solar system.ppt

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1、SolarSystemSpeaker:carolcontentStarPlanetandSatelliteCometExtra-terrestrialMilkywaygalaxy['ɡæləksi]SolarsystemHowmanyplanetinsolarsystemMercury['mə:kjuri]水星Venus['vi:nəs]金星Earth地球Mars火星Jupiter['dʒu:pitə]木星Saturn['sætən]土星Uranus['juərənəs]天王星Neptune['neptju:n]海王星Pluto['plu:təu]冥王星Plutoisnowconsi

2、deredadwarfplanetdwellingintheKuiperbelt.Neptune[‘neptju:n]海王星originManyscientiststhinkoursolarsystemformedfromagiant,rotatingcloudofgasanddustknownasthesolarnebula['nebjulə].Asthenebulacollapsedbecauseofitsgravity,itspunfasterandflattenedintoadisk.Mostofthematerialwaspulledtowardthecentertofor

3、mthesun.Otherparticleswithinthediskcollidedandstucktogethertoformasteroid-sizedobjectsnamedasplanetesimals[plænə'tesiməls],someofwhichcombinedtobecometheasteroids,comets,moonsandplanets.SolarSystemInnerSolarSystemInnerPlanets:Theinnerfourplanets—Mercury,Venus,EarthandMars—aremadeupmostlyofirona

4、ndrock.Theyareknownasterrestrial[ti'restriəl]orearthlikeplanetsbecauseoftheirsimilarsizeandcomposition.AsteroidbeltOuterSolarSystemOuterPlanetsCometsSolarsystemThesolarwindfromthesunwassopowerfulthatitsweptawaymostofthelighterelements,suchashydrogen[‘haidrədʒən]andhelium氦['hi:liəm],fromtheinner

5、mostplanets,leavingbehindmostlysmall,rockyworlds.Thesolarwindwasmuchweakerintheouterregions,however,resultingingasgiantsmadeupmostlyofhydrogenandhelium.SunThesunisbyfarthelargestobjectinoursolarsystem,containing99.8percentofthesolarsystem'smass.Itshedsmostoftheheatandlightthatmakeslifepossibleo

6、nEarthandpossiblyelsewhere.Planetsorbitthesuninoval-shapedpathscalledellipses[i'lipsiz],andthesunisslightlyofftothesideofthecenterofeachellipseConsistentofsunPhotospheresolarprominence['prɔminəns]日珥Corona[kə'rəunə]日冕totalsolareclipseMercuryVenusEarthcentrosphere['sentrəsfiə]mantle['mæntl]earthc

7、rustgeomagneticfieldperiodofrevolutionrotationrevolutionMars-222℃to30℃Celsius['selsiəs]degreeMarsfaceAgeofTeras['terəs]AsteroidbeltAsteroidbeltAsteroidsareminorplanets,mostofwhichcirclethesuninaregionknownastheasteroidbelt,between