2024剑桥雅思讲义Reading_Test_1.docx

ZQ国国PaSSage1TheLayersoftheSunConsidertheearth,themoon,andalltheotherplanetsinoursolarsystem.Thinkaboutthemassthatallthoseobjectsmusthavewhentheyarealladdedtogether.Counter-intuitively,addedalltogethertheyaccountforonly0.2%ofthetotalmassofthesolarsystem.Thesunmakesuptheremaining99.8%ofallthemassinthesolarsystem!Thesunisthecenterofthesolarsystemandthelargestobjectinthesolarsystem.OursunisastarthatprovideslightandheatandsupportsalmostalllifeonEarth.Thesunisasphere,butunliketheearthandthemoon,itisnotsolid.Mostatomsinthesunexistasplasma,orafourthstateofmattermadeupofsuperheatedgaswithanelectricalcharge.Oursunconsistsalmostentirelyoftheelementshydrogenandhelium,andbecausethesunisnotsolidzitdoesnothaveadefinedouterboundary.Itdoes,howevehaveadefiniteinternalstructure.Thereareseveralidentifiablelayersofthesun:Thecoreistheinnermostorcentrallayerofthesun.Thecoreisplasma,butmovessimilarlytoagas.Itstemperatureisaround27milliondegreesCelsius.Inthecore,nuclearreactionscombinehydrogenatomstoformhelium,releasingvastamountsofenergyintheprocess.Theenergyreleasedthenbeginstomoveoutward,towardstheouterlayersofthesun.Justoutsidethecoreistheradiativezone,whichhasatemperatureofabout7milliondegreesCelsius.Theenergyreleasedinthecoretravelsextremelyslowlythroughtheradiativezone.Particlesoflightcalledphotonscanonlytravelafewmillimetersbeforetheyhitanotherparticleinthesun,areabsorbedandthenreleasedagain.Itcantakeaphotonaslongas50millionyearstotravelallthewaythroughtheradiativezone.Surroundingtheradiativezoneistheconvectionzone.Here,hotmaterialfromnearthesun'scenterrises,coolsatthesurface,andthenplungesbackdownwardtoreceivemoreheatfromtheradiativezone.Thismovementhelpstocreatesolarflaresandsunspots.Thesefirstthreelayersmakeupwhatwewouldactuallycall"thesun".Thenextthreelayersmakeupthesun'satmosphere.Ofcourse,therearenosolidlayerstoanypartofthesun,sotheseboundariesarefuzzyandindistinct.Thevisiblesurfaceofthesunisknownasthephotosphere.Thisistheregionofthesunthatemitssunlight.It'salsooneofthecoolestlayersofthesunonlyabout6700oC.Lookingataphotographofthesun'ssurface,youcanseethatithasseveraldifferentcolors:oranges,yellowandreds,givingitagrainyappearance.Wecannotseethiswhenweglancequicklyatthesunasoureyescan'tfocusthatquicklyandthesunistoobrightforustolookatformorethanabriefmoment.Lookingatthesunforanylengthoftimecancauseblindness,sodon'ttryit!Sunlightisemittedfromthesun'sphotosphere.AfractionofthelightthattravelsfromthesunreachesEarth.Ittravelsaslightinarangeofwavelengths,includingvisiblelight,ultravioletandinfraredradiation.Visiblelightisallthelightwecanseewithoureyes.Wecan'tseeultravioletorinfraredradiation,buttheireffectscanQD国IELTSADVANTAGEstillbedetected.Forexample,sunburniscausedbyultravioletradiationwhenyouspendtoomuchtimeinthesun.Thechromosphereisthezoneabout2,000kilometersthickthatliesdirectlyabovethephotosphere.Thechromosphereisathinregionofthesun'satmospherethatglowsredasitisheatedbyenergyfromthephotosphere.Temperaturesinthechromosphererangefromabout4000oCtoabout10z000oC.Jetsofgasfireupthroughthechromosphereatspeedsupto72,000kilometersperhour,reachingheightsashighas10,000kilometers.Theoutermostlayerofthesun,andtheoutermostpartofitsatmosphere,iscalledthecorona.Itisthesun'shaloor"crown".Ithasatemperatureof2to5milliondegreesCelsiusandismuchhotterthanthevisiblesurfaceofthesun,orphotosphere.Thecoronaextendsmillionsofkilometersintospace.Ifyoueverhavethechancetoseeatotalsolareclipse,youwillbeabletoseethesun'scorona,shiningoutintospace.Toconclude,inthesun'score,nuclearfusionreactionsgenerateenergybyconvertinghydrogentohelium,andtherestofthesunisheatedbythemovementofthisenergyoutwardfromthecore.Lightenergyfromthesunisemittedfromthephotosphere,andittravelsthroughspace,andsomeofitreachestheearth.ThesunisthesourceofalmostalltheenergyonEarthandsunlightpowersphotosynthesis,aswellaswarmingandilluminatingourEarth.Adaptedfrom:https:en.wikibooks.ora/Wiki/HiahSChOOlEarthSCienCe/TheSUnQD国后Questions1-4LabelthediagrambelowWiththenamesofthelayersofthesun.ChooseNOMORETHANTWOWORDSfromthereadingpassageforeachanswer.Afteryou,vetriedthesequestions,checkyouranswerswiththefollowingvideo.Questions5-9CompleteeachsentencewiththecorrectendingA-Ifromtheboxbelow.WritethecorrectletterA-Iinboxes5-9onyouranswersheet.NBnotallletterswillbeused.S. Thevastmajorityofthetotalmassofthesolarsystemisaccountedforby.T. Thereisnofixedouteredge.U. Thecoreproducesenergywhich.O.Ourplanetonlyreceives.Q.Onekindoflightemittedbythesun,which.A.canbeseeninthephotosphere,isaformOfsuperheatedgas.V. isextremelyhotandusedtocreatehydrogen.W. isinvisibletohumanszcandamageourskin.X. movesataveryslowpacethroughtheareasurroundingit.Y. asmallproportionofthelightwhichthesunemits.Z. sunspots,whicharethethirdlayerofthesunzsatmosphere.AA. thebiggestsingleobjectinthesolarsystem,whichisthesun.BB. theplanetsandtheirmoons.CC. tothesunduetothefactthatitismo