It is theoretically possible to travel back and forth in time, according to physicists who claim to have created a mathematical model for a time machine.
Ben Tippett, from the University of British Columbia, and David Tsang, from the University of Maryland, have come up with a theoretical framework for travelling through time in a paper titled Traversable Acausal Retrograde Domains in Spacetime.
Yep that’s right, Whovians will tell you that’s what the Tardis in Doctor Who stands for.
“People think of time travel as something as fiction,” Tippett said. “And we tend to think it’s not possible because we don’t actually do it.
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“But, mathematically, it is possible.”
The physicists based their mathematical framework on Einstein’s theory of relativity.
Albert Einstein was a theoretical physicist who came up with the idea that gravitational fields are caused by distortions in the fabric of space and time. It is thought to be the reason why planets orbit elliptically around the stars.
His theory was confirmed more than a century later by LIGO Scientific Collaboration, a team of international physics institutes and research groups.
We see the universe in three spatial dimensions. Time – the fourth dimension – exists as a separate entity.
For their model, the physicists visualised all four dimensions existing simultaneously in the space-time continuum – where space and time are connected within the distorted fabric of the universe.
Tippett argues that time can also be bent like physical space.
“The time direction of the space-time surface also shows curvature,” he said. “There is evidence showing the closer to a black hole we get, time moves slower.
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“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.”
However, don’t expect to hop into a Tardis for a trip to the past because researchers are quick to point out a Doctor Who-style travelling machine won’t be built any time soon.
“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.”
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On paper, Tippett describes the machine as “a bubble of space-time geometry” which can move through space and time following a large circular path.
The researchers describe the device as a box allowing those inside it “to travel backwards and forwards through time and space, as interpreted by an external observer”.
Yep, we are still trying to get our heads around this one.
The research is published in Classical and Quantum Gravity.