Poles of astronomical bodies pole. This definition means that an object's direction of rotation may be negative (retrograde rotation) — in other words, it rotates clockwise when viewed from above its north pole, rather than the "normal" counterclockwise direction exhibited by Earth's north pole. Venus rotates in the opposite direction to the other planets, and Uranus has been knocked on its side and rotates almost perpendicular to the rest of the Solar System. The ecliptic remains within 3° of the invariable plane over five million years, but is now inclined about 23.44° to Earth's celestial equator used for the coordinates of poles. This large
Retrograde and prograde motion Retrograde and prograde motion Retrograde motion in astronomy is, in general, orbital or rotational motion of an object in the direction opposite the rotation of its primary, that is the central object (right figure). It may also describe other motions such as precession or nutation of the object's rotational axis. Prograde or direct motion is motion in the same direction as the primary rotates. Rotation is determined by an inertial frame of reference, such as distant fixed stars. However, retrograde and prograde can also refer to an object other than the primary if so described. In our Solar System, the