It’s a key plot element in television shows such as "Doctor Who" and the forthcoming "Terra Nova" from Fox, but a group of scientists says the premise just won’t work, according to the Los Angeles Times’ Technology blog. That premise is time travel.
Physicists at the Hong Kong University of Technology and Science have proved that time travel is beyond the limits of the universe’s physical laws, the story says. The idea that a photon could travel faster than the speed of light indicated the possibility of time travel, but a study published in the scientific journal Physical Review Letters by Shengwang Du and his colleagues concluded that a photon cannot move faster than the speed of light, the story says.
"By showing that single photons cannot travel faster than the speed of light, our results bring a closure to the debate on the true speed of information carried by a single photon," Du said in a statement issued by the Hong Kong University of Technology and Science.