Tracking time is one of those things that seems easy, until you really start to get into the details of what time actually is. We define a second as 9,192,631,770 oscillations of a cesium atom.

A photon emitted from a star a billion light-years away arrives at a telescope having experienced no time whatsoever. Not ...

Add Yahoo as a preferred source to see more of our stories on Google. GPS satellites must account for and correct for time dilation For centuries, humans have thought of time as a linear concept - but ...

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 ...

In 1916, only a year after Albert Einstein had published his general theory of relativity, Karl Schwarzschild used ...

Time runs faster on Mars (477 microseconds/day) due to relativity. Discover how this fundamental physics challenge requires dynamic correction to prevent massive GPS errors and secure future deep ...

Tiny “Ferris wheels” made from light and extremely cold particles could allow researchers to test a facet of Albert Einstein’s theory of relativity on unprecedentedly small scales. Theories of special ...

James is a published author with multiple pop-history and science books to his name. He specializes in history, space, strange science, and anything out of the ordinary.View full profile James is a ...

I am so intimidated right now...I think I understand less about relativity now than before I asked the question. I think - if I understand things as written - that time can be observed to slow for an ...