Either I've never asked this before or it has never come up (for me anyway). Ok, when you see a diagram of the solar system you see all the planets (and now dwarf planets) orbiting the sun in their nice elliptical orbits. Now these orbits are represented as being on the same "plane" as if they are all floating on the top of a pool. Now I have seen some that show the orbits to not be at the same "height" in space, some a little higher and some a little lower, but about the same for the most part. Now to my question. Have/do astronomers look for planets in our solar system that do/might not orbit along this plane? The reason I ask is because all the outer objects we've found in the kuiper belt seem to also be on this plane. Also, I am aware that some comets and asteroids orbit at various angles to the sun than the main body of planets. So why wouldn't/couldn't a planet? Hope my question makes sense. Thanks.