Monday, August 23, 2021

Back to the back of the envelope

Okay, these are just rough calculations, but I figure the total irregularity in our planet’s surface, measured as the sum of the height of the highest mountain and the depth of the deepest trench, to be about 20 kilometers against a diameter of around 12,750 kilometers, a ratio of roughly 638 to 1. Roughly is the wrong word though, because it’s pretty darn smooth. If the Earth was the size of a billiard ball the textural variation would be something like 0.1mm. Mount Everest and the Challenger Deep would be equally indiscernible when you rubbed your thumb across the world.

2 comments:

Mikey said...

Actually, .1mm is just under .004 inches. About the thickness of a single sheet of 20lb paper. Not quite an Alpine precipice, but easily felt with a human finger.
Still pretty smooth though.

Dave Maleckar said...

Yeah but. The edge of a piece of paper would be a 20 km vertical cliff at scale, which there ain't none. We're talking about the extremes of irregularity on a nearly perfect sphere, the world shrunk to cueball size.