Something is throwing me here. No matter how fast one is going, relatively speaking, one is in the same universe as everyone (and everything) else. We're all going through the same spacetime, albeit at different velocities. You're in the same universe as I am and we both see the same space, light, and bikinis. If what I've already said is wrong, it makes me believe the universe itself is an idea that has no absolute form. Because, regardless of different speeds of motion, if we are "trapped" in the same universe and going through the same "spacetime", how can time dilation make any sense? For time dilation to make sense, it's almost like we're altering the universe by virtue of our speeds through it. WannabeNewton is in a spaceship (working on some huge equation that would take me 6,000 years to understand) and is going fast. The Great One (Peter Donis) is in a spaceship (flexing his muscles) going very fast. I'm in a spaceship (and throwing the ball for my golden) going very, very fast. However, we're all in the same universe and we're all going through the same spacetime. Unless our relative speeds are creating different universes (I'm sure I'm not saying this exactly right, but work with me), I don't see how the speeds matter. Is spacetime independent of the universe in which it's understood?