Our solar system mostly revolves around the sun on the same axis (apart from Pluto). Our galaxy does the same (along with other galaxies). Why? Gravity is linear?
Would it matter if we tried to escape the sun’s gravity by going “up?”
Because everything is in the process of falling the same direction. It’s like if you throw a bucket of water and ask why none of the droplets went sideways.
It’s a common shape in the universe: large spherical mass in the center, plane of objects rotating around it.
Imagine a new object orbiting Saturn in a random direction. At some point (two, actually), it will cross the plane of the rings. Eventually it will crash into an object. The average of the impact will be closer to the plane. Eventually, it will either align with the plane or its orbit will be unstable.
Doesn’t even have to impact. The gravity of other bodies in orbit will pull out-of-plane objects closer to the plane over time.
Best video you’ll ever see on the topic imo (and very short)
I asked this question many years ago on a Usenet group, and the answer was along the lines of what we’re seeing is many millions of years after those orbits began, and that they all eventually flatten out due to the gravity of the other objects in orbit.
So you could have 2 objects at roughly the same orbital distance but perpendicular to one another (eg. one orbiting the star’s poles and the other around it’s equator), and over time the small amount of gravitational force they exert on one another will bring them roughly into the same plane.
Hopefully someone better versed in the topic can come along to explain it better than I can.
Any two objects will orbit each other in a plane. The interesting things start to happen after a third body is introduced.
I feel that might become a… problem.
