Union Standard Second

The Union Standard time is officially based upon a multiple of the half life of a specific atomic weight of a specific element under a specific set of conditions. It's measured in Union Standard Seconds, Union Standard Minutes, Union Standard Hours, Union Standard Days, Union Standard Months and Union Standard Years.
 * Union Standard Secondis the standard unit of measurement in the Union Standard time.

The second is based on fundamental properties of nature. The second has been defined to be:

the duration of 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.

See also:
 * Planck time
 * Attosecond
 * Femtosecond
 * Picosecond
 * Nanosecond
 * Microsecond
 * Millisecond
 * Second
 * Kilosecond
 * Megasecond
 * Gigasecond
 * Terasecond