The horizon always appears perfectly flat 360 degrees around the observer regardless of altitude. All amateur balloon, rocket, plane and drone footage show a completely flat horizon over 20+ miles high. Only NASA and other government "space agencies" show curvature in their fake CGI photos/videos.
The horizon always rises to the eye level of the observer as altitude is gained, so you never have to look down to see it. If Earth were in fact a globe, no matter how large, as you ascended the horizon would stay fixed and the observer / camera would have to tilt looking down further and further to see it.
The natural physics of water is to find and maintain its level. If Earth were a giant sphere tilted, wobbling and hurdling through infinite space then truly flat, consistently level surfaces would not exist here. But since Earth is in fact an extended flat plane, this fundamental physical property of fluids finding and remaining level is consistent with experience and common sense.
I think this is one piece of evidence that at least SOME "Flat Earthers" have zero sense of humor. He didn't even acknowledge the joke! He acts like a bot programmed to convert the world to flat earth. I'm not saying he is a bot, but if there
were such a bot, it would act the same way: ignoring any humor, staying 100% on task, always working on
the mission to convert the world.
I post a joke, and here "Truth is Eternal" dives in to Flat Earth argumentation. Give me a break! Chill out already. You take your pet crusade FAR too seriously.