TESTING LANG...
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Around 240 B.C, the Greek astronomer Eratosthenes devised a way to measure the circumference of the earth. He knew that each year on the summer solstice the sun would pass directly overhead and illuminate the bottom of a well in the city of Syene, about 500 miles south of Alexandria. On that day, when the sun was at its highest in the south, he found that a vertical stick in Alexandria cast a shadow at a 7.2 degree angle. This angle corresponds to the solar zenith angle – the angle between the sun and the point in the sky directly overhead. He reasoned that the distance between the two cities must therefore constitute 7.2 degrees of a circle, which gives a circumference of about 25,000 miles.
Eratosthenes made two assumptions here: that the earth is a globe and that the sun is distant enough that its rays are effectively parallel. Eratosthenes’ experiment alone does not prove the earth is a globe because his assumptions must be true in order for his results to be valid. Flat earthers reject these assumptions and claim that the sun is much smaller and closer to the earth so that its rays are not parallel. This can produce a 7.2 degree shadow just as easily. In order to find out which is the case, we must work backwards from the underlying logic of these assumptions and see what each of them would entail if true, then we can find a way to test them.
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After arriving at the circumference of the Earth, Eratosthenes is said to have invented a system of latitude and longitude in an ambitious attempt to map it. His experiment would have provided all of the information he needed to do so. All he had to do was wait until the winter solstice and repeat the experiment, in which case he would have measured a shadow angle of 56.2 degrees. Subtracting the 7.2 degrees between Alexandria and the Tropic of Cancer, this gives 48 degrees as the latitude between the Tropic of Cancer and the Tropic of Capricorn. Dividing by 2, this places the Tropic of Cancer at 24 degrees north of the equator (the latitude of the Tropics have fluctuated throughout history and continue to do so today) and Alexandria at 31.2 degrees north.
Modern science places the earth’s radius at 3,959 miles, which gives a pole to pole circumference of about 24,875 miles. Dividing by 360, we find that one degree of arc should be about 69.1 miles on the earth’s surface. That is why lines of latitude are about 69.1 miles apart. So on a globe for every 69.1 miles or one degree of latitude you move north or south of the point the sun is directly overhead, the angle of the shadow would increase by one degree. If Eratosthenes was correct, the angle of his shadow must have been equal to Alexandria’s latitude north of Syene, because that would be the angle that Alexandria is leaning away from Syene due to the curvature of the earth. If three other people were doing his experiment on the same day at 20 degrees, 40 degrees, and 60 degrees north or south of the Tropic of Cancer, they each would respectively measure a shadow angle of 20 degrees, 40 degrees, and 60 degrees, and all would arrive at a circumference of 24,875 miles. The beauty of Eratosthenes’ experiment is that you can do it anywhere on earth, on any day of the year, and arrive at the same circumference. This is where the flat earth model runs into problems.
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In the flat earth model, as a consequence of geometry, as your distance from the point the sun is directly overhead increases, so must the distance between each degree of shadow. If the sun were 3,000 miles above the flat earth, it would be 1,092 miles to the 20 degree shadow, 1,425 miles between the 20 and 40 degree shadows, and a whopping 2,680 miles between the 40 and 60 degree shadows. Someone doing Eratosthenes’ experiment 20 degrees north of the Tropic of Cancer would arrive at a circumference of 19,654 miles, someone at 40 degrees north would get 22,656 miles, and someone at 60 degrees north would get 31,177 miles.
Flat earthers use the Azimuthal Equidistant Projection map, which shows all points at an undistorted distance and direction from the center. Lines of latitude on the flat earth
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have flat earth mapthe same spacing as those on the globe: 69.1 miles per degree. It is for this reason that the angle of the shadow can only be equal to the degrees of latitude between you and the point the sun is directly overhead in one location. Everywhere south of that point the shadow angle would be greater than the latitude and everywhere north of that point, the shadow angle would be less than the latitude. By the time the latitude catches up to the shadow angle, each degree of shadow continues to get progressively farther apart and latitude passes it. The 20 degree shadow would be 15.8 degrees north of the point the sun is directly overhead, the 40 degree shadow 36.4 degrees north, and the 60 degree shadow 75.2 degrees north. Only around 48.3 degrees north would the latitude and angle actually match up as they should everywhere on the globe and only there would someone arrive at a circumference of 24,875 miles. You can change the height of the sun all you like, the latitude and angle will only be the same in one location. Even then, it is only a coincidence due to the random height of the sun, not a direct function of latitude as it is on the globe.
So to recap, if the earth is a globe, the angle between the sun and 90 degrees overhead must be equal to the degrees of latitude between you and the point the sun is 90 degrees overhead in every location. If the earth is flat, this can only be true in one location.
scientific method is the best.
research muna ng madami bago conclude
