American time lagged behind the rest of the world by 4.8 microseconds. Here is what happened

A massive storm struck Colorado last week, disrupting more than a dozen atomic clocks and altering the US official time standard. Now the country is running 4.8 microseconds behind the world. These atomic clocks are located at the National Institute of Standards and Technology (NIST) in Boulder. Hurricane-force winds swept the state recently, hitting trees and electricity infrastructure. This posed a risk of fire, and so the state's largest energy company implemented safety shutdowns. But the atomic clocks continued ticking, thanks to the battery backup systems. However, a backup generator at NIST failed, causing a snap in operations and slowing down NIST coordinated universal time, or UTC (NIST), by 4.8 microseconds. Notably, NIST coordinated universal time, or UTC(NIST), determines the official time in the US. It is different from the other UTC used for the global time standard.

The minor time error can have huge implications

NIST supervisory research physicist Jeff Sherman described the time gap as "both big and small." He told Joe Hernandez at NPR, “All of the atomic clocks, a mix of hydrogen masers and caesium beam, continued ticking through the power outage last week, thanks to their battery backup systems. What failed was the connection between some of the clocks and NIST's measurement and distribution systems." This meant that the Boulder Internet Time Services no longer had an accurate time reference. A time difference of 4.8 microseconds might not seem much, but Sherman cautioned that it can affect crucial systems, such as infrastructure, telecommunications, GPS signals, and other things.

How is American time determined?

NIST has been America's official timekeeper since 2007. Of the 20 atomic clocks at the NIST laboratory that operate in rotation, 10 to 15 are working at any time to determine the US national time. Primary and alternate multi-channel measurement systems (MCMS) regularly monitor these clocks to quickly detect any changes in frequency. This data is fed into a computer algorithm, which, in addition to other machines, decides the exact US time. This figure works towards the world's time standards as well. Power has been restored at the facility, and assessments and repair work are being done.