Time travel possible: Hawking
According to the Daily Mail in Britain, Hawking said that spaceships may one day be so fast that time slows down for those on board. One day aboard a ship traveling at 98% of the speed of light – or 650 million miles per hour – would equal an entire year on Earth.
In the documentary, Hawking admits he was hesitant to discuss such theories previously, for fear of being labeled a “crank.” However, don’t blow your savings on a 1980s DeLorean just yet. Movies like Back to the Future hold no scientific weight, as Hawking explains people can only travel forward in time, not backward.
That’s because cause comes before effect, and traveling back in time would give people the ability to make themselves impossible by, for example, killing their parents – a paradox the laws of the universe would never allow, he said.