people are smart (because they say so)

they say the earth is flat (because they say so)

therefore smart people say earth is flat (because they say so)

Piss off.

• Why can everyone south of the equator see the exact same stars rotating in the same direction around the same fixed central point in the sky due south of them if they’re supposedly all looking in different directions?
• Why are the distances between degrees of latitude uniform and don’t grow exponentially away from the equator?
• Why does everyone on Earth get the same result for the Eratosthenes experiment, when people nearer the equator should get a much smaller circumference for the Earth than those nearer the poles?
• Come to think of it, was Eratosthenes part of the “round Earth” conspiracy?
• Surviving records show that the ancient Egyptians and Mesopotamians based their astronomical forecasts on calculations assuming the Earth is a globe. Did this conspiracy begin at the dawn of civilization, or are all ancient artifacts nothing but Victorian forgeries? If so, why has this never been detected by modern carbon-dating techniques?
• Why do arc lengths of given angles of longitude decrease rather than increase south of the equator?
• Why does the sun not rise in the northeast and set in the northwest, year round, for everyone on Earth?
• Why DOES the sun set, when the law of perspective states that the angular size of the sun’s altitude, like everything else, can’t become negative?
• Why does the sun’s angular size not change throughout the day or year, since it is “moving toward and away from us” and is “closer than we’re told”?
• Seriously, did you fall asleep during geometry class, or are you just completely demented?
• If you believe in zeteticism, why do you keep relying on magical and unprovable solutions, which can’t be shown to exist with your own eyes and clearly don’t exist at all? Apparently, zeteticism is just code for “make any old bullshit up and pretend it’s true.”
• If all photographs of a round Earth are a hoax, why not simply create photographs of a flat Earth?
• A property of mass is that it has gravitational force regardless of size. If the Earth did not have a gravitational field, wouldn’t that imply that the Earth doesn’t physically exist?
• Where is the Amundsen–Scott South Pole Station located if the south “pole” is the whole circumference of the Earth?
• Wouldn’t creating such elaborate fakes and conspiracies cost an equal–if not greater–amount of money than the science they are supposedly covering up?
• The idea of the Earth as a sphere has existed at least since the time of the ancient Greeks, long before NASA. What were their financial motives?
• What financial motives could NASA have, since their budget is still cut every year?
• How could the sun be a spotlight if it is a sphere? On the flat Earth, the light projection would have to be a semicircle.
• Why does the North Star goes to the horizon?
• Why do constellations appear to be different in the Southern and Northern hemispheres?
• Why is the Coriolis effect stronger near both poles, instead of stronger in the north and weaker in the south?
• If the circumferential south pole is preventing the oceans from pouring over the edge of the flat Earth, why didn’t the oceans disappear during the incredible amount of time it would have taken for that ice to form?
• If the oceans would–if they could–pour off the edge of the flat Earth, where, then, would they go? Does this mean that whatever keeps the oceans on the surface of the flat Earth only operates in a downward direction on the uppermost surface and is absent on the underneath?
• Why are satellites visible from Earth with a pair of binoculars and even the naked eye?
• How could a flat body maintain an atmosphere?
• Why are other celestial bodies spheres but the Earth is not? How, and why, was the Earth created differently?

So you don't have an explanation that matched with a flat earth?