Do all solar systems have their planets on the same plane?

I'm curious why this is. Are the orbits planer because of the gravitational pull the planets have on each other (I envision the creation of the solar system with eratic orbits all dampening to the center of mass). read more

The reason planets exist on the same plane has to do with how solar systems form. The collapse of a giant gas cloud, possibly begun by a push form a distant supernova, is what starts the whole process. The whole cloud begins to rotate around its ever collapsing center. read more

The orbits of the planets are coplanar because during the Solar System's formation, the planets formed out of a disk of dust which surrounded the Sun. Because that disk of dust was a disk, all in a plane, all of the planets formed in a plane as well. Rings and disks are common in astronomy. read more

Our Solar System is an orderly place, with the four inner planets, the asteroid belt, and the gas giant worlds all orbiting in the same plane around the Sun. Even as you go farther out, the Kuiper belt objects appear to line up with that same exact plane. read more