Military Clocks Take Atomic Leap:

Ever since the US adopted the atomic clock as the time standard, the problem of the “leap second” has come up once every few years due to the discrepancy between an “atomic second” and an “astronomical second.” To make up for the lost time, the clock-watchers at the US Naval Observatory along with the 2nd Space Operations Squadron at Schriever AFB, Colo., had to add an extra second to their timepieces once the New Year came around this year. Both the USNO and the 2nd SOPS (who run the observatory’s backup clock at Schriever) have to ensure everyone in DOD gets the leap second accurate. The last leap second was on Dec. 31, 1998.