A question that I believe sums it up nicely in comment constraints: Pythagoras inferred that the Earth must be round–would you have believed him back in the day, and why or why not?

I have pondered this myself as best I could whilst not being “back in the day”. So, I decided to start by chucking out all the repeated rhetoric and empty words about a round earth, as rhetoric and empty words too led to folks believing in a flat earth. So, toss out stuff like: “The earth is round because I say so”, “the textbook says the earth is round”, “flat earth? Come on, guys.”

I have since come to a reasonably assured, common sense answer to that question. One could argue that “If the earth were flat, we could see unobstructed.” Okay, it makes sense, but it needs to go farther than that. You can go out and take a look, but it still LOOKS flat. So, what you can do is get a large ball, tape something to one side, and slowly roll the ball over and watch the item sink out of your vision. Now, get on a ship and sail away from land, and watch it do the same thing.

That’s enough to convince me, without all the pointless rhetoric. Now, you can also say “Satellites have shown the Earth to be round” but two things: I said “back in the day” and also “implanted images?” are a possibility.

Anyway, the point of all this was that some of those people calling space aliens and stuff impossible right off the bat would probably have called Pythagoras a nut job were they in his time, for the same reasons.