My father was a member of the Flat Earth society. He knew the Earth was a globe, but liked the idea of questioning assumptions. Like many (if not most) flat earthers he was just playing devil's advocate - for intellectual amusement, and to make a point about accepting claims on face value. The Earth is verifiably spherical (or oblately spherical, if you want to get technical, but just "spherical" is good enough for most purposes). We can perform simple experiments to verify this (measuring the length of shadows at solar noon in different places), we can make observations which verifying this (the shadow of the earth on the moon being round, buildings and ships vanishing below the horizon), we can note the field of view of the stars changes around the globe. There are hundred of different observations we can do to demonstrate the earth is round. There are none that demonstrate it is flat. And yet there's still Flat Earth advocates. Some do it for religious reasons, some just don't know any better, some are just trolling. I'm somewhat conflicted as to what to do. There is a lot of people just doing it for the lulz, people who are just trolling. Obviously it is pointless to engage such people. Then there's also some who believe it because of religion, or have some kind of mental obsession with the world being flat, regardless of science. Again, not a lot of point engaging them. But is it possible that there are people who are genuinely interested in the question, but simply have not figured it out yet. People who have just made a few mistakes in their understanding of the science or the math - or who have been suckered in by glib arguments? Are there people for whom it would be worthwhile actually expending some effort in debunking flat earth arguments? Flat earth arguments are kind of fun to argue against, as they often involved simple math, and they are obviously wrong. So it seems like low hanging fruit. So debunkers often end up getting into quite long discussion on the topic. But I feel that is is largely wasted effort, because the people they are arguing with are either trolling or mentally stuck. And the people who would benefit from the argument (if they even exist) are not reading. So I discourage Flat Earth discussion on Metabunk. There's some threads on the math of how much the curvature of the earth obscures things, as that's nice pure math. But really that should be all people need. If they can't see that the curvature of the Earth actually does obscure things, then is there really any point in rebutting their other points? To keep up the signal to noise ratio on Metabunk, I plan to continue to discourage Flat Earth discussion unless someone can explain why I should not. I encourage people who would like to debate flat earthers for fun to stop, or, if they insist, go the Flat Earth Society Forums, where there are plenty of willing people. I'd be interested to hear personal stories. Did anyone used to troll as a Flat Earther? Did anyone think the arguments held water, but then figured it out? Does anyone believe in the Flat Earth model, and think I'm being unreasonable. And for the honest flat Earth believers, some guidelines. Yours is an extraordinary claim, and as such it requires extraordinary evidence. Do not expect others to do the heavy lifting for you. You need actual evidence, not just your personal opinion. This evidence should include measurements, and math. For example, if you think the horizon is always at eye level, then you would need to demonstrate this - for example by calculating the amount of expected drop from some place, and then showing a detectable difference from this amount. If you think high altitude photos don't show enough curvature, then you need to calculate what the curvature should be, and measure how much it differs. If you cannot provide this evidence, then please do not post here. [Update] I wrote the above some time ago, and since then have allowed more Flat Earth discussion on Metabunk, simply because there seems to be more genuine interest.