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 dilation, a captivating concept embedded in Einstein’s theory of relativity, has been experimentally validated on Earth. With the use of ultra-precise clocks, scientists have been able to ...

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

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 ...