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1、LifeintheUniverseInthistalk,Iwouldliketospeculatealittle,onthedevelopmentoflifeintheuniverse,andinparticular,thedevelopmentofintelligentlife.Ishalltakethistoincludethehumanrace,eventhoughmuchofitsbehaviourthroughouthistory,hasbeenprettystupid,andnotcalculatedtoaidthesurvivalofthespecies.Twoquesti
2、onsIshalldiscussare,'Whatistheprobabilityoflifeexistingelsewhereintheuniverse?'and,'Howmaylifedevelopinthefuture?'Itisamatterofcommonexperience,thatthingsgetmoredisorderedandchaoticwithtime.Thisobservationcanbeelevatedtothestatusofalaw,theso-calledSecondLawofThermodynamics.Thissaysthatthetotalamo
3、untofdisorder,orentropy,intheuniverse,alwaysincreaseswithtime.However,theLawrefersonlytothetotalamountofdisorder.Theorderinonebodycanincrease,providedthattheamountofdisorderinitssurroundingsincreasesbyagreateramount.Thisiswhathappensinalivingbeing.OnecandefineLifetobeanorderedsystemthatcansustain
4、itselfagainstthetendencytodisorder,andcanreproduceitself.Thatis,itcanmakesimilar,butindependent,orderedsystems.Todothesethings,thesystemmustconvertenergyinsomeorderedform,likefood,sunlight,orelectricpower,intodisorderedenergy,intheformofheat.Inthisway,thesystemcansatisfytherequirementthatthetotal
5、amountofdisorderincreases,while,atthesametime,increasingtheorderinitselfanditsoffspring.Alivingbeingusuallyhastwoelements:asetofinstructionsthattellthesystemhowtosustainandreproduceitself,andamechanismtocarryouttheinstructions.Inbiology,thesetwopartsarecalledgenesandmetabolism.Butitisworthemphasi
6、singthatthereneedbenothingbiologicalaboutthem.Forexample,acomputervirusisaprogramthatwillmakecopiesofitselfinthememoryofacomputer,andwilltransferitselftoothercomputers.Thusitfitsthedefinitionofalivingsystem,thatIhavegiven.Likeabiologicalvirus,itisaratherdegenerateform,becauseitcontainsonlyinstruc
7、tionsorgenes,anddoesn'thaveanymetabolismofitsown.Instead,itreprogramsthemetabolismofthehostcomputer,orcell.Somepeoplehavequestionedwhethervirusesshouldcountaslife,becausetheyareparasites,andcannotexistindependentlyofth
