No seriously. Well, progress sort of. Theoretical progress, at any rate, and still hinging on one monster of a caveat: that spacetime is curved appropriately.
A group of researchers led by Amos Ori at the Technion in Israel has developed a theoretical model that overcomes a major hurdle in the current time travel theory. First of all, time travel requires the existence of closed timelike curves (CTC, aka closed timelike loops). In relativity theory, every particle has a worldline that describes its position in space and time throughout its existence. If the particle is in orbit around a mass of very high density that is greatly curving spacetime, it is possible that the worldline of this particle curves back on itself not only in space, but in time. The major hurdle in current theory is that for a time machine to exist, it would have to have negative density (another interesting topic, but I’ll have to save it for some other time). So according to Ori’s new theory, all that is needed is for gravity to have already begun curving spacetime appropriately and then for us to create “a vacuum space that contains a region field with standard positive density material.”
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