Gravity doughnut may solve time travel problem

[Ivan Seeking]

"Gravity doughnut" may solve time travel problem

One of the major difficulties of traveling backwards in time has just been solved, according to an Israeli theoretical physicist. And the solution, he says, is doughnut-shaped...

...This is where Amos Ori from Technion, the Israel Institute of Technology in Haifa, comes in. He says that according to Einstein's theories, space can be twisted enough to create a local gravity field that looks like a doughnut of some arbitrary size. The gravitational field lines circle around the outside of this doughnut, so that space and time are both tightly curved back on themselves. Crucially, this does away with the need for any hypothetical exotic matter. [continued]

http://www.nature.com/news/2005/050711/full/050711-4.html

 

[George Jones]

The arXiv version is here.

Regards,
George

 

[Chronos]

Ori is captivated by the concept of self-interacting gravitational fields, which I do not find very interesting. It's the sort of unobserved 'ultraviolet catastrophe' that signals an incomplete theory.

 

[pervect]

This is still interesting, because according to the author it does get around Hawking's chronology protection result (Phys. Rev. D46 (1992) 603).