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 ...

Time travel is one of the hallmarks of science fiction, but many time-travel-based movies have plots that leave one with a headache just thinking about them. What if you could travel into the past, ...

Time travel has shifted from pure fantasy to a serious, if highly constrained, topic in modern physics. The equations that describe gravity, quantum fields and the structure of spacetime now allow ...