Rating is available when the video has been rented.
This feature is not available right now. Please try again later.
Published on Feb 23, 2012
Shows how we move through spacetime and that although different observers will disagree about distance, time and speed measurements, there are two quantities on which everyone can agree. Demonstrates that we move thro spacetime at the speed of light and that the more we move in space the less we move (and hence age) in time.