Albert Einstein discovered that time is relative, meaning that when objects travel at, or close to the speed of light, distances stretch and time slows down. Learn more about light, time, mass, energy and the very fundamentals of the universe in these videos.
NOW PLAYING (0)of
Can time travel allow us to visit the future? Watch as a child explains Einstein's theory on the elasticity of time on The Science Channel's "10 Ways to See into the Future."