What is time, and why does it seem to flow in only one direction? This video explores modern physics’ take on time—from the ...

The theory of special relativity is rife with counterintuitive and surprising effects, the most famous of which are length contraction and time dilation. If an object travels at a relative speed, ...

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.