I don't think they are trying to show geometry is wrong here. "it only takes one observation of a horizon not being physical" suggests that the win is having a photograph showing the horizon isn't physical. I don't really know what that means though other than there's no clearly defined horizon in the photograph. Or where the White Swan of all horizons are physical comes from. Not that horizons aren't physical. Holy moly...
Look at the two oil rig pictures in my post (#17
). The curve calculators predicts a horizon closer than the platforms, which is where it normally appears. On the "black swan" photo, the horizon appears behind the platforms (due to strong looming
), which contradicts the calculator.
Just that it's an attack on the globe and makes no claims about a flat earth. It seems to be a tactic by globe deniers for an easy win in an argument.
Yes, that's how most of their arguments work. "Here's something I don't understand, therefore the globe is wrong; if you don't understand it either, you must now trust me when I say that the Earth is flat."
I've seen no FE proof for "water seeks its level" aka that large bodies of water are flat; given that tides exist, it seems to be a proposition that's impossible to demonstrate, yet FEers believe it religiously. Same with "Earth does not move".
But then I already pointed that out in post #2.