How far is it to the horizon? How far away can you see an approaching object? This is something I come across in Air Pirates a lot, but it always takes multiple clicks and conversions to get at the simple formula I want. So, fully expecting mathematics to drive away half my audience, here it is (in both kilometers and miles):
So someone 5 and a half feet tall (1.7 meters) would see the horizon disappear about 3.1 miles (4.7 km) away.
Keep in mind:
- These are approximations. Don't be doing science with these numbers.
- These numbers only apply in clear weather.
- You could still see tall objects peeking over the horizon. More info on that below.
Measuring the distance to something over the horizon only requires one extra variable. When the top of the object first peeks over the horizon, you can figure out how far away it is like this:
Now if you wanted to figure out how far away an object is based on how much of it is peeking over the horizon . . . well, you're on your own. I love math and all, but I'd lose the other half of my audience if I did any more of it in public.
Boy, I hope at least one of you cares about this.