If you assume FET is true and apply basic (10th grade) trigonometry to the distance and elevation of the sun, you come to results that seem to contradict everyday's observation. My computations start from the following assumptions:
1) Earth is flat
2) The equator has a radius of about 6000 miles
3) The sun rotates at a height of 3,000 miles above sea level.
4) At equinox, the sun cycles over the equator, and the illuminated area touches the pole. (Its radius is hence about 6000 miles)
5) The sun is a sphere (sorry, McIntyre) with a radius of 16 miles
So, let's consider an observer at dusk - the moment when he is at the border of the illuminated zone. (We RE'er call this "sunset", but I'm not sure whether the sun is
supposed to set in FET.) The observer is thus 6000 miles away from the center of the illuminated disk, and the sun is 3000 miles above this center. Let's draw a picture :
1st Question: What is the (angular) elevation of the sun above the horizon ?A simple trigonometric calculation (red triangle) tells us that the sun is actually 26°
above the horizon - that's more than a quarter of all the way up to zenith ! This does not really correspond to what I'm seeing each evening.
2nd Question: What's the sun's angular size at this moment ?Pythagoras tells us that the distance to the sun is about 6700 miles. When we apply a computation similar to the one above to the green triangle, we get a half-angle of 0.137°, hence an angular size of 0.274°. To compare, the thumb on a stretched arm has roughly an angular size of 2°, as everybody can easily compute - that's more than seven times as much ! Again, the result does not correspond to everyday's observation.
Note that the same consideration holds for the moon which is supposed to rotate at the same altitude and is easier to observe without a blackened glass. Besides, it's easy to observe details on the moon's surface, so the size of the moon cannot be explained away with a "glow effect".
(Note also that a similar consideration holds if the sun is a disk - only that under this angle it would appear as an ellipse, which does - again- contradict observation.)
Logic dictates that if my assumptions lead to results which clearly contradict observation, the assumptions are false.
Now I'm
really curious what couter-arguments you FE'er might find.
(Edit: Modified spelling errors ("It's" instead of "Its"; "0,137°" instead of "0.137°", centred image.)