> guilty as charged. it gets worse, though: meters are originally based on the size of the earth, but humboldt's expedition (?) fucked up the measurement and now we're stuck with a meter that's significantly too short
Uhm, a kilometer is supposed to be 1/40000-th of the Earth's meridional (i.e. from South to North poles) circumference. The modern value is 40008km, so the official meter is juuuust about 0.02% shorter than it should be.
i think it was a ten thousandth of the distance from the north pole to the equator through paris, disregarding the southern hemisphere, which was more difficult to survey. i've been looking for a precise number for how far that distance actually turned out to be, but i haven't been able to find it; i would be delighted if you could!
whether 0.02% sounds ridiculously good or ridiculously bad depends on your frame of reference
https://en.wikipedia.org/wiki/History_of_the_metre#History_o... says that the original mètre des archives in 01799 was machined to within 50μm, which is 0.005%, four times smaller than the error in delambre and méchain's computation. so even at the time that was a pretty large error. since then the measurement uncertainty of the meter has improved by five more orders of magnitude, to about 0.1 part per billion. 0.02% is 200 parts per million, or 200000 parts per billion, which is a lot more than 0.1
Uhm, a kilometer is supposed to be 1/40000-th of the Earth's meridional (i.e. from South to North poles) circumference. The modern value is 40008km, so the official meter is juuuust about 0.02% shorter than it should be.