Assume 2 massive bodies are moving away from each other at high speed. Since the gravitons which cannot travel at faster than the speed of light, are having a hard time being exchanged by these two bodies, it must be plausible to assume that the gravitational pull between these two bodies would be diminished. Relativity mechanics should be able to calculate the new gravitational forces between the 2 moving bodies, which will reduce to zero gravitational forces when the relative velocity of both bodies reaches a certain value. Assuming that for a graviton to be exchanged between 2 massive bodies, that graviton has to make a round trip, ie. forward and back, and assuming that gravitons travel at the speed of light, this will lead us to deduce that the effective velocity of gravitons are half of the speed of light. (c/2). This leads me to the prediction that at speeds close to c/2, the gravitational pull between 2 bodies would reduce to zero newtons. Now in the case where both bodies are moving away from each other faster than half the speed of light, this might result in repulsive gravitational forces. The accelerating, expanding universe observations is an indisputable and repeatable experimental proof of repulsive gravity and which may be modeled based on my hypothesis above. Any comments?