America's official time is kept at a government laboratory in Boulder, Colo., and according to the clock at the entrance, I was seven minutes behind schedule.

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 ...

An optical atomic clock measures the energy transitions of strontium atoms rather than the caesium atoms used in the clocks that are the world’s official time-keepers. Credit: K. Palubicki/NIST ...

The 1972 debut of the leap second meant that any time the two clocks grew apart by more than 0.9 seconds, we’d get a leap second—basically pausing the atomic clock to let the astronomical one ...

Like it or not, it’s time to fall back again. Most of the United States and Canada is about to switch to standard time, moving clocks back an hour Sunday morning. The official time change will ...

The UAE Official Time is regarded as an advanced model for time measurement. The caesium clock's frequency is based on the invariant properties of the caesium atom, making it a highly accurate ...

The United Arab Emirates Official Time is regarded as an advanced model for time measurement. The caesium clock’s frequency is based on the invariant properties of the caesium atom, making it a highly ...