This paper posits that the mechanism of gravity is the flow of spacetime. It also posits that spacetime is actually created in the vast voids between galaxy clusters. Spacetime flows into galaxies and bends the straight inertial paths of stars into curves, resulting in circular, elliptical, or parabolic orbits. It shows mathematically how the flat rotation curve of outer galactic stars results.Six quantum properties of spacetime are described: Spacetime is digital and consists of incredibly small particles. Spacetime is constantly being created in the vast voids of the universe. Spacetime is constantly being absorbed inside stars, planets, black holes, and by gases. Spacetime flows. Spacetime is incompressible at low speeds. Neutrinos and gravitons are emitted by stars.Six observable properties are described: The universe is expanding. The flow of spacetime will actually displace or move galaxies, stars, and planets. The flow of spacetime will bend starlight. The flow of spacetime is in constant flux. The flow of spacetime is without limit in distance. The effect of the flow of spacetime on the early clumping of matter after recombination.