On Gravitational Repulsion

The concepts of negative gravitational mass and gravitational repulsion are alien to general relativity. Still, we show here that small negative fluctuations small dimples in the primordial density field that act as if they have an effective negative gravitational mass, play a dominant role in shaping our Universe. These initially tiny perturbations repel matter surrounding them, expand and grow to become voids in the galaxy distribution. These voids regions with a diameter of 40h Mpc which are almost devoid of galaxies are the largest object in the Universe. 1. Strange and Not So Strange Negative Masses Two (gravitational) negative masses attract each other. The equivalence principle requires that their inertial masses is negative as well. In this case the masses move away from each other. A negative and positive mass pair is even stranger. They repel each other. The positive mass moves away from the negative one but the negative mass accelerates towards the positive one. The distance between the masses does not vary while they are jettisoned together at a constant acceleration. Momentum and energy are conserved as