I've always wondered why gravity and acceleration are explained as two completely different concepts, yet they can be perceived to be the same exact thing under the right set of circumstances. Example: The room you are sitting in is mounted to the rear wall of the spaceship, so that you are sitting inside the craft perpendicular to its rear wall. The spaceship now accelerates forward at a constant rate that exactly matches that G-force of gravity on Earth. If you hadn't known your room was just transplanted to the accelerating spaceship, you would still think you were sitting in the room on Earth! Obviously the Earth is not accelerating in one direction, since "gravity" wouldn't then exist on the opposite side and we'd all fly off into space. But what if the entire universe was not only expanding, but it's nucleus was constantly accelerating in an ever-widening 3D spherical pattern. Perhaps mass simply warps the fabric of space such that the more mass, the more of this constant rate of acceleration that is exerted as "gravity." Do we know enough about the relationships between constant spherical acceleration, centripedal force, and even electromagnetism to discount such a theory?