Two familiar men in black suits are back in theaters on May 25, 2012, and this time, more than aliens are involved. In this released trailer for Men in Black 3, J discovers K has been dead for 40 years. With the help of a small device and a jump from the Empire State Building, J travels back in time to find some answers to K’s mysterious death.
Time travel is a popular storyline in television and film (Back to the Future, Lost, The Time Traveler’s Wife, to name a few). It is also a frequently requested subject for science consulting. But is it possible? Or even plausible? Well, we have some good news and we have some bad news.
The Bad News First
Time travel might not be possible. That is, if you wanted to time travel by violating the principle of causality, which states that “the cause must precede its effect,” you are (probably) out of luck. In July, scientists at the Hong Kong University of Science and Technology determined that single photons cannot travel faster than light. The speed of light is the “speed limit” of the universe, so going faster than it would violate the principle of causality allowing for time travel (the effect before the cause). “By showing that single photons cannot travel faster than the speed of light, our results bring a closure to the debate on the true speed of information carried by a single photon,” said Du Shengwang, assistant professor of physics at the university.
But There Is Good News!
Photons might not be able to travel faster than light, but that does not rule out time travel by wormholes! You do not need to travel faster than light to travel by wormhole. Technically, wormholes are theoretical, so your time traveling dreams might be dashed again. But, theoretically, because wormholes are connected on both ends, you could travel through one to end up in a different time period (or universe). Maybe the small device J carried in Men in Black 3 creates a wormhole for him to jump into, but the plausibility of that scenario is another article for another day. In the meanwhile, keep your time traveling hopes alive by dreaming of traveling through wormholes, and keep any eye out for how time travel is explained in the film in May!
Jenn Creighton is a science junkie with a writing backbone. She tweets about cool science at @gurlcode.