Ask Ethan: Can Gamma-Ray Jets Really Travel Faster Than The Speed Of Light?
“What gives? Is it really possible for gamma-rays to exceed the speed of light and thereby “reverse” time? Is the time reversal just a theoretical claim that allows these hypothetical super-light speed particles to conform with Relativity or is there empirical evidence of this phenomenon?”
Very recently, a paper came out claiming that gamma-ray bursts, and the jets that give them off, can travel faster than the speed of light. If that sounds too fantastic to be true, there’s a reason for that: particles can travel faster than light, but only in a medium, where the speed of light is less than the speed of light in a vacuum. Gamma-ray bursts, when they occur, exhibit a strange property: the signal is mostly a large peak, but when you subtract that peak out, parts of the residual signal are symmetric: if you flip it, part of it going forwards in time is identical to the remainder going backwards in time.