ok, so the way the whole "gravity is a curvature of space-time" was explained to me was with a 2d model. If anyone has read flatland (not sure about the name) imagine that world put onto a sphere, which represents the universe. The radius of the sphere is time, and its expanding. Gravity would be like taking a ballon and pushing it in with your finger. From this view it seems a lot like momentum to me though. The sum of all momentum has to be 0, since the big bang was an explosion from a point. Therefore, and point in space-time with mass would have to go slower then points with less or no mass (p = mv). Does this sound possible? or do I have gravity wrong?