Why do Saturns rings all lie in the same plane? Why are planetary rings always found in their equatorial planes and not sometimes crossing their poles?
Saturn, its rings, and most of its moons all probably formed from a spinning disk of gas and dust within the original solar nebula. As it collapsed toward its center, it would have formed a central sphere (which became Saturn), leaving a disk of material orbiting its equator. That material probably coalesced into many or most of Saturn’s moons. The ring particles may be material that was left over from this process, or they may be the remnants of a moon that was shattered by collision or by tidal forces (see Roche limit). In either case, the ring particles would have kept the angular momentum of the original disk, and continued orbiting Saturn in its equatorial plane. If Saturn captures particles coming in from other directions (along the polar plane, for example), they will tend to be pulled toward the equatorial plane, too. Saturn’s rapid rotation creates a centrifugal effect that produces a bulge around its equator. With more mass around its equator than at its poles, Saturn’s gravi
