(Stars, they say, move in a plane 3,100 miles up.) Like spotlights, these celestial spheres illuminate different portions of the planet in a 24-hour cycle. Earth’s day and night cycle is explained by positing that the sun and moon are spheres measuring 32 miles (51 kilometers) that move in circles 3,000 miles (4,828 km) above the plane of the Earth.

NASA employees, they say, guard this ice wall to prevent people from climbing over and falling off the disc. The leading flat-earther theory holds that Earth is a disc with the Arctic Circle in the center and Antarctica, a 150-foot-tall wall of ice, around the rim. Life’s Little Mysteries explains the main theory: But there are some people today who claim to still believe that the Earth is flat.

They truly believed that the Earth was flat, and before we had satellites and space travel and world traveling, it wasn’t that crazy of a thing to believe.

Long, long ago, people sailing away from their homes worried about falling off the edge of the Earth.

Flat earth theory time zones