stephen hawking - theory of everything

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1、GlobalKnowledgeFoundationTHETHEORYOFEVERYTHINGStephenHawkingThefollowingisasummaryofStephenHawking'stalkasprintedbyTheBulletinoftheUniversityofToronto.OnApril29,1980,IgavemyinaugurallectureastheLucasianProfessorofmathematicsatCambridge.Mytitlewas,IstheEndinSightforTheoreticalPhysics?Idescribed

2、theprogresswehadalreadymadeinthelasthundredyearsinunderstandingtheuniverseandaskedwhatthechanceswerethatwewouldfindacompleteunifiedtheoryofeverythingbytheendofthecentury.Well,theendofthecenturyisalmosthere.Althoughwehavecomealongway,particularlyinthelastthreeyears,itdoesn’tlookasifwearegoingto

3、quitemakeit.Inmy1980lectureIdescribedhowwehadbrokendowntheproblemoffindingatheoryofeverythingintoanumberofmoremanageableparts.Firstofallwehaddividedthedescriptionoftheuniversearoundusintotwoparts.Onepartisasetoflocallawsthattellushoweachregionoftheuniverseevolvesintime,ifweknowitsinitialstate,

4、andhowitisaffectedbyotherregions.Theotherpartisasetofwhatarecalledboundaryconditions.Thesespecifywhathappensattheedgeofspaceandtime.Theydeterminehowtheuniversebeginsand,maybe,howitends.Manypeople,includingprobablyamajorityofphysicists,feelthatthetaskoftheoreticalphysicsshouldbeconfinedtothefir

5、stpart,thatofformulatinglocallawsthatdescribehowtheuniverseevolvesintime.Theywouldregardthequestionofhowtheinitialstateisdeterminedasbeingbeyondthescopeofphysicsandbelongingtotherealmsofmetaphysicsorreligion.ButI’manunashamedrationalist.Inmyopiniontheboundaryconditionsoftheuniversethatdetermin

6、eitsinitialstateareaslegitimateamatterforscientificinquiryasarethelawsthatgovernhowitevolves.Intheearly1960stheforcesthatwereknowntophysicswereclassifiedintofourcategoriesthatseemedtobeseparateandindependentofeachother.Thefirstofthefourcategorieswasthegravitationalforce,whichiscarriedbyapartic

7、lecalledthegraviton.Gravityisbyfartheweakestofthefourforces.However,itmakesupforitslowstrengthbyhavingtwoimportantproperties.Thefirstisthatitisuniversal.Thatis,itaffectseveryparticleintheuniverseinthesameway.Allbodiesareattractedtoeacho