There isn't any gravity. There is only inertia. The reason it feels like gravity is the expanding universe. The material of the earth is expanding right under us. It is pushing us outward, away from the earth's center.

Not only is there expansion of the material in the universe, but its expansion is increasing in rate of expansion. That's why we feel gravity. It's this rate of expansion increase that we feel, as inertia tends to keep us remaining at a constant expansion velocity. The only reason we can measure it is that there are some energies that expand a slightly different rates than the materials do.