The flat earth conspiracy theory really made me reevaluate how difficult it is to prove just about anything. As best as I can tell, the easiest way for one person to independently verify the earth is not flat is by watching the hull of a boat disappear before the mast. That's not super conclusive in my opinion because it relies on looking at an object over a couple miles away. This realization evaded most of mankind 600 years ago, so I'd argue it's not overwhelmingly obvious. Similarly, the curvature of the earth isn't observable from a commercial airline flight's standard altitude and window construction.
This is all to say that people refuse to believe things that they cannot personally verify. For the record, I believe the earth is an oblong spheroid.
You can see the same effect on land with a tower and an open plain. Also you can observe the shadow the Earth casts on the moon during a lunar eclipse. It's actually been known since antiquity that the earth is round, though I don't know if most of mankind knew that or if they would have cared.
If you're referring to Columbus with the 600 years ago statement, he actually did some dodgy math to say the Earth was much smaller around than others thought which is why he thought he had a shortcut to India. He would have perished had he not had the good luck to run into a whole other continent that just happened to be in the way. To me the craziest aspect of all of that is that somehow we still refer to Native Americans (somewhat pejoratively) as Indians based on a half millennia old mistake.
> You can see the same effect on land with a tower and an open plain.
On land, you could attribute any observed curvature to geology. On water, there does not seem to be any other way to explain curvature. I see parents point about how personally verifying is both essential to some (many?) of these critics, and quite hard to do rigorously.
It's not quite that easy. One could suppose that light falls due to gravity. So the light from the bottom of a far-away ship falls into the ocean before it reaches you, leaving only the top of the ship visible to you.
I vaguely recall that historically the round shadow of the earth during lunar eclipses was one good piece of evidence.
> If you're referring to Columbus with the 600 years ago statement
Indeed I was but not necessarily him specifically, but the average Javascript engineer at the time.
I was just now reading about Eratosthenes[0], to check my priors because I had been taught some people had speculated it way earlier. The article claims:
> By around 500 B.C., most ancient Greeks believed that Earth was round, not flat
That surprised me. But, here I'm stuck thinking how difficult is me to verify that claim. I'd probably need a few years of Classics and then access artifacts that are one thousand years old. I can totally understand how earnest skepticism unravels into madness.
Carl Sagan talked about Eratosthenes in Cosmos[0] actually which is what I was thinking of. He was also able to make a good estimate of the size of the Earth as well. The video has a good explanation of how it was done.
This is all to say that people refuse to believe things that they cannot personally verify. For the record, I believe the earth is an oblong spheroid.