Do gravitational force is always attractive? Then what is the cause of expansion of universe?
One of the theoretical product ie INFLATON FEILD wen it is state to be in lower energy state after the inflationary epoch dis creats large repulsive force thus it accelerates more dan the speed of light, in the beginning of the infant of big bang and gradually the rate decreases thus dis is cause for the expansion of universe.
The new theory called 'INFLATIONARY EPOCH ' which is put on a frim for the cosmological inflation and this is evidently proved ,the BICEP2 detected inflationary gravitational waves in the B-mode power spectrum.this theory explains the current characteristics of that galaxy.
The existence of dark energy is not proved and anti_gravity doesn't exist ( although Einstein s unity theory talks about it the theory is incomplete)
Anti gravity could replace Dark energy for xpansion of universe.