What have I done?
Actually it was my friend's fault. He was doing some historical research and went looking for the height of a particular lighthouse.
Some of you may see this one coming.
Of course he stumbled onto a bunch of flat earth websites, and from there wandered out to some YouTube channels. And now he's turned me on to some of them.
Have I ever mentioned how much I miss the Apollo Hoaxers? Flat Earther Bingo is So Boring.
Here's some of their big arguments:
1) Rivers would have to run uphill (because they'd have to go around the curve of a round Earth, see?)
2) Planes would have to be continuously pushing the nose down lest they head off into space.
3) Tides are impossible because the water would be sucked into space (but the Moon should have fallen down anyhow so never mind).
4) Airplanes (seriously...have they ever been on one?) would have to steer madly clockwise the instant they left the runway, and keep doing that until they crossed the pole and had to steer counter-clockwise to continue compensating for Earth's spin. Oh, and if you jumped up you'd go flying into a wall.
The lighthouse one is actually half-way, err, something. They look at tables of how far out from sea you should be able to see a particular lighthouse, then proceed to get the math wrong in calculating the actual visibility. I keep wanting to ask them, though; Why Build Them Tall in the First Place? Unless, you know, round earth (which they charmingly call "Ball Earth." It's their version of "Astro__."
