The autumn equinox is upon us. On Saturday (Sept. 22), the sun will shine directly on the Earth's equator, autumn will officially begin in the northern hemisphere, and the length of day and night will be nearly equal across the globe ... or, "across the disc," if you're a flat-Earther. For flat-Earthers — the vocal online community of folks who believe the world is actually flat and science is a conspiracy — the equinox can be tricky to explain. Without axial tilt, the phenomenon in which the rotating, spherical Earth angles its poles toward or away from the sun, how can the changing seasons be reliably explained? How can sunrises and sunsets occur if the sun is constantly shining on the entire, flat surface of the planet? If the North Pole sits at the exact center of the world, can compass directions even exist?
