Member 6L6 and I were amusing ourselves listening to the SR71 "Los Angeles Speed Check" audiotape, when I realized that a teeny fragment of it sounded, to me anyway, just a little questionable.

The SR71 pilot casually says he was directly over Tucson AZ and could see the skyline of Los Angeles CA out the window. Which seemed, um, improbable.

So I hired an 11th grader to work out the trigonometry of the situation, and make a plot of (distance to the horizon) versus (flying altitude). Result is below.

To my surprise, Google Maps says there are 484 miles of Interstate road (which is certainly NOT a perfect straight line) from Tucson to Los Angeles. While the plot below says the horizon is about 500 miles away when you're flying at a comfortable spyplane altitude of 16 miles. So it's quite possible. Golly!

Note: earth is assumed to be a sphere of diameter 7900 mi.

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The SR71 pilot casually says he was directly over Tucson AZ and could see the skyline of Los Angeles CA out the window. Which seemed, um, improbable.

So I hired an 11th grader to work out the trigonometry of the situation, and make a plot of (distance to the horizon) versus (flying altitude). Result is below.

To my surprise, Google Maps says there are 484 miles of Interstate road (which is certainly NOT a perfect straight line) from Tucson to Los Angeles. While the plot below says the horizon is about 500 miles away when you're flying at a comfortable spyplane altitude of 16 miles. So it's quite possible. Golly!

Note: earth is assumed to be a sphere of diameter 7900 mi.

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