Tom Weiler of Vanderbilt University says, "Our theory is a long shot, but it doesn't violate any laws of physics or experimental constraints." What theory is this? That when the LHC produces the long-sought Higgs boson, it will also produce a companion particle, the Higgs singlet. Weiler will watch for evidence that Higgs singlets and their decay products appear at the same time, which would mean the decay products are produced by singlets which "travel back in time to appear before the collisions that produced them." M theory, the current version of string theory, says that Higgs singlets should be affected by gravity but not by any other force - meaning they could move in time.
COMMENT: OK, it's not Admiral Kirk going back to the 20th century to save the whales. But the point is this may show time is not a relentless one-way arrow. It may have exceptions. And who knows where that insight may lead in the future?