A power outage at the National Institute of Standards and Technology (NIST) laboratory in Boulder, Colorado, on Wednesday caused a 4.8-microsecond deviation in the U.S. official time standard, NIST UTC. The disruption resulted from a windstorm, followed by the failure of a backup generator. While the facility's atomic clocks maintained operation on battery power, connections to measurement and distribution systems were interrupted, leading to the drift.
Incident Details
The incident occurred on Wednesday at the National Institute of Standards and Technology (NIST) laboratory in Boulder, Colorado. An initial power loss caused by a windstorm was compounded by the subsequent failure of a backup generator at the facility.
NIST spokesperson Rebecca Jacobson confirmed that the U.S. official time standard, NIST UTC, became 4.8 microseconds slower than its intended value. This deviation is equivalent to approximately five millionths of a second. For context, an average human blink lasts about 350,000 microseconds.
Calculation of U.S. Official Time
Since 2007, the U.S. official time standard, NIST UTC, has been determined jointly by the Commerce Secretary and the U.S. Navy. NIST calculates this standard by averaging the readings from 16 atomic clocks located at its Boulder campus. These clocks, which include hydrogen masers and cesium beam clocks, utilize the precise natural resonant frequencies of atoms to maintain high accuracy in timekeeping. NIST UTC operates in conjunction with, but is distinct from, the global Coordinated Universal Time (UTC), to which the U.S. contributes measurements.
Cause of the Deviation
While the atomic clocks continued to function on their integrated battery backup systems during the outage, the connection between some of these clocks and NIST's measurement and distribution systems was interrupted. This interruption affected the system's ability to maintain precise timekeeping and accurately contribute to the national time standard.
Potential Implications
Jeff Sherman, a NIST supervisory research physicist, stated that the significance of the 4.8-microsecond drift is dependent on the user. The deviation is generally considered negligible for the general public. However, it could potentially affect specialized applications requiring high-precision time synchronization. These include critical infrastructure, telecommunications, and Global Positioning System (GPS) signals. NIST communicated the disruption to its high-end users, who have access to alternative time-keeping networks.
Response and Restoration Efforts
Critical operations staff on site were able to restore backup power by activating a reserve diesel generator. Power was fully restored to the NIST facility in Boulder by Saturday evening. Crews are currently engaged in evaluating the full extent of the damage and are working to correct the 4.8-microsecond time deviation.