Physicist presents theoretical model of travelling back in time

Time travel could be a real possibility in future, and not just a figment of imagination, according to an eminent Israeli professor of physics.

London, Aug 9 : Time travel could be a real possibility in future, and not just a figment of imagination, according to an eminent Israeli professor of physics.

Prof. Amos Ori from the Technion-Israel Institute of Technology has set out a theoretical model of a time machine based on Einstein's theory of general relativity, that shows how time can be warped by the gravitational pull of objects.

Under hypothetical conditions, the mathematical equations could lead to the formation of a time machine, technically known as "closed time-like curves", that would allow people to travel back in time to explore the past.

The equation states that in the blends of space and time, 'spacetime', time would be able to curve back on itself, so that a person travelling around the loop might be able to go further back in time with each lap.

Prof. Ori said that in the past, one of the major challenges has been the alleged need for an exotic material with strange properties - what physicists call negative density - to create these time loops.

"But, that is no longer an issue. You can construct a time machine without exotic matter," Prof. Ori told the Daily Telegraph.

It is now possible to use any material, even dust, so long as there is enough of it to bend spacetime into a loop, he said.

Even then, he has not given a hint as to when a time machine would be built, or even if it would ever be possible.

"There are still some open questions. The main remaining issue is the stability of spacetime, the very fabric of the cosmos, in time travel scenarios," he said.

"But overcoming this obstacle may require the next generation of theory under development, called quantum gravity, which attempts to blend general relativity with the ideas of the quantum theory, the mathematical ideas that rule the atomic world," he added.

But, Prof. Stephen Hawking, who in 1990 had proposed a "chronology protection conjecture", which said that the laws of physics disallowed time machines, has said there is experimental evidence that time travel doesn't exist.

"We have no reliable evidence of visitors from the future. (I'm discounting the conspiracy theory that UFOs are from the future and that the government knows and is covering it up. Its record of cover-ups is not that good)," said Prof. Hawking.

Prof. Ori's theory appears in the prestigious science journal Physical Review.

ANI