If gravity, gravitons, had a speed c_g less than the speed of light c, and gravity began with the big bang, then objects exceeding c_g at the time of the big bang could outrun gravity itself. It seems reasonable that c_g >= c. Even if in all cases c_g >= c, objects near the speed of c or even just distant from the center of the universe, i.e. the origin of the big bang, would have a diminished gravitational attraction to the center of mass of the universe because of retardation.
Retardation is the delay of effect due to transit time, in this case the transit time of gravitons. For distant objects, created at the time of the big bang, the gravitons from much of the universe are in transit, while for objects nearer the center of the universe a higher proportion of gravitons have completed their force transfer. Then net result is an apparent force accelerating objects that are further away from the center of the universe. This is not a true force, but rather an effect producing a force less than the expected gravitational force. The diminuation is proportional to the distance between bodies. This means a quantum treatment of gravity provides a possiblity other than either an ever expanding universe or an ultimately collapsing universe. That possibility is that matter sufficiently far away will not return to a big crunch, while other matter closer to the origin of the big bang may crunch. Gravimagnetics also provides a similar and at least partial explanation for dark matter. The gravimagnetic force, a 1/r^4 force, is powerful for objects close together. Ordinary orbital mechanics applied to close objects with similar spin axes will overestimate the mass involved, as compared to distant interactions of the same bodies. These are two sides of the same coin, depending on which mass information is obtained and relied upon first. The result is either apparent dark energy or dark matter, depending on the initial basis for determining the mass. Regards, Horace Heffner
