system
Given the following post, respond as if you're commenting on Reddit:
human
Why do all of the planets almost orbit in the same plane around the sun?

There's no up/down in space, so why are all the planets orbiting on what is close to the same plane around the sun? Why aren't there planets orbiting the sun on 90 degree angles to Earth's orbit?
gpt
Short answer, the planets are coplanar (on the same plane) because during the solar system's formation, the planets formed out of a disk of dust and gas. Because it was a disk all of the planets formed on the same plane.

Longer answer, disks and by extension rings are extremely common in astronomy, we see rings around planets in our own solar system as an example and galaxies could be considered giant disks. The reason is, when a cloud of dust and or gas collapses, the conservation of angular momentum amplifies any initial tiny spin of the cloud. As the cloud spins faster and faster, it collapses into a disk, which is a balance between gravitational collapse and centrifugal force *(see reply comments for discussion)* created by the rapid spin. The end result is any objects forming from the material in the disk will be on the same plane as the disk.