I am afraid of this radicalism. But it is different to a hollow earth theory. Hollow earth makes sense while flat earth does not.
Even though I naturally find it hilarious anyone would be serious the earth is flat. I still want to take them seriously because I only care about sensible things so if they have reason to believe it then lets think about it and give them a chance.
First when you look at the moon and sun. Why is it round then? If the moon and sun is round there's a good chance planets are round. And it's unlikely that both moon and sun would be facing the right way if it was a flat disc.
From first hand experience this is sadly the only evidence I can offer and it is circumstantial.
I have not gone out of my way to know for sure. Let me think about it...
Lets say any photo can be faked although it's probably unlikely. Lets say all photo are unreliable.
I have never flown in a plane in a straight line so I can't say anything about that either.
I lack the means to prove it from first hand experience. The good thing is I am able to know that. Others don't know the difference between first hand experience and what is passed on to them from sources not fool proof.
It's safe to assume for me the world is round and hollow. I could be wrong. For now that's what the information is telling me.
From first hand experience that's all I can say about it.
Now I'm curious how to prove it to myself actually.