Gail Shaw wrote:
> "Orchid XP v7" <voi### [at] devnull> wrote in message
> news:4734b5ac$1@news.povray.org...
>> KalleK wrote:
>>
>>>> How the HECK did they measure that o_O
>>> It's defined that way: one meter is the 1/299 792 458 part of what light
>>> travels in one second in vacuum...
>>>
>>> (Well one meter was defined differently in former times...)
>> Sweet!
>>
>> So how do they define 1 second? (IIRC, isn't it the amount of time it
>> takes for the Sodium D-line to go through some defined number of
>> oscilations or something?)
> 
> Hyperfine transition of the Caesium-133 atom, iirc

...or Caesium, yes. :-}

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