When we discussed the formation of the moon via the "Giant Impact
Theory" we found that the model requires a collision between the early Earth
and a Mars-sized protoplanet. The collision splashed off the material from
the outer parts of the Earth which gathered together at a distance from the
Earth to make up our moon.
Now, having learned a bit about ring systems and tidal effects in the Jovian
planets, you can explore this model a bit further.
- How far away from the surface of the Earth did the material have to get
so that it could collect together under its own gravity?
Why could it have not formed any closer?
What do you think happened to the material that was inside this distance
after the initial collision?