Experimental Strontium Atomic Clock Sets New Records, But Officially Can't Tell Time

An experimental strontium-based atomic clock is setting new time-keeping records and may further pave the way to replacing the current standard of cesium-based atomic clocks, which are used to calculate the official definition of time.

The National Institute of Standards and Technology (NIST) - the agency responsible for keeping the official time in the US - reports that a new strontium atomic clock has set new records for precision and stability, key metrics in measuring the performance of a clock.

The new clock is 50 percent more precise than the previous record-holder, the NIST reports in the journal Nature.

"Precision refers to how closely the clock approaches the true resonant frequency at which its reference atoms oscillate between two electronic energy levels," the NIST said in a statement. "The new strontium clock is so precise it would neither gain nor lose one second in about 5 billion years, if it could operate that long."

This is not the first time a cesium-alternative atomic clock has made headlines for record-breaking feats. In August 2013 the NIST reported a pair of Ytterbium atomic clocks set records for being the most stable time-keeping devices ever.

The new strontium clock matches the Ytterbium clock's record-breaking stability, which can be measured as the extent to which each tic of the clock matches the duration of every other tic. It is the first clock to hold world records for both precision and stability since cesium-fountain clocks were introduced in the 1990s.

Currently, the international definition of units of time is established by cesium-based clocks, such as NIST's F1 cesium fountain clock, which is used to keep standard time in the US.

By definition, only cesium clocks are considered accurate. Other experimental clocks operate at optical frequencies much higher than the microwave frequencies used in cesium clocks.

Given the advances in experimental atomic clocks, "the strontium lattice clock and other experimental clocks may someday be chosen as new timekeeping standards by the international community," the NIST said in a statement.