Ytterbium is a bit lighter than previously thought: Its standard atomic weight is now 173.045, down from 173.054, as approved by the International Union of Pure & Applied Chemistry (IUPAC) in August.

The story of scientific advancement is rarely one of leaps and bounds. More often than not it's evolution over revolution, and the story of the so-called ytterbium atomic clock fits that bill ...

Are the fundamental constants really constant? Recent investigations have shown that one essential fundamental constant -- namely the mass ratio of protons to electrons -- can have changed only by a ...

National Institute of Standards and Technology (NIST) physicists have set a new world record for atomic clock stability using a pair of ytterbium-based timepieces. Stable down to quintillionths of a ...

Time might feel like something we've got a pretty good handle on, but scientists are trying to find new ways to measure it ever more accurately. In recent tests run by the National Institute of ...

This is an atomic clock that uses the predictable frequency of ytterbium atoms absorbing and emitting light to tell time. A new experiment paired a ytterbium-based atomic clock with two others that ...