A spacecraft traveling at 99 percent the speed of light toward Alpha Centauri would cross 4.3 light-years in what feels like ...

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 ...

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.