Kathrine Frich
Modern life depends on time being exact, invisible and constant.
From phone networks to navigation systems, even the smallest deviation can ripple far beyond the place where it begins.
Last week, a brief technical failure in the United States exposed just how fragile that precision can be.
Storm and shutdown
A powerful storm in Colorado disrupted power at the National Institute of Standards and Technology (NIST) campus in Boulder, temporarily knocking more than a dozen atomic clocks offline, according to US media reports cited by Xinhua and Agerpres.
Gizmodo reported that the failure occurred after a power outage overwhelmed backup systems at the facility.
In an internal email sent on December 19, physicist Jeffrey Sherman, a supervisor at NIST, said the atomic time scale at the Boulder campus went down on Wednesday.
The outage affected clocks responsible for maintaining the official time standard of the United States.
How time is kept
According to National Public Radio (NPR), the official US time, known as NIST UTC, has since 2007 been set by the Secretary of Commerce in coordination with the US Navy.
The standard is calculated using a weighted average from 16 atomic clocks based at the Boulder campus.
These clocks, including hydrogen masers and cesium beam clocks, measure time using the natural resonant frequencies of atoms, allowing for extreme precision.
The NIST time standard is used as a reference for systems such as telecommunications networks and GPS signals.
Gizmodo noted that while NIST has backup generators for grid failures, the storm also disabled one of the generators, leaving no secondary backup in place.
Microseconds matter
During the outage, some clocks lost connection to NIST’s measurement and distribution systems, resulting in a delay of 4.8 microseconds in NIST UTC, NIST spokeswoman Rebecca Jacobson confirmed.
To put that into perspective, Jacobson said it takes a human about 350,000 microseconds, or 0.35 seconds, to blink.
For most people, the delay would be completely imperceptible.
However, Sherman told NPR that the consequences depend on the application.
While everyday users would not notice the shift, systems tied to critical infrastructure, telecommunications and GPS could be more sensitive to such deviations.
Power was restored to the Boulder facility on Sunday, and assessment and repair work is ongoing, according to US media.
Sources: Gizmodo, NPR, Xinhua, Agerpres, Hotnews.
