the Solar Nebula
- Eventually the centrifugal force overcomes gravity and stops the contraction in the radial direction
- Left with a disk of rotating material -- the Solar Nebula
- same reason the Milky Way is a rotating disk
- Fig. 16-6, view of Milky Way in infrared
- Lowest angular momentum material gathers in the center to form the Sun
- Planets form out of the remaining solar nebula
- This formation scenario explains the major features of our Solar System
- All the planets orbit near to the ecliptic
- This is the presumed plane of the Solar Nebula disk
- All the planets orbit in a counter-clockwise direction
- This reflects the rotation of the Solar Nebula (original spin)
- Most planets have their rotation axis close to the ecliptic axis