If you use gravity to, say, trust your GPS to give you accurate positions and calculate trajectories, then that same force will form material the size of Earth into a ball. ARMYs feel that Suga chose the t-shirt for its satirical punch, which ended up creating a full-circle moment after BTS took a jab at their words being twisted by the media during the concert. Some also feel that the shirt ended up being complimentary to the controversial event that the concert itself had become over the past few months. So if you find yourself talking to a flat-Earther, skip the evidence and arguments and ask yourself how you can build trust. Additional resources

When you follow this train of logic, it becomes clear that the only feasible conclusion is that Earth is indeed flat. Flatter than anyone has ever expected. Engineers and architects also take the Earth's curvature into account when building large structures. A good example is the towers that support long suspension bridges such as the Verrazano Narrows bridge in New York City. Its towers are slightly out of parallel with each other, the tops being more than 1.5 inches further apart than their bases. If the Earth were flat, the bottom of the towers would be separated by the exact same distance as the top of the towers; the planet's curvature forces the tops of the towers apart. If the Earth were flat," Adhikari says, "the trajectory would be completely different." How different depends on which way the globe is sliced into a flattened map, but if it looked like it does on a Mercator-projection map, it might head east and pass over Africa.

And Earth's curvature is clearly apparent from high altitudes, as Capt. Albert Stevensof the U.S. Army Air Corps showed in the 1930s. In December 1930, for example, Stevens snapped a photo looking westward while flying at an altitude of 21,000 feet (6,400 meters) above Villa Mercedes, Argentina.

The question of belief and sincerity is one that comes up a lot," Wilmore said. "If I had to guess, I would probably say that at least some of our members see the Flat Earth Society and Flat Earth Theory as a kind of epistemological exercise, whether as a critique of the scientific method or as a kind of 'solipsism for beginners.' There are also probably some who thought the certificate would be kind of funny to have on their wall. That being said, I know many members personally, and I am fully convinced of their belief."For instance, what’s the tallest supposed mountain on Earth? Everest. Except it isn’t. The name is a giveaway; it’s clearly a morphing of “never rest”, because if you wanted to go to the biggest mountain you’d literally never rest, because it isn’t actually there. What about all those people who have climbed it, you say? Well, consider all the people who have died supposedly doing so. How do you die climbing something that isn’t there? You can’t. They were obviously killed to protect the conspiracy, whereas those who “survived” were willing to play ball. Dean Burnett covers the neurological mechanisms leading to conspiracy theories and more in his debut book The Idiot Brain, You can learn more about the first photographs that clearly showed Earth's curvature in this NASA story. This explainer from Arizona State University lays out clearly and concisely the plentiful evidence for our planet's spherical shape. (Nearly spherical, rather: Earth's rotation causes it to be slightly squashed at the poles and swollen at the equator, a shape known as an oblate spheroid.) And this piece by fivethirtyeight.com explains why people believe in conspiracy theories such as the flat-Earth idea. Bibliography But in reality, humans have circumnavigated the planet in planes and ships, and no one has fallen into space. Rather, when ships traveling large distances on the ocean do appear and disappear on the horizon, they do so either mast or hull-first, respectively. If the Earth was flat, and you had the right optics, you could watch a ship sail from New York to Africa without losing sight of it. You can’t because the curve of the Earth makes the ship dip below the horizon.