The concept of relativity of motion was first introduced by Galileo. In his principle of invariance he stated that the laws of motion are the same in all inertial frames. He used the Galileo’s ship thought experiment in his argument, among other arguments. This principle of invariance was then modified by Einstein (special relativity), which included the speed of light to be invariant in all inertial frames. Therefore, the relativity theory we know today is based on Galileo’s principle of invariance. There is no sound argument yet in support of relativity of motion. Simply because an observer hasn’t been able to identify between illusion of motion and real motion cannot be taken as a sound argument to support relativity of motion. In the usual arguments for relativity of motion, such as an observer closed inside a ship that is moving steadily on the sea , an observer flying in an aircraft steadily with windows closed, etc. to detect absolute motion is difficult. Detection of absolute motion requires a more fundamental approach, and not just looking through the windows. Absolute motion can be detected by observing change of the law of gravitation in our reference frame. Despite the advance of physics, the cause for the ‘elliptic’ shape of planetary orbits is unknown at a fundamental level todate. Newton’s law doesn’t predict the perihelion advance exactly and the discrepancy is said to have been corrected by Einstein’s general relativity and this is one of the evidences claimed to confirm Einstein’s general relativity. The finding in this paper shows that redefinition of Newton’s laws of motion and gravitation with respect to an absolute reference may solve the problem, without the need of Einstein’s general relativity. In this paper, a sound argument against Galileo’s principle of invariance will be presented, which will prove the notion of absolute motion to be correct and disprove relativity of motion, both Galileo’s and Einstein’s. Elliptic orbits are a result of absolute motion of the solar system in space, where as Mercury perihelion advance is a result of absolute centripetal acceleration of the solar system.