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second
(s)
subjectfact 
secondhas symbol s2001-09-27 09:32:53.0
has historical origin was defined originally as the fraction 1/86400 of the mean solar day2001-09-27 09:32:53.0
has definition A unit of time defined as the duration of 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium-133 atom. In 1967 the General Conference of Weights and Measures (CGPM) adopted this as the tentative definition of the second in SI units, replacing the ephemeris second, which remains in the IAU system of astronomical constants.has source: Hopkins, J. 1976 Glossary of Astronomy and Astrophysics, University of Chicago Press, 2001-09-27 09:32:53.0
has definition duration of 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom2001-09-27 09:32:53.0
is an instance of second unit2001-09-27 09:32:53.0
is an instance of base SI unit2001-09-27 09:32:53.0
time unitis a unit of time2001-09-27 09:32:52.0
SI unitis an acronym for Syteme Internationale2001-09-27 09:32:55.0
unitrepresents2001-09-27 09:32:42.0