknowit"wasifitwerebuiltusingexoticelementswhichnootherformoflifehad.

　　Suchorganismshaveyettobefound.Daviesalsonotedthatlessthan1percentofalltheworld'sbacteriahadbeencomprehensivelystudiedChiironleavingplentyoftimetofindunusualorganisms.