air point about some aircraft like the U2 having flat cockpit windows — I’m not denying that. But here's the thing: even with flat glass, we're still dealing with limited field of view, lens distortion from cameras, atmospheric lensing, and human perception, which can all influence what we think we’re seeing. The eye and brain are not always reliable tools at high altitudes or long distances — especially when we’re trying to discern a curve over an expanse thousands of kilometers wide.
The curvature supposedly becomes noticeable at around 35,000 feet (10.6 km), but the Earth’s size (over 12,700 km in diameter) means that even from that height, the curve would be subtle — nearly flat to the naked eye. That’s why we’re told the best views of curvature come from 20 km+ altitudes, like with weather balloons or higher-altitude flights.
So here’s my honest question: If we can only truly “see” curvature at extreme altitudes — why do people keep pointing to standard airline windows as proof?
It works both ways: just as I won’t take every distorted photo as proof of flatness, we also shouldn’t claim every curved-looking horizon as hard proof of a globe, especially when optics and atmosphere can deceive.
All I’m asking is: is it possible that we’ve all inherited a lot of assumptions — and that questioning them isn’t foolish, but necessary?
I’m not here to argue for the sake of it — I’m here to think out loud. If my questions are silly, they’ll collapse on their own. But if they hold water, I hope they stir up real thought.
