The gold standard, if you will, for atomic clocks, is the element cesium, symbol Cs. Official civilian time is kept by the cesium NIST-F1 fountain clock, accurate to within one second every 100 ...

In Your Element Published: 24 March 2015 Quantum caesium Eric Ansoborlo & Richard Wayne Leggett Nature Chemistry 7, 360 (2015) Cite this article ...