The past is the final frontier. Traveling back in time isn’t necessarily science fiction, according to a new paper published in Classical and Quantum Gravity. The paper’s title, “Traversable acausal retrograde domains in spacetime,” creates the acronym TARDIS – the name of the fictional time machine in “Doctor Who.” “People think of time travel as something as fiction,” Ben Tippett, the lead author of the study, told The University of British Columbia. “But, mathematically, it is possible.”

Specifically, the paper describes a spacetime “bubble” that would travel faster than the speed of light – thereby allowing it to move backwards. The idea that an object can travel through time if it reaches the speed of light is based on Albert Einstein’s theory of special relativity. But in order to traverse the past, we need something that doesn’t exist yet. And Tippet isn’t sure if it’s something that ever will. READ MORE