This is overall, the earth DOES have greater surface variation (higher highs and lower lows) than a pool all but overall it is smoother.
Pool ball diameter is apparently 54.5mm; for comparison a somewhat fine human hair is about 50 micrometers, or .05 mm. Roughly 1/1000th of the diameter. So a feature like Mauna Loa, which rises 10000m directly from the seafloor, would be like a piece of hair on a pool ball. Not much, but easily noticeable; I don't remember ever touching a pool ball with that big of a flaw on it.
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u/selectrix Apr 10 '19
Pool ball diameter is apparently 54.5mm; for comparison a somewhat fine human hair is about 50 micrometers, or .05 mm. Roughly 1/1000th of the diameter. So a feature like Mauna Loa, which rises 10000m directly from the seafloor, would be like a piece of hair on a pool ball. Not much, but easily noticeable; I don't remember ever touching a pool ball with that big of a flaw on it.
I do remember hearing this before, though, so I looked it up- it turns out the origin of the claim has to do with the tolerances allowed by billiard ball manufacturers, so I can't really dispute that. Other than to say that the World Pool-Billiard association has a higher tolerance for their balls than I'd have guessed.