Time travel has long lived in the realm of science fiction, but a growing body of physics research now argues that journeys into the past might fit inside known laws of nature without tearing ...

This month marks 40 years since Michael J. Fox, as Marty McFly, jumped into a souped-up DeLorean and went back in time, putting his very future existence at risk. (SOUNDBITE OF FILM, "BACK TO THE ...