The mechanism for the generation of gravity force has never been settled. Aether Physics explains it quite readily. I'm allowed to reinject the aether into physics, because the Michelson Morley experiment was flawed and erroneously ejected it. Gravity force next post, but first:

Then, several things come clear. Firstly, with the aether in place, the General Redshift of Starlight is attributable to simple Wave Dispersion. In which case, the universe is most likely in stable orbit about its own center of mass, exactly as our solar system and galaxy;- not expanding. And Wave Dispersion amplitude decay rate is nonlinear with distance;- as well as thermodynamic transfer lags of the waves from Aether-Line-Of-Force to ALOF, creating 2nd order curves. So the nonlinearity applies to redshift/distance relationship, and the universe is not accelerating in its "expansion" either.