Usually when Flat Earth Conspiracists try to convince me the earth is flat, I usually ask them these questions:
1. Why do craters exist?
2. Why is the curvature measurable and visible?
3. Why do we have meteorites?
4. Why do we have moon rocks?
5. Why is the exterior shape of the ISS clearly visible through a telescope?
6. How is it that every Astrophysicist, Astronomer, Space Agency Employee, etc. has been lying to you for several hundred years? Surely that’s way too many conspirators.
7. Why is it that the stars have been recorded to have been in an entirely different position in ancient times?
8. Why do iridium flares exist?
9 What reason would all these governments and all these scientists have to lie?
10. Why are asteroids often visible with a telescope?
11. What about matter merely existing would force it downwards if not for gravity?
12. Why can Mercury be seen in front of the sun?
13. Why are the rotation of constellations only consistent with a spheroid earth?
14. What happens with a solar eclipse?
15. What happens with a lunar eclipse?
16. If the moon is so close then why can we only see the same side of the moon regardless of where we are on earth?
17. What exactly keeps the sun and the moon in a constant and perfect rotation?
18. Why is Polaris not seen from Australia?
19. Why does Polaris change its position slightly so often?
20. Why do sunsets exist?
21. Why are objects travelling toward the horizon not observed to be shrinking smaller and smaller, but instead travel over the curve?
22. Why does night time exist? The sun is observed to be spherical, and should therefore emit light in all direction and not act like a spotlight.
23. Why are comets clearly visible even with the naked eye?
24. What are shooting stars?
25. Why was the Antarctic ice wall never recorded?
26. How exactly is there so many people guarding this apparent ice wall?
27. How does the Coriolis Effect work on a flat earth?
28. Why do Jupiter’s moons only orbit Jupiter?
29. Why are planets observed to be exactly what NASA and all those other scientists said it was?
30. What are stars even made of?
31. Why are plane rides to Antarctica approved for anyone who has money?
32. Why do engineers have to account for the curvature of earth when creating long bridges?
33. Why is it that mathematically measurable distances fail on a flat earth?
34. How exactly do lunar phases make sense on a flat earth?
35. Why do Super Blue Blood Moons happen?
36. There’s a phenomena that happens in Hawaii that has the shadows completely vertical. When measuring the shadow angles in different places at this same time you get results only consistent with a spheroid earth. Why is this?
37. Why exactly do you believe the earth has to be flat but not every other planet?
38. Why is it that no flat earther is an actual scientist and why does every flat earther get basic science wrong?
There’s a ton more of these I can come up, but I think this is sufficient for now.