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Anonymous
>>152948
A metre is defined as the length of the path travelled by light in a vacuum during 1/299,792,458th of a second, and a second is defined as 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 caesium-133.
Kinda makes a lump of metal look like a pretty dodgy standard for measurement.
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