地球科学Earth Science

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1、EarthScienceEarthscienceisthestudyofearthasaplanetandhowitinteractsandrelatestocetestialobjects.CelestialObjects-otherobjectsinspace.Thestudyofearthsciencehasevolvedgreatlyoverthelast100yearsorso,butonlyrecentlyhasbecomeastrandofscienceallonitsowncalled“earthsystemscience”.Weno

2、wknowthattheearthisnotasrandaloneplanet,butitinteractswiththesolarsystemandtheuniversearoundit.Techologyisbecomingmoreadvancedwhichmeanswecantravel,furtherdeeperandunderstandmorethanweeverhavebefore.SystemAsystemnislikeamodel,whichcanbeefinedaspartoftheuniverseandcanbestudiedse

3、parately.ClosedandopensystemWhat’sthedifference?Inacloedsystem,energy(likesunlightforexample)cangetin,butmatterdoesn’tenterorleave.Inanopensystemthesystemandit’ssurroundingsfreelyexchangeBothmatterandenergy.PlanetaryOneoftheconsequencesofhavinganassentialltclosedsystemisthatmos

4、tofourresourcesarefinite.EnergyCycleImcomingsolarenergy100%Reflectedbyatmosphere6%Reflectedbyclouds20%Reflectedfromearth’ssurface4%Absorbedbylandandoceans51%Conductionandrisingair7%Absorbedbyclouds3%Absorbedbyatmosphere16%Radiatedtospacefromcloudsandatmosphere64%Radiateddirectl

5、ytospacefromearthRadiationabsorbedbyatmosphere15%Carriedtocloudsandatmopherebylatentheatinwatervapor23%GreenlandXSRRAMGCGOriginoftheuniverseImportanceoftimescales.Forcesatworkinthepast-somechangesasplanetevolved.Forcesatworktoday.Howcanwemeasureageoftheearth.HowoldisEarth?Bibli

6、calscholarsof19thcentury(BishopUssher)-600years(Startedat4004BC)ClassicalGreeks-infinite-historyendlesslyrepeatsitself.Mayansbelievedearthrecycledona3000yearstimescaleHanChinesethoughtearthwasrecreatedevery2369040yearsTheagewenowexceptmaychangebutisconsistentwithcurrenttheory.M

7、orerecenteffortsLordKelvin:80millionyearsold-basedoncoolingofmoltenearth.Darwin:reallyoldbasedontimefornaturalselection(biologicalargument)Hutton:reallyoldbasedonuniformitarianism(Processesinthepasttakingplaceatratescomparabletotoday)(Geologicalargument)Earth’sageEarthisabout4.

8、5(or4.6)BYold.First700MYearthwasaspinningcloudofgas,du