外研版初二下M1U2课件

外研版初二下课件M1U2本课件涵盖了外研版初二下单元的全部内容，包括宇宙、星系、太阳M1U2系以及探索太空等内容带你一起领略宇宙的奇妙之处！Lesson1:Our UniverseTheVastness of the TheBeauty ofNebulas TheMysteries ofBlackUniverse HolesNebulasare stunningcloudsThe universeis animmense of gas and dust wherenew Blackholes areincrediblyexpanse ofspace thatstars areborn.dense objectswith acontainscountless galaxies,gravitational forceso strongstars,and planets.that nothingcan escapethem,not evenlight.The Big Bang TheoryTheOrigin of the UniverseTheBig Bang Theory suggeststhat theuniverse beganas anextremely hotanddense pointand hasbeen expandingever since.Cosmic MicrowaveBackground RadiationThediscovery of cosmic microwavebackground radiationprovided strongevidencesupporting the BigBangTheory.The Expansionof SpaceScientistshave observedthat galaxiesare movingaway fromeach other,indicating theexpansion ofspace.Evidence forthe BigBang1Redshift ofGalaxiesThe redshiftof lightfrom distantgalaxies showsthat theyare movingawayfrom us,supporting theidea ofan expandinguniverse.2Abundance ofLight ElementsTheabundance oflight elements,such ashydrogen andhelium,in theuniverseis consistentwith thepredictions oftheBigBangTheory.3Uniform Distributionof CosmicBackground RadiationTheeven distributionofcosmicbackground radiationacross theentire skyindicatesan earlyhot anduniform universe.The HubbleTelescopeRevealing theUniverse TheHubble DeepField Repairand UpgradesTheHubble Space Telescope TheHubble DeepField Astronautshave visitedthehas providedstunning imagecaptured atiny HubbleSpaceTelescopetoimages andvaluable datapatch ofsky andrevealed repairand upgradeitsabout distantgalaxies andthousands ofgalaxies,instruments,extending itstheearly universe.showing thevastness ofthe scientificcapabilities.universe.The DifferentTypes ofGalaxiesSpiral GalaxiesElliptical GalaxiesIrregular GalaxiesSpiralgalaxies,like theElliptical galaxieshave aIrregular galaxieslack aMilky Way,have morerounded shape and definedshapeandoftendistinctive spiralarms and are madeup mostlyof oldresult fromgravitationalcontain amix ofyoung stars.interactions betweenandold stars.galaxies.The Milky Way1The Structureofthe Milky WayTheMilkyWayis abarred spiralgalaxy witha centralbulge,spiralarms,andadisk containingstars,gas,anddust.2Our SolarSystemOur solar system islocated withintheMilkyWay,about two-thirdsof theway fromthe centerto theouter edge.3The BlackHole atthe CenterAtthe centeroftheMilkyWaylies asupermassive black hole calledSagittariusA*,which hasa massof millionsof suns.The LifeCycle ofStars1Nebulae andStar FormationNebulaeare thebirthplaces ofstars.Stars formwhen gravityMainSequence Stars2causes thegas anddust in anebula tocollapse.Main sequencestars,like ourSun,fuse hydrogeninto heliumin their3Red Giantsand Supernovaecoresand arestable forbillions ofyears.As astar runsout ofhydrogen,itexpands into a redgiant andWhiteDwarfs,Neutron4eventually explodesina supernova,Stars,and BlackHoles scatteringheavy elementsintospace.Depending onits mass,theremnant ofasupernovacanbecome awhite dwarf,a neutronstar,or collapseintoablackhole.Lesson2:The SolarSystemThe Sun-Our TheTerrestrial TheGas GiantsStarPlanetsJupiter,Saturn,Uranus,and Neptuneare theTheSun isa massiveMercury,Venus,Earth,four gasgiant planetsballofgasthat providesand Marsare thefourlocated inthe outerheatand lightto therocky,inner planetsofregions ofthe solarplanetsin oursolar oursolarsystem.system.system.。