Given a law of gravity and an assumption about how the matter is distributed, the next step is to work out the dynamics of the universe - how space and the matter in it evolves with time.

A spinning black hole would have imparted some spin to the space-time inside it, which would violate a law of symmetry that links space and time.

The equation of the law of universal gravitation is deduced on the basis of einstein's relativity with newton's viewpoint of absolute space time.