A new atomic clock is one of the world’s best timekeepers, researchers say — and after years of development, the “fountain”-style clock is now in use helping keep official U.S. time. Known as NIST-F4, ...

Atomic clocks that excite the nucleus of thorium-229 embedded in a transparent crystal when hit by a laser beam could yield the most accurate measurements ever of time and gravity, and even rewrite ...

Every time you check the time on your phone, make an online transaction, or use a navigation app, you are depending on the ...