The flat-earth conspiracy theory has been debunked by scientists and astronomers time and again. Earth is not flat, it is round.
Earth is quite round, a near-perfect sphere. If one leaves Earth's surface, it's impossible not to see the Earth's true shape, and observe our planet's curvature. Astronaut photographs from space and the fact that round-the-world travel itineraries work is all proof that Earth is round. In an article, Live Sciences has listed seven things we can do to prove that Earth is round, including watching an eclipse or getting a weather balloon.
In an episode of Cosmos, Carl Sagan, an American astronomer, easily proved the Earth was a sphere using cardboard, some sticks, and the work of an ancient Libyan-Greek scholar, Eratosthenes of Cyrene who debunked flat-Earth theories more than two millennia ago. Furthermore, Bill Nye, famous as Bill Nye the Science Guy, suggests that if the Earth were flat, one should be able to use a high-powered telescope to view Europe from the East Coast. Flat earthers could claim victory by setting up this experiment. But no flat Earther has ever done so, because Earth's sphericity hides Europe and North America from each other.