I’m visiting my grandmother on the way down to the Mid-Atlantic city I’m moving to and the discussion of how far one can see standing on flat land came up. The average answer is around 3 miles and it’s figured out with this equation:
(r+h)squared = r squared + d squared
Solving for me at 5’7″, that’s…
(3961.301)2 = (3961.3)2 +d2
15691905.612601 = 15691897.69 +d2
d = 2.81471
So standing on flat ground at no elevation, I can see about 2.8 miles.