To align Coordinated Universal Time with Earth’s rotation, a second occasionally gets added to the year. That may change in ...

For decades, the moon's subtle gravitational pull has posed a vexing challenge—atomic clocks on its surface would tick faster than those on Earth by about 56 microseconds per day. This extremely small ...

The difference between Japan Standard Time (JST) and Coordinated Universal Time (UTC) has been reduced from typically ±20 ns to less than ±5 ns by the inclusion of the optical lattice clock since ...

International timekeeping authorities are preparing to vote on a proposal to make the leap second—an extra second that is occasionally added to the year to keep Universal Coordinated Time in tune ...