Where did the length of a meter come from?

Answer 1

The meter was defined in 1790 as one ten-millionth (10 to the -7th power) of the Earth's quadrant passing through Paris. It was redifined - because the earth is not a sphere, after all, but an oblate spheroid - in 1960, as equal to 1,650,763.73 times the wavelength in a vacuum of the orange-red radiation of krypton 86. In other words, the meter is a length totally unrelated to anything in human experience, which supports the assertion that only a machine could love the Metric System.