Time dilation and relative speed
July 13, 2004 4:53 AM Subscribe
Time dilation and relative speed. If the speed we travel is relative to the thing we're travelling away from, then how does the universe know which of the two things is actually moving? (so time dilation can occur) Is there a known universal "zero-speed"? If so, at what speed is the earth moving, and would it make a difference to the time dilation depending on the direction a spaceship moved away from the earth?