freedomdwarf1
Posts: 6845
Joined: 10/23/2012 Status: offline
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FR~ According to Physics.nist.gov: The second is 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. And corroborated by techtarget.com: One second is the time that elapses during 9,192,631,770 (9.192631770 x 10 9 ) cycles of the radiation produced by the transition between two levels of the cesium 133 atom. Also, Wiki states: Since 1967, the International System of Measurements bases its unit of time, the second, on the properties of caesium atoms. SI defines the second as 9,192,631,770 cycles of the radiation that corresponds to the transition between two electron spin energy levels of the ground state of the 133Cs atom. That's good enough for me.
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“If liberty means anything at all, it means the right to tell people what they do not want to hear.” George Orwell, 1903-1950
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