Power Disruption at NIST Affects U.S. Official Time
Boulder, Colorado – A power outage at the National Institute of Standards and Technology (NIST) laboratory in Boulder, Colorado, resulted in a 4.8-microsecond deviation in U.S. official time (NIST UTC). The incident occurred on Wednesday following a windstorm that caused an initial power loss, compounded by the subsequent failure of a backup generator.
Calculation of U.S. Official Time
The U.S. government determines the country's official time using a network of atomic clocks located at the NIST facility. Since 2007, the Commerce Secretary, in conjunction with the U.S. Navy, has overseen the national time standard, known as NIST UTC. This standard is distinct from the global Coordinated Universal Time (UTC), to which the U.S. contributes measurements.
NIST currently calculates the standard by averaging the readings from 16 atomic clocks on its Boulder campus. These clocks, which include hydrogen masers and cesium beam clocks, utilize the precise resonant frequencies of atoms to maintain high accuracy in timekeeping.
Cause of the Deviation
While the atomic clocks continued operation due to their integrated battery backup systems, the power outage disrupted the connection between some of these clocks and NIST's measurement and distribution infrastructure. Critical operations staff on site were able to restore backup power by activating a diesel generator held in reserve.
Potential Impact
The 4.8-microsecond drift, equivalent to approximately 5 millionths of a second, is considered negligible for the general public. For context, an average human blink lasts about 350,000 microseconds. However, the deviation could have implications for specialized applications requiring extreme precision, such as critical infrastructure, telecommunications, and Global Positioning System (GPS) signals. NIST has confirmed that "high-end" users of its time-keeping networks were informed of the disruption.
Restoration Efforts
Power to the NIST facility was restored by Saturday evening. Crews are engaged in evaluating the full extent of the damage and are working to correct the 4.8-microsecond drift.