The mind-bending concept of time dilation results from a seemingly harmless assumption—that the speed of light is the same ...

Einstein’s theory of relativity shows us that time isn’t constant,it stretches or contracts based on speed and gravity. But ...

Tuesday, July 22, is expected to be the second of three days in 2025 where more than a millisecond could be shaved off the ...

Scientists break down the reasons why days are getting shorter—and the mystery they're still trying to solve about Earth's ...

Some of these bikes have lower subscription fees, too -- or no subscription at all!