Retrograde and prograde motion orbits about the Sun of all planets and most other objects, except many comets, are prograde, i.e. in the same direction as the Sun rotates. The rotations of most planets, except Venus and Uranus, are also prograde. Most natural satellites have prograde orbits about their planets. Prograde satellites of Uranus orbit in the direction Uranus rotates, which is retrograde to the Sun. Retrograde satellites are generally small and distant from their planets, except Neptune's satellite Triton, which is large and close. All retrograde satellites are thought to have formed separately before being captured by their planets. When a galaxy or
Retrograde and prograde motion the side of the Earth facing away from the Sun (i.e. at night) whereas the prograde meteoroids have slower closing speeds and more often land as meteorites and tend to hit the sun-facing side of the Earth. Most meteoroids are prograde. The Sun's motion about the centre of mass of the Solar System is complicated by perturbations from the planets. Every few hundred years this motion switches between prograde and retrograde. Stars and planetary systems tend to be born in star clusters rather than forming in isolation. Protoplanetary disks can collide with or steal material from molecular clouds within the