The current international standard for timekeeping is based on an atomic clock using microwaves to flip the state of caesium atoms, an approach that provides 16-digit accuracy, supporting space ...

In the U.S., a new atomic clock called NIST-F4 has already proven to be one of the most precise timekeepers yet.

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 ...

If an atomic clock fell out of sync with a nuclear clock, for example, some change in the underlying physics might be responsible. Only time will tell. Curious about the world?