In Newton's theory the gravitational force at a given point and a given time depends on the positions of all masses at the same time, so a sudden change of any of the positions (such as a flare on the surface of the Sun) produces an instantaneous change in gravitational forces everywhere. This is was in conflict with the principles of Einstein's 1905 special theory of relativity that no influence can travel faster than light. This pointed to a clear need to seek modified theory of gravitation. In Einstein's general theory a sudden change in the position of a mass will produce a change in the gravitational field in the immediate neighborhood of the mass which then propagates at the speed of light to greater distances.