One of the universe's most enduring mysteries is time travel. Discover why time travel into the future is unavoidable in the Einsteinian world of relativity. As for the past the laws of physics don't tell us it's impossible, but the bizarre consequences of going into the past and altering the future make for mind-bending science. Finally go for the future by traveling to the nearest star, 4.3 light years away in only 45 days.