And 1 meter is the distance travelled by light in a vacuum in 1/299,792,458 of a second. It used to be 1/10,000,000 of the distance from the Equator to the North Pole along a great circle.
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And 1 kilogram in 'caesium photons' is c²/h·ν, where: h= 6.62607015×10^−34, ν= 9192631770, c= 299792458 in SI units. Giving exactly 3668388484640072×10^40/2486164202903619, or: 14755213997352709160650259536221241563890.5969… photons.
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It's beautiful how we can define simple things in complicated definitions.
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I would rebut that we simplify a complex reality for communicative purposes, as humans notoriously do.
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Any etymological connection between second as unit of time and second as following first?
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Yeah, originally there was a system of "first minutes", "second minutes" and "third minutes". First minute got shortened to "minute", second minute to "second", third was dropped entirely bc too short (1/60 of second) to be useful.
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And 1 kilogram in 'caesium photons' is c²/h·ν, where: h= 6.62607015×10^−34, ν= 9192631770, c= 299792458 in SI units. Giving exactly 3668388484640072×10^40/2486164202903619, or: 14755213997352709160650259536221241563890.5969… photons.
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You forgot one parameter: At 0 Kelvin. At other temp the duration of the transition is affected by the black-body shift.
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I’ll have my seconds call upon your seconds ...
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One day, could it be set according a pulsar ?
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Watches may grow significantly if we use that.
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A 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.
It was originally defined as the fraction 1/86,400 of a mean solar day.