Tomorrow is the summer solstice, the longest day of the year in the northern hemisphere. Round earthers believe that the earth is tilted in it's axis as it orbits the sun and this accounts for the change of seasons. Flat earthers, however know this to be a lie, probably the work of Satan, and have their own explanation.
Flat-Earthers agree that the sun perfectly circles the ring of the equator on the equinox; however, to account for the equal hours of daytime and nighttime, the models make a few tweaks to how the sun itself looks and behaves.
While you might envision the sun as an enormous ball of exploding gas located 93 million miles (150 million kilometers) away, a flat-Earther would see it as a teeny, tiny spotlight hovering just over the Earth. How teeny and how close is it? According to the early flat-Earth thinker Samuel Birley Rowbotham, who published the influential treatise "Zetetic Astronomy: Earth Not a Globe" in 1881, the sun is only about 32 miles (52 km) in diameter and hovers anywhere from 400 to 700 miles (640 to 1,130 km) above the Earth, depending on the month.
Many modern flat-Earthers now believe that the sun sits about 3,000 miles (5,000 km) over the Earth, but Rowbotham's general idea remains popular in the community. Here's how members of the Flat Earth Society (one of the foremost flat-Earth activist groups in the world) describe the idea on their official wiki page:
"The sun moves in circles around the North Pole. When it is over your head, it's day. When it's not, it's night. The light of the sun is confined to a limited area, and its light acts like a spotlight upon the Earth."
The diameter of these sun-circles governs the seasons. According to one popular theory, the sun circles closest to the North Pole in June, then spends the next six months spiraling slowly outward toward the ice wall at the edge of the world. In December, the sun reverses course and spirals back inward again. During the spring and autumn equinoxes, the sun circles in a perfect loop around the equator, casting light on half of the disc world at any given time. Voila: seasons!
This explanation has its problems. For starters, a sun circling 3,000 miles (5,000 km) above a flat Earth would never actually "set," even at the most southern latitudes. YouTube user Wolfie6020, a globe-Earth proponent, demonstrated this by building a scale model of the flat-Earth-style sun as it would be seen from Sydney on a vernal equinox. As shown in his video, the sun (actually a drone carrying a ping-pong ball) never dips below the horizon, even at its farthest point from the observer.
Moreover, during an equinox, the sun appears to rise due east and set due west everywhere on Earth except at the poles. For this to hold true on a flat Earth, where some cities are physically many times farther away from the sun than others, the sunlight would have to bend at hundreds of different angles simultaneously. That's the only way it could appear as if it was always coming from the east.
So far, no flat-Earth model has been able to resolve these problems. But that doesn't stop the community from trying — or, in some cases, not trying. Like many
conspiracy theories, it's the uncertainty that makes flat-Earth theory a mystery worth obsessing over for its proponents. So, whatever you believe, we hope this year's solstice restores your wonder in the globe/disk we call home.
https://www.livescience.com/63648-flat-earth-explanation-for-the-equinox.html