L10 - MarsRoverMissionsareincredibly cheapandefficient!

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Unformatted text preview: MarsRoverMissionsareincredibly cheapandefficient! Whathappenedsince1990? ReviewonLecture69 1.Exoplanets:DetecEonMethods(Chap4) GravitaEonalLensing AstrometricMeasurement(angulardistance) TransitMethod 2.SolarSystem(Chap48) GeneralProperEes(members,orbits,formaEon) EarthMoonSystem Terrestrial&GaseousPlanets Exoplanets:DetecEonMethods Gravitybendsspace! Asresults, Sharpincreaseinbrightness Changesintheapparent posiEon AstrometricMeasurementistheoldestmethod usedinsearchingforexoplanets. PlanetTransit: PlanetblocksoutaEnyporEonofstar'slight,thusreducing itsapparentbrightness AstrometricMeasurement d s introducingradian s/2d=/360 360=2rad s/d= AstrometricMeasurement Example2 TheangularsizesoftheSunandtheMoonin theskyareaboutahalfdegree(0.5).Butthe truesizeoftheSunisabout400Emesbigger thanthetruesizeoftheMoon.Thenhowfar istheMoonfromEarth? Answer=400EmesclosertoEarththantheSun SolarSystem 8kpc lyr SolarSystemScale&Layout(1) 30AU 100AU 105AU Launchedin1977 V=20,000m/s AsofAug2006 OortCloudisahypotheEcalshellwhichiscomposedofnumerous cometlikebodies. GeneralProperEesofSolarSystem Aboutmembers Sunisthegoverningbodyofthesolarsystem! Over99%ofmassoftheSolarSystemis intheSun. Hydrogen(75%)+Helium(24%)+ otherelements(lessthan1%) Twomajormembers 1)Earthlike,smallrockyplanets 2)Jupiterlike,biggaseousplanets Twosubmembers 1)Interplanetarydebris(asteroid, comets,meteors) 2)Dwarfplanets(Plutolike) GeneralProperEesofSolarSystem SmallerbodiesSolarSystemDebris Sizerangesfrompebblesizetofew hundredkm Rocky(iron,silicate,nickel...etc)& icymaterials Randomshapesexceptdwarf planets(relaEvelymassivebodies) Bumpysurfaceduetonumerous eventsofimpacts >>What'stheimplica3on? GeneralProperEesofSolarSystem AboutOrbits TheirorbitalmoEonscanbe describedbyKepler's planetarymoEons. 1)Theorbitalshapesof these8arenearlycircular 2)Alltheplanetsorbitthe SuninthesamedirecEon 3)Theorbitalplanesarein nearlythesameplaneas Earth's **WhataboutPluto& Comets? Let'sputthesealtogether!Solar SystemFormaEonScenario OurSolarsystemappearstobeverywellarchitectedbyahighdegree oforderwithafewexcepEons. 1)IngredientsHydrogen,Helium,rocks&ice 2)BrutalcondiEonsSmallrockswithbumpysurface, irregularshapes 3)OrbitalmoEonsareconsistentMomentumconservaEon nearlycircularshapes samedirecEon nearlyinthesameplane thesealsoapplytothemoEonsofthemoons BasedontheseinformaEon,Astronomerscameupwithatheoryofthe SolarsystemformaEon lot'sofgas dense&caoEcenvironment rotateinconsistentway FormaEonof theSolarSystem: NebularTheory ItallstartsfromStars... 1)StellarwindsorSNe 2)Interstellardust,condensaEon 3)GiantMolecularCloud 4)GravitaEonalContracEon 5)RotaEonbytheconservaEon oftheangularmomentum 6)Protostellardisk Whathappens intheprotostellar disk? 1)AccreEon >>"Planetesimals" >>"Protoplanets" >>Planets 2)Collisions& FragmentaEon >>asteroids&comets 3)Innerregion:metallic core+rockyenvelop outerregions:icycore+ gaseousenvelop This Nebular Theory seems to explain almost every aspects of the Solar systemfairlywell. So... is