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Prograde and Retrograde Rotation


In a prograde orbit, or prograde rotation, the planet spins in the same sense as its orbit of the sun. All planets except Venus and Uranus have prograde motion, and so the Earth spins from west to east which is the same sense as its orbit of the Sun. However, in the case of Venus and Uranus the spin is in the opposite sense which astronomers speculate is due to collisions early in the history with giant debris left over from the formation of the solar system.