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 ...

Using Einstein's theory of general relativity, physicists found that clocks on the moon would run 56 microseconds faster than clocks on Earth. That finding will help future lunar missions navigate.

The big thinkers at Aperture explain relativity and how it warps the fabric of spacetime. House fails to override Trump's ...