[philman_36]

The rate the earth curved downward is 8” to the mile.

Wrong. The formula is 8" per mile squared.

Even Alexa knows that...What is the curvature of the earth per mile?
The Earth has a radius of approximately 3965 miles. Using the Pythagorean theorem, that calculates to an average curvature of 7.98 inches per mile or approximately 8 inches per mile (squared).

At three miles the drop is about 6 feet. You aren't going to get that with your formula.

[mad_as_he$$]

Every serious sniper knows that! ;-)

[Jonty30]

What is the difference between a mile and a mile squared?
They are both one mile long.

[Telepathic Intruder]

Wrong. The formula is 8" per mile squared.

Wrong again. That is a parabolic function. The earth is a sphere, not a parabola. The formula for circle is R²=X²+Y².

R (earth's radius) is about 4,000 miles, so using miles, CURVATURE=4,000 - (square root of (16,000,000 - distance²)).

It just happens to be that 8" per mile squared is a good approximation using small distances.

[21twelve]

Driving across Montana with my daughter we were trying to guess how far we could see. We took a guess at the mountains ahead and we were pretty close at 15 miles away (within 1 mile).

I thought the horizon on the ocean was 11 miles away - so thanks for the correction that it is only 3 miles away. I’ll have to tell her that. She thought it would have been much farther than 11 miles (I told her that I wasn’t sure!), so I suppose she will be sorely disappointed that it is only 3!