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.

What does the passage of time look like for a truly quantum object? The world’s best clocks may soon be able to answer this question, testing how time can stretch and shift in the quantum realm and ...

Modern science reveals time's variable flow. Einstein's relativity explains how speed and gravity alter time's pace. This ...