The "flat Earth" theory? is so ridiculous across so many sides; physics, astronomy, common sense! You only have to look at the Sun, moon, and other planets to see that celestial objects are generally spherical. Gravity causes masses to be attracted to their center of mass, resulting in spheres (or spheroids), of molten blobs, or gasseous masses, forming when in space. I don't think people who believe the "flat Earth" theory know that it was put out as a joke, never expecting that people would actually believe it.