Mathematicians try to create a real Tardis, melt our brains in the process

What did they call it? A Traversable Acausal Retrograde Domain in Space-time. TARDIS for short.

Sure, we might not be talking about an actual blue police box containing a two-hearted alien and his human companion who have to hurtle through space and time fixing all the problems in the universe. But we are definitely talking about an actual "time machine".

You might have to get a few degrees in physics and mathematics to really understand the details, but Tippett tells Science Daily that it is possible.

"People think of time travel as something as fiction," he says. "And we tend to think it's not possible because we don't actually do it. But, mathematically, it is possible."

Their theory attempts to present the geometry of a "time machine" - that is, a box allowing those inside it "to travel backwards and forwards through time and space, as interpreted by an external observer."

Taking Einstein's theory of general relativity as a starting point, the scientists argue that the curvature of space-time theoretically allows for passengers to travel in a time 'circle', rather than a straight line from past to future.

"There is evidence showing the closer to a black hole we get, time moves slower," says Tippett. "My model of a time machine uses the curved space-time – to bend time into a circle for the passengers, not in a straight line. That circle takes us back in time."

This is not the first time the scientific duo, who study black holes and Einstein's theory of relativity when they're not trying to make a Tardis, have tackled the maths of time travel. They released a paper back in 2013 where they first proposed the long-imagined time machine.

But there is still plenty of work to do on the thorny problem, so don't expect to hop into a Tardis for a trip to the future quite yet. "Spacetime geometry is geodesically incomplete, contains naked singularities, and requires exotic matter," the two scientists conclude.

Yeah. What they said.