The difference between misinformation and disinformation is the difference between ignorance and malice. Trolling is somewhat different,

Charles Petzold: Very Wrong Math

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2025-01-10 23:30:16

The difference between misinformation and disinformation is the difference between ignorance and malice. Trolling is somewhat different, incorporating an element of provocation and narcissism. But what the hell is this?

This was posted by a design and construction company that Facebook thinks I should follow. A cursory glance at their other posts reveals nothing quite as egregiously wrong. So I’m confused. Is it supposed to be a joke?

Let me ignore the “flight time” part of the problem and focus on the length of those two arcs. The length of a circular arc is proportional to the subtending angle and the radius of the circle, specifically:

The angle for the two arcs in the illustration is the same, but in calculating the length of those arcs, the radius of the earth has to be taken into account as well as the distance above the surface of the earth. If the radius of the earth is R, then this illustration implies that:

That’s a distance in feet! That would make the circumference of the earth a bit over 5 miles, which is considerably less than the actual circumference.