What Creates Gravity?

I am unsure what you mean by "space is rushing away" but if you are in reference to the fact that the universe is accelerating, as opposed to collapsing in as would be thought because of the "big bang". but the universe is actualy accelerating in its expansion. This is evident when you start looking at galaxies and star systems that are further from earth. the further something is from earth, the faster it is accelerating away from us, and subsequently from the "epicentre" of the big bang. The acceleration is easily seen when comparing two galaxies that are somewhat near to each other in the night sky, and viewing both, the one that is further away will be experiencing more red-shift from the Doppler effect. and therefore is moving fastter away from us, and each more distant object we find is more and more red shifted.