Since childhood we have learnt that all the planets go around the Sun. Meaning, the planets and other celestial objects rotate around the Sun in specific directions. But did you know that not all follow the same directions? Some follow the Sun’s rotation while some go in the opposite direction. After observing these motions of certain planets and comets, astronomers termed these rotations as “ Prograde ” and “ Retrograde ”. Before we get into these terms, let’s first understand how the direction of the motion is determined. The direction is determined by the primary object in system that forms the system’s hub. In our case, it is the Sun. So rotation of all the planets and celestial bodies is decided by the Sun’s direction of rotation. Now that we know how the motion is determined, let’s get into the above mentioned terms. Prograde: It is the motion in the direction of that of the Sun. Meaning, most of the planets and some comets move in the direction of the ...