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Yes, but if you look out at the world you will notice that perspective causes the surface to ascend in height until the horizon is at eye level with the observer. And if you were to take a protractor you could see that the horizon is at a 90 degree angle to the ground.
Again I have to disagree!
Perspective does not "cause anything", it is only a visual effect. It makes things appear in a certain way.
It is far more accurate to say "that perspective causes the surface
appear to ascend in height until the horizon
appears to be almost at eye level to the observer."
When standing
on the seashore with the eye-level about 5' above sea-level, the horizon is about 3.2 miles away and about 10' below eye-level, but 10' in 3.2 miles is only about 2' of arc.
but when on a 1000' mountain, the horizon is about 45 miles away and about 10' below eye-level, now 2,000' in 45 miles is only about 29' of arc, not noticeable, but quite measurable.
An yes, this "dip angle to the horizon" is real, and quite easily measured. Al Biruni measured the radius by measuring the
dip angle to the horizon as in
Al-Biruni's Classic Experiment: How to Calculate the Radius of the Earth? I gave an extract from that site in
Re: Total area of Earth, but it would be better to read the original.
This reference gives a critical review of Al Biruni's work, including putting realistic estimates on his methods and accuracy in the light of modern knowledge:
AL BASAIR ISLAMIC MEDIA, AL BIRUNI’S MEASUREMENT ON THE EARTHThis video shows measurements of the
dip angle to the horizon up as far as 30,000 ft. I would prefer better equipment, but at 30,000 ft it is quite substantial.
Flat Earth Debunked: The Horizon Always at Eye Level
Simply claiming, without evidence,
"that the line of the horizon is always at eye level with the observer." is not correct.
But, even if it was.
It has nothing to do with the case. At sunset, the eye is at near enough to the same level as the horizon, give or take a few feet, but the sun is still 3,200 miles about your horizon!
According to Rowbotham's Law of Perspective that 3,200 miles subtends an angle at the eye of around 20° (depending on where the observer is).