But I haven't delegated my source of truth! I have done first hand observation!

1. I regularly do video conferences with friends and colleagues on other continents; I can see if its light or dark in their windows. I have personally verified that some of my friends and colleagues and their places exist.

2. I have seen many ships disappear behind the horizon, and I have seen mountains disappear behind the horizon from ships; I have verified the accuracy of Vesselfinder (by comparing transits through lines in Vesselfinder with what I can see) and checked that it is at the expected distance. (I was curious about the delay.)

3. I have watched the ISS (once even trailed by the ATV) and it was right where HeavensAbove said it would be. And 90 minutes later I did it again. I have personally verified the basic math behind circular orbits.

4. I have experienced changing radio band propagation conditions consistent with a day/night cycle that is different in different places. Such as grayline DX, which is good propagation along the day/night line. Which implies the day/night line is real. And based on the reports I received I know it matches the map. I have built some transmitters and receivers myself.

5. I have flown between continents, been jetlagged and changed my clock's time (or maybe changing my wristwatches time is changing the sun and causing the jetlag?). I have watched the entire flight through windows, so I know I traveled very far.

6. I have seen the motion behind Foucault's pendulum over enough time (I've been to the museum long enough to verify that the pendulum plane rotates as expected, and I saw nobody messing with it in any obvious way.) We also did the same experiment in school. In school, we did the math for the Coriolis force, and talked about how it comes up as a significant factor in unexpected places (e.g. railway). Someone would talk.

7. I've observed the direction of the toilet swirl, and whirlpools in lakes.

8. I've experienced tide levels and swum with/against tide currents (sometimes even in the same place). I have also seen the moon in the sky and I think if it would be inconsistent someone would've noticed by now.

9. I've seen the shape of day/light boundary on the moon. Now that's the moon, but that one's clearly spherical, which is one data point.

10. I had a trusted fried, but he's got a PhD in astrophysics now, so he must be in on it and we cannot be friends anymore. /s

And I'm just some nerd, I haven't done too many experiments. I'm sure I could still extend the list, but of course there's no point since neither of us believe in the flat earth "theory".

There's no intellectual honesty in coming up with fake experiments like flat earthers do (if they even go to the trouble).

Before 2020, I thought flat earth like conspiracies were harmless fun (and I still think that a significant number of flat earthers are just having fun), and maybe they are. But after spending several hundred hours "discussing" many conspiracy theories (people I know and care about started believing very outlandish ones, like chemtrails and 5G causing covid) the last two years, and first hand witnessing intellectual incompentence (complete math illiteracy down to calculating a percentage, complete rejection of the concept of mathematical proofs, zero concept of scale e.g. of organizations and communities, complete refusal to read original research, insisting on "reading between the lines" to interpret texts claims made in texts into the opposite) I have come to see conspiracy theories and fake or un-intellectuality (is that a word?) as very dangerous (the "can cause death" type of danger).