How a power outage in Colorado caused U.S. official time be 4.8 microseconds off

Cesium beam clocks (left) and hydrogen masers are among the types of atomic clocks used by the National Institute of Standards and Technology (NIST) to determine official U.S. time.

Officials said the error is likely be too minute for the general public to clock it, but it could affect applications such as critical infrastructure, telecommunications and GPS signals.

(Image credit: J. Sherman, R. Jacobson)