sekuntia

Sekuntia is a unit of time in the International System of Units (SI). It is defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom. This definition was adopted in 1967 and re-confirmed at the 1983 General Conference on Weights and Measures. The symbol for second is 's'.

The second is the base unit of time in the SI system and is also used in many other systems of measurement. It is one of the seven base units of the SI, alongside the meter, kilogram, ampere, kelvin, mole, and candela. The second is fundamental to many scientific and engineering calculations, as well as everyday timekeeping. Before the cesium atomic clock definition, the second was defined based on astronomical observations, specifically the duration of a tropical year. The transition to an atomic definition provided a much more precise and stable standard.