Time travel is definitely possible, but you'd only be able to go one direction: Forward.
During his presentation at the British Science Festival, particle physicist Brian Cox claimed that time travel is indeed within the realm of possibility, but there are a few caveats.
"The central question is, can you build a time machine? The answer is yes, you can go into the future," he said. "You've got almost total freedom of movement in the future."
Under Albert Einstein's theory of relativity, an individual could travel hundreds, even thousands of years into the future if they were moving fast enough. How fast? Speed of light fast.
"Imagine twins, one stays on Earth (Twin A) while the other (Twin B) boards a spaceship and flies off at relativistic speeds. Compared with Twin A's timeframe, Twin B's timeframe will slow. If time is running slower for Twin B, then he/she will return to Earth where a lot more time has passed and Twin A has aged significantly more than Twin B. The mechanism behind this is 'time dilation' and it has a stronger effect as you travel closer and closer to the speed of light."
The only problem is that once you get to the future, you're stuck there. Additionally, traveling backwards is almost completely out of the question.
Citing the popular cult show Doctor Who, Cox said that traveling to the past would only be possible via a wormhole. Problematically, this theoretical shortcut through space-time, also proposed under Einstein's general-relativity theory, has never been proven to exist, and we have no idea whether we'd even be able to use it to travel back in time anyway.
Would you take a chance and time travel to the future?