History of the Earth Chapter 1: Formation of the Earth From the Big Bang to Early Planets

Origin of the Solar System: The Data

1. 99% of the mass of the solar system is in the sun

2. We know the composition of the sun

3. Planets orbit the sun in the plane of the sun’s equator

4. Planets come in two groups: Terrestrial Planets MercuryVenusEarth 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: Interpretation Solar Nebula Hypothesis

1. Start With a Nebula Something (Supernova?) Triggers Nebula to Collapse

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? Fred Sulahria