the Nebular Theory a good theory? Does it also can describe the general properEesoftheexoplanets? Earth:OverallStructure 6mainlayersofEarth 1)MetallicCores(ironcore) 2)Mantle(Silicatemantle) 3)Crust 4)Atmosphere 5)Trophosphere 6)Magnetosphere Moon:Structure Howthesmoothsurface (Maria)formed? EarthCores:SeismicWaves EarthCores:DifferenEaEon Heaviermaterialstendtosinkwhilelightermaterialslikelyfloat! Asaresult? EarthMantle&Crust: HalfmoltenplasEcuppermantle movesduetoconvecEon. EarthconEnents(plate)aredriving overthisplasEcmantle. Asaresult? EarthAtmosphere: IsGlobalWarmingjustafluke? Earthsurfacetemperaturekeeps increasingduetohumanacEviEes? FamousGlobalWarmingSkepEcs Dr.FredrickSeitz Dr.RichardS.Lindzen Dr.SFredSinger Dr.PatrickJ.Michaels Dr.RobertC.BallingJr StudyingMoon:Landscape EarthlikeTerrestrialPlanets Mercury,Venus,&Mars JupiterlikeGaseousPlanets KeyConceptsforSolarPlanets RecallthecondiEonsintheearlyenvironment! 1)Oncealloftherockyplanetswereveryhot&mostlymolten (plasEclikestate):differenciaEon 2)Allofthegaseousplanetshaveicycoressurroundedby metallic(Jupiter,Saturn)oricyliquid(Uranus,Neptune) hydrogen&helium 3)Size&DistancefromtheSunwerethecrucial forthedifferencesbetweentherockyplanets 4)Rememberyourreferenceplanet!:Earth Mercury BasicInformaEon P=88days,withahighlyeccentric 3:2spinorbitresonance R=2400km d=0.4AU =5400kg/m3 T~400C(~752F)ondayEmeside ~170Connightside Unusualwrinklesquiteunlike anythingfoundontheMoon. Volcanic&platetectonicfeatures Venus BasicInformaEon P=225days,almostcircular orbitwitharetrogradespin in243days R=6,100km d=0.7AU =5,250kg/m3 <T>~460C CO2atmosphere,90Emes denserthanEarthAtm. Lowerplains&Volcanoes withnosignsofplatetectonics Mars Ancientcrateredhighlands Deepvalleys&highVolcanos Lavafilledplains Earthlikeseasons JupiterlikeGaseousPlanets Outerplanetsaregenerallymoremassive,lessdenseandcold comparedtoEarthlikeplanets Summary 1.Exoplanets:DetecEonMethods(Concepts&DescripEon!) GravitaEonalLensing AstrometricMeasurement:angularseparaEon(smallangleequaEon) TransitMethod 2.SolarSystem Basiclayout:OortCloud,KuiperBelt,OuterSolarSystem,InnerSolarSystem Onedominantbody:Sun(CentralStar!) Twomaincategories:Earthlikerocky,Jupiterlike(orJovian)gaseousplanets Twosubmembers:Interplanetarydebris(Asteroids,Comets,Meteors) +Dwarfplanets WhythesesmallmembersofourSolarSystemareimportant? WhyPlutowasdethronedfromtheEtleofmajorplanets? FormaEonofSolarSystem:NebularTheory WhyNebularTheorysEllcan'tbeagreattheory?SelecEonEffect? Summary 2.SolarSystem EarthMoonSystem :6mainlayersofEarth :rockyinnercore+liquidoutercore >>How?(differenEaEon) :platetectonics :Impactcraters Terrestrial&GaseousPlanets :sharecommonfeaturesinacoupleofimportantaspectssuchas chemicalcomposiEons,densiEes. :Whatisthemostimportanttwomajorfactorsmakingsignificantdifferences betweenthemajorplanets? :WhoamI(descripEonsoneachplanet)? ...
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This note was uploaded on 02/15/2012 for the course AST 1002 taught by Professor Dr.haywoodsmith,jr during the Spring '07 term at University of Florida.

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