Find out how to keep time online accurately using World Clock, Time.now, Google Clock, and more. Learn how web-based time ...

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, ...

FOR THE discerning timekeeper, only an atomic clock will do. Whereas the best quartz timepieces will lose a millisecond every six weeks, an atomic clock might not lose a thousandth of one in a decade.

Physicists have demonstrated all the ingredients of a nuclear clock — a device that keeps time by measuring tiny energy shifts inside an atomic nucleus. Such clocks could lead to vast improvements in ...