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3 months agoDude, WTF are you talking about? When I was a machinist it was so much easier to deal with metric. 1 inch ~ 25 mm, from there it is just way easier to deal with measurements such as 27.5 mm instead of 1 5/64 inches and all of these inverse powers of 2. I was always jealous of the French machinist I worked with talking about how the only units you should ever have to work with is meters and millimeters. If you are concerned about “Human Scale” then intuitively a meter and a yard are close enough for estimates and you don’t have to deal with “wait, what is 5/8 + 3/16 + 1 7/64?”
A real geologist should give a real answer, but more or less it is due to how the molten elements and molecules sorted out back when the earth was younger and hotter. It has a lot to do with relative densities, melting points and propensity to mix with other materials. Everything heavier than helium and trace amounts of lithium are “star dust”, the geology of earth is how that coalesces together and then combines and separates out in geological processes.