History of the Earth Chapter 1: Formation of the EarthFrom the Big Bang to Early PlanetsOrigins of…•The Universe (13.7 Gyr)• The Elements (13.7 - 4.6 Gyr)• The Solar System & the Earth (4.6 Gyr)• The Moon (4.5-4.6 Gyr)Origin of the Universe (13.7 Gyr)TheBig BangQuantum Mechanical Statistical Vacuum Fluctuation?History of the UniverseHubble Deep FieldOrigin Answer came from Distance vs.Relative Velocity of galaxiesDistance to GalaxiesDistanceActualBrightnessObservedBrightnessMeasured in:Light Years ~ 10 trillion km Parsec ~3.25 light yearsHow do we Know Distance?Velocity comes fromDoppler EffectElectromagnetic RadiationDoppler EffectDoppler Effect:Red Shift&Blue ShiftRed Shift of SpectrumslowfastnearfarGalaxiesHubble lawGalaxy VelocityMore Red ShiftedExpansion of the UniverseThe galaxies are not moving through space, they are stationary is space. Space itself, between the galaxies is stretching and carrying the galaxies farther away from each other.History of the UniverseWMAPWilkinson Microwave Anisotrophy Probe Microwave light emitted 380,000 yrs after the Big BangStars Begin to Form about 300,000 years after the Big BangAt that time Universe is:• 75% Hydrogen• 25% HeliumWhat about the rest of the elements?NebulaHow a Star WorksRadiationPressureGravityNucleosynthesisStellar Death: CollapseRadiationPressureGravitySupernova: Crab NebulaSupernova RemnantsOrigin of the Elements• Hydrogen & Helium: Big Bang• Helium to Iron: Stellar Fusion Multiples of 4 most common:Helium Carbon, Oxygen, Neon, Magnesium, Silicon, Sulfur, Iron• Iron to Uranium: SupernovaOrigin of the Solar System:The Data1. 99% of the mass of the solar system is in the sun2. We know thecomposition of the sun3. Planets orbit the sun in the plane of the sun’s equator4. Planets come in two groups:Terrestrial PlanetsMercury Venus EarthMars - Small, Dense and made of Rock and Iron4. Planets come in two groups:Jovian PlanetsJupiterSaturnUranusNeptune- Large, Low Density, and Made of Gas and IceAsteroidsMathilde & Eros (NEAR)Ida & DactylKuiper Belt & Pluto5. MeteoritesChondritesCarbonaceousOrdinaryChondrules under a scopeX-Ray ImageAbundance of Elements in Carbonaceous ChondritesAchondrite - Stony MeteroriteA stone from the Stannern eucrite showerthat fell over Moravia, Czech Republic in 1808.Iron MeteoriteStony-Iron:PalasiteOlivineIron6. Properties of the EarthOrigin of the Solar System:InterpretationSolar Nebula Hypothesis1. Start With a NebulaSomething (Supernova?) Triggers Nebula to CollapseEagle Nebula2. Nebula Collapses to form Protostar (Early Sun)Protostar Formation3. Residual Material Begins to Cool and Accrete3a. “Gas” Segregated by Melting Temperature and Condenses3b. Accretion: Dust Particles Accrete into Planetesimals3b. Planetesimals Accrete into PlanetsDaDa! - A Solar SystemDust Disks Around Young StarsExtrasolar PlanetsFirst Extra-Solar Planet Photographed (2005)4. Terrestrial Planets Heat up and Differentiate:Iron CatastropheHeat Comes From:1. Kinetic Energy of Accretion2. Gravitational Energy3. Radioactive Decay4. DifferentiationEarth’s InteriorMeteorite SourcesMeteorites & Solar System Age•Formation: 4.56 billion yearsMeteorites all with 20 myrs(earliest within few Myrs of supernova)•Supernova to sun and planetesimals - few million years! •Layered earth about 96±12 Myrs after meteorites•Nebula to layered earth & moon - about 100 MyrsEarth in the Early Hadean?2004 - Fred