# Model for viable time machine developed

A US scientist has developed a mathematical model for a viable time machine - an advance that could bring stuff of popular science-fiction closer to reality. Using math and physics, Ben Tippett, from University of British Columbia in Canada, has created a formula that describes a method for time travel. "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 Tippett. Ever since HG Wells published his book 'Time Machine' in 1885, people have been curious about time travel – and scientists have worked to solve or disprove the theory.

In 1915, German scientist Albert Einstein announced his theory of general relativity, stating that gravitational fields are caused by distortions in the fabric of space and time. More than 100 years later, the LIGO Scientific Collaboration - an international team of physics institutes and research groups - announced the detection of gravitational waves generated by colliding black holes billions of lightyears away, confirming Einstein's theory. The division of space into three dimensions, with time in a separate dimension by itself, is incorrect, said Tippett. 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. In the vicinity of a massive star, space-time geometry becomes curved and the straight trajectories of nearby planets will follow the curvature and bend around star. "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," said 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," he said.

While it is possible to describe this type of time travel using a mathematical equation, Tippett doubts that anyone will ever build a machine to make it work. "HG Wells popularised the term 'time machine' and he left people with the thought that an explorer would need a 'machine or special box' to actually accomplish time travel," Tippett said. "While is it mathematically feasible, it is not yet possible to build a space-time machine because we need materials - which we call exotic matter - to bend space-time in these impossible ways, but they have yet to be discovered," he said.

The research was published in the journal Classical and Quantum Gravity.