At the risk of further muddying up the epicycling, let me offer a wild speculation concerning the expansion force. At the close of the infaltion epoch assumed by its advocates to have been at 10^-35 (superscript negative 35) seconds after time zero of the big bang, the universe is believed, again by big bang advocates, to have been no larger than the volume of a sphere of one light year radius and to consist of a very dense collection of photons and plasma. Ninety-five to ninety-seven per cent of this energetic soup is energy at the very high gamma energy level due to matter anti-matter particle annihilations to generate the current matter configuration of the universe. The expansion rate outward from this primordial one light year radius after 10^-35 seconds is much slower than light speed (probably ?) allowing this gamma level photon energy to supply an outward pressure on spacetime in opposition to the very intense (orders of magnitude larger than current) gravitational field. Also, due to the plasma state of the matter existing until the transparency state was achieved (release of what is now observed as the cosmic background radiation) and the likely equidistribution of kinetic energy across the electrons and protons, the electrons would have outraced the protons generating an inner sphere of mutually repelling protons surrounded by a spherical shell of mutually repelling electrons. (I'm not sure whether the lifespan of any neutrons that come and go during this phase allows them to be worthy of consideration, nor, if so, how to consider them.) Also the photons have outraced the electrons (most escaping prior to the forming of the proton sphere and the electron shell and their respective opacities). It seems reasonable to assume that most of the high energy matter-antimatter gammas (MAGs) have very quickly reached the space-time horizon since they travel faster than the post inflation rate of space-time expansion and faster than the electron shell. By this time they will be "pairforming" and annihilating at whatever rates the laws of physics allow (beyong my ability to speculate quantitatively) while bouncing back and forth between the horizon and the electron shell all within an unimaginably intense electric and magnetic field environment generated by the churning electron shell and the proton sphere. How could space-time avoid being stretched? And then momentum takes over. Any merit here?