What is the SI unit of time?

Official definition of a second

In 1967 a new SI definition of a second was created based on the radiation from the caesium-133 atom.

It is correctly defined as "the duration of 9,192,631,770 periods of the radiation corresponding to the transition between two hyperfine levels of the ground state of the caesium-133 atom."

Clocks and Time Tools

Our creative collection

Related Pages Portal to all articles Day and Night Map Converters by Region All Time Tools