Curious about the horizon dip: my boat experiment gave me second thoughts

I took a boat out on Lake Michigan last month about 15 miles from shore with a good camera. I expected the horizon to drop steadily as I went further out, but it stayed pretty flat the whole time. The curvature calculators say I should have seen over 150 feet of drop, but my photos didn't show that. Has anyone else tried this kind of test and gotten weird results?

3 comments

3 Comments

jamie_adams11d ago

Hold on, I gotta push back here. You're misreading what you saw. The horizon dip isn't something your eye or a normal camera lens can really catch without doing the math carefully. 150 feet of drop over 15 miles sounds huge but it's spread out over a curved surface your brain just flattens. The boat rocks, waves block your view, and the lake isn't a perfect mirror ball either. I've seen plenty of tests where people line up the horizon with a level on a tripod and it clearly drops away as they go higher or farther out. Your photos don't disprove curvature, they just show you weren't measuring right. You probably confused the actual geometric horizon with the visible one which gets distorted by haze and atmospheric refraction over that much water.

karenb9710d ago

@jamie_adams, how exactly do you separate real horizon drop from the refraction distortion you mentioned when doing those tripod level tests? Seems like the math only works if you assume perfect conditions that never actually happen on a lake. Curious if you've accounted for that variable or just assumed it cancels out.

samk7711d ago

Used to be totally in the flat earth camp on this stuff, not gonna lie. But a buddy showed me a proper surveyor's level test across a long lake and the math actually worked out for curvature. Kinda had to admit my own photos were just sloppy measurement after seeing the real setup.