I was looking at this link: http://en.wikipedia.org/wiki/File:Universe_Reference_Map_%28Location%29_001.jpeg" [Broken] and wondered to myself why the asteroid belt just outside of Mars is a ring...as opposed to a sphere. Then I thought, why do all the planets seem to orbit the sun on a similar plane. For example, earth and mars have similar orbit planes. Why wouldn't one have a plane of orbit 90 degrees crossed of another? I couldn't find a good answer online...it's probably simple! :p Note: I say "sphere" but obviously it can only orbit in a ring. Just imagine, however, that each orbit path left a tracer line behind it. Their orbits wouldnt create spheres over a long timespan would they? Hope that makes sense!