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@ Jean-Francois Mezei
2025-03-03 23:06:32
nostr:nprofile1qy2hwumn8ghj7un9d3shjtnddaehgu3wwp6kyqpqc5laelfeypyl0xrlda7rjnq9frlajerezjm0jw0tvd3ch8t66t3qupwuyc What is a kilometre? Originally, was 1/10,000 the distance between equator and north pole.
But it has since been revised to:
"The effect of this definition is that one metre is the length of the path travelled by light in vacuum during a time interval with duration of 1/299 792 458 of a second."
The nautical mile used to be defined as a minute of arc around Earth. (variable distnce) Then minute of arc at equator and now as a direct conversion from 1852m.