Question: does the physical curvature of spacetime ever "move"? Something isn't adding up with Einstein's theory--or, more likely, I'm just not understanding it correctly! How can we say that the curvatures of spacetime created by the presence of stress-energy is giving us a continuum? When I think of a continuum, I think of something like a tunnel. But it cannot be so! If all motion is relative, how can we have this tunnel? Yeah, sure we live and die, so we like to think of the world in time-like ways, but if I'm reading Einstein's theory right, I don't see how we can look at spacetime curvature as anything more than a localized dent in space (that cannot be regarded as being bent in any kind of continued way, like a tunnel). I'm really hoping the GREAT Peter Donis gets a hold of this question, because I know I'm not asking it perfectly but that he can probably figure out what I'm asking. Edit: Wait a minute. Have I answered my own question? Is the passage of time the tunnel I'm trying to visualize? Ha! I think I figured it out! The tunnel--or the continuum--is time, right?