The time machine has always been a part of science fiction, but scientists from the University of British Columbia created a formula that describes a method for time travel. The study’s title, “Traversable acausal retrograde domains in spacetime,” creates the acronym TARDIS – the name of the famous police box time machine in “Doctor Who.”

“People think of time travel as something as fiction. And we tend to think it’s not possible because we don’t actually do it. But, mathematically, it is possible,” said one of the authors Benjamin Tippett.

#### The Unification Of The Four Dimensions

More than a hundred years ago, Alber Einstein announced its theory of general relativity, stating that gravitational fields are caused by distortions in the fabric of space and time. Two years ago, the LIGO Scientific Collaboration announced the detection of gravitational waves, confirming Einstein’s theory. The 102-year-old theory also states that the massive gravity of large objects forces spacetime to bend around them.

However, Tippett and his colleagues, have a different approach to the dimensions. They think it is incorrect to perceive the dimension of a time separated from the others. The four dimensions should be imagined simultaneously, where different directions are connected, as a space-time continuum.

Using Einstein’s theory, Tippett said that the curvature of space-time accounts for the curved orbits of the planets. In “flat” space-time, planets and stars would move in straight lines. The time direction of the space-time surface also shows curvature. There is evidence showing the closer to a black hole we get, time moves slower.

#### Creating The Bubble Of Space-Time Geometry

Tippett created a mathematical model of TARDIS described as a bubble of space-time geometry. This theoretical property carries its contents backward and forwards through space and time as it tours a large circular path. It would be able to move backward in time if develop speed greater than the speed of light, which is mathematically possible, according to Tippet.

Delighted external observers would be able to watch the time travelers within the box evolving backward in time: un-breaking eggs and separating cream from their coffee, the researchers explain in their paper.

Tippet reminds us that this is just a time machine described through a mathematical equation, but to be physically built it is currently impossible. The reason for that is the lack of matter, called exotic matter, which would have the ability to bend space-time in these impossible ways. We need first to discover such matter.

This model reminds on the Alcubierre drive, a hypothetical time machine, which is also based on Einstein’s equations and requires exotic matter to be built.