Is Time Travel really Possible? In this clip Professor Brian Cox – a confirmed Doctor Who fan – undertakes an experiment with a light showing that time moves faster for a stationary clock than a moving clock, which appears to move more slowly over the same length of time. His conclusion is that time travel is possible, but only into the future!
According to Einstein, time slows down the closer you get to the speed of light. Someone flying from London to New York, for example, will experience time passing a fraction slower than someone on the ground.
Prof Cox explained: “The central question is, can you build a time machine? The answer is yes, you can go into the future. You’ve got almost total freedom of movement in the future.
“If you go fast your clock runs slow relative to people who are still. As you approach the speed of light your clock runs so slow that you could come back 10,000 years in the future.”
Going back in time, or returning to the present, would be slightly trickier, however. Although the theory of General Relativity permits such a movement, it would require the Doctor to find a “wormhole” or shortcut in the fabric of space and time.
“Most physicists doubt it,” Prof Cox said. “Hawking came up with the ‘chronology protection conjecture’ – physics we don’t yet understand.”