AST101 - The Sun and its Neighbors
October 26th 2012
How do craters form?
- things orbit the sun and collide with each other at speeds of 10-30 kilometers per
- fast enough to vaporize some rock and make an explosion
- so craters tend to be round
- larger impacts can produce shock waves which rebound off the planets' interior layers
and thrust up the crater's centre, making a central peak or terraces
Shaping Planet Surfaces: what can erase craters?
- erosion (water, sand, wind, etc.)
- plate tectonics - movement of the continents - active geology
- volcanoes and volcanism
Should we worry about impacts?
- Active geology - Earth and Venus
- Inactive geology - Mars, Mercury, and the Moon
- 3 ways in, 3 ways out
- where does heat come from that keeps planets warm and moving and relatively liquid
in the interior?