Note that this was a resurrection of an old thread.
There are multiple definitions of smoothness, one of them defines the maximum deviation from average height, others adjusts for the fact that "roughness" can be felt at very small height differences if the angle of the slope is large enough.
With the hair, the slope is very steep, which is why the hair is so easily felt, if at the other hand that same difference in diameter is the difference along the axes of an ellipsoid, no one would be able to feel it.
The Himalayas are spread over a fairly large area and Everest doesn't really poke that far above the surroundings. I doubt it would be possible to feel it on a cue sized earth.
Kilimanjaro on the other hand might just be noticeable as a feelable dot.
Reductionist and proud of it.
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