Which atomic clocks are best? The first time zone, Greenwich Mean Time, was established in the late 1600s to assist sailors before the invention of the train and railway in the mid-1800s expanded the ...

Every single day, humans rely on hundreds of hidden clocks. GPS location, Internet stability, stock trading, power grid management ... all rely on atomic clocks in order to work. Many of those clocks ...

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, ...

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 ...