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.

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 ...

Time dilation is a funny thing. We think of time as an immutable, shared reality, but you can technically observe time dilation simply by comparing the ticking of two atomic clocks, one at sea-level ...