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1、DARKMATTERANDDARKENERGY∗MARCKAMIONKOWSKI†CaliforniaInstituteofTechnology,MailCode130-33,Pasadena,CA91125,USAThisisashortreview,aimedatageneralaudience,ofseveralcurrentsubjectsofresearchincosmology.Thetopicsdiscussedincludethecosmicmicrowavebackground(CMB),withparticularemphasi
2、sonitsrelevancefortestinginflation;darkmatter,withabriefreviewofastrophysicalevidenceandmoreemphasisonparticlecandidates;andcosmicaccelerationandsomeoftheideasthathavebeenputforwardtoexplainit.Aglossaryoftechnicaltermsandacronymsisprovided.1.IntroductionNowisthetimetobeacosmolo
3、gist.WehaveobtainedthroughremarkabletechnologicaladvancesandheroicandingeniousexperimentaleffortsadirectandextraordinarilydetailedpictureoftheearlyUniverseandmapsofthedistributionofmatteronthelargestscalesintheUniversetoday.Wehave,moreover,anelegantandpreciselyquantitativephysi
4、calmodelfortheoriginandevolutionoftheUniverse.However,themodelinvokesnewphysics,beyondthestandardmodelplusgeneralrelativity,notjustonce,butatleastthrice:(1)Inflation,thephysicalmechanismformakingtheearlyUniverselookpreciselyasitdoes,positssomenewultra-high-energyphysics;wedon’t
5、know,however,whatitis.(2)Thegrowthoflarge-scale-structureandthedynamicsofgalaxiesandgalaxyclustersrequiresthatweinvoketheexistenceofcollisionlessparticlesorobjects;wedon’tknowwhatthisstuffis.(3)TheacceleratedexpansionoftheUniverserequirestheintroductionofanewterm,ofembarrassing
6、lysmallvalue,inEinstein’sequation,amodificationofarXiv:0706.2986v1[astro-ph]20Jun2007generalrelativity,and/ortheintroductionofsomenegative-pressure“darkenergy,”again,thenatureofwhichremainsamystery.Inscience,though,confusionanduncertaintyareopportunity.Therearewell-definedbutfun
7、damentalquestionstobeansweredanddataarrivingtoguidetheory.Ongoingandforthcomingobservationsandexperimentswillinthenextfewyearsprovideempiricalinformationaboutthenewphysicsresponsibleforinflation,thenatureofthedarkmatter,andthepuzzleofacceleratedexpansion.Futurediscov-∗Submitted
8、forpublicationin“VisionsofDiscovery”(inhonorofCharlesTownes),