The Formation of the Solar System The Nebular Hypothesis

The Solar System formed ~ 4.6 billion years ago –Evidence from: meteorites ( billion years old) moon rocks (~4.0 billion years old) Earth Rocks(~3.9 billion years old) –sedimentary minerals ~ 4.2 by

The Beginning All stars, including our sun come from nebula Nebula are the remains of old stars that have exploded Nebula contain all of the natural elements Eggs in nebula are where stars are born

The Big Spin An external force causes the “egg” to spin counterclockwise Gravity –pulls the cloud inward creating a flattened disc The Conservation of Angular Momentum –As the disc begins to flatten it begins to spin faster –Think of a ice skater

The Disc 90% of the material was in the center 10% of the material was in the disc surrounding it SUN Planets, comets, Asteroids, Moons

The Formation of the Sun Within the center of the disc: –Compression and Friction –Temperature Increase –Sun “turned on” Hydrogen fusion began

The Formation of the Planets Accretion: –particles in the disc condensed forming ice and rock –these particles continued to collide and combine into large planetesimals Continuing to spin, compress and collide the planets and moons formed

Solar Winds blew excess gas toward the outer planets leaving the inner planets rocky

Nebular Hypothesis Visualization CLICK HERE

What makes this a good hypothesis? All of the planets travel in the same direction (counterclockwise) All of the planets are in the same plane Angular Momentum is clearly understood Nebula are very real and very common