question

The reason is tied to the origins of the Solar System as a primordial Sun surrounded by initially randomly swirling clouds of dust and gas. Pulled towards the Sun by gravity, these clouds became denser, with internal collisions leading to a preferred direction of motion. Like water spiralling round a plughole, the collapsing clouds swirled in this direction at an ever-faster rate, eventually becoming dense enough to collapse under their own gravity and form spinning planets and moons. The one exception is Saturn’s moon Hyperion, which seems to have undergone a very violent impact, turning it into a potato-shaped rock that tumbles chaotically through space.