system
Given the following post, respond as if you're commenting on Reddit:
human
Why do the rings around a planet only form on one plane instead of forming multiple rings or a debris sphere?
gpt
Because they originally start that way but form into discs over time.

They do this because when two bits of debris collide in the initial debris sphere stages, 1 piece of debris will have more momentum and push the other bit of debris in that direction also.
This continues untill all the debris is moving in a uniform plane.