URANUS
1 none. [Astronomy] One of the giant planets, the seventh planet from the sun, is sometimes visible to the naked eye. It has 27 satellites, a ring system, and an axis of rotation almost lying in the plane of the orbit. Mean distance from sun: 2870 million km; period of revolution around sun: 84 years; period of axial rotation: 17.23 hours; diameter and mass: 4 and 14.5 times that of earth respectively.