Horizon Rises up Instead of Receding
Flat earthers claim if we are on a globe one would you rise up from the globe the horizon would lower. They note that when flying on an airplane perhaps ten miles up when you look out the windows you see the horizon rising up to the center as you would see it on earth.
This is quoted as one of the primary proofs the earth is flat.
“Whether at sea-level, the top of Mount Everest, or flying over a hundred thousand feet in the air, the always horizontal horizon line always rises up to meet the eye-level of the observer and remains perfectly flat. You can test for yourself on a beach or hilltop, in a large field or desert, aboard a hot-air balloon or helicopter; you will see the panoramic horizon ascend with you and remain completely level all around.
“If the Earth were actually a big ball, however, the horizon should sink as you ascend, not rise to your eye-level, and it would dip at each end of your periphery, not remain flat all around. Standing in a rising balloon, you would have to look downwards to the horizon; the highest point of the ball-Earth would be directly beneath you and declining on each side. ” (Eric Dubey)
In reality if you rise up 10 miles above a globe with a diameter of about 8000 miles you can not expect to see anything very much different in regard to the horizon level than when you were are on the ground.
So this is probably not a valid proof the earth is flat. Because we can not go up high enough to see the globe. Presumably if you could go higher the horizon would lower and gradually the globe earth would come into view as you get further away from it…
You can see the horizon without flying extremely high. Take a photograph of the horizon, together with a water level. Best not on the beach but on a few 100 m high cliff, since the calculated horizon dip is very small. But visible, perhaps after enlarging your photograph. But realise that we are only talking about fractions of a degree. Only at 10 km the dip becomes about 3°, still difficult to distinguish without a reference level, like a theodolite(-app).
But anyway, do the experiment and find out yourselves: the horizon never rises to eye level, but always shows the correct, however tiny, dip.
https://www.metabunk.org/threads/water-level-showing-mountain-and-horizon-dip-due-to-curvature.9203/#post-229617
Rubbish. Horizon is a result of perspective. Nothing to do with the dip. It will never dip because perspective is the way we see things. It means what we see is not the reality. What we see is the earth rises up as the distance increases and the sky comes down. So there is a point where they meet, that is the horizon, or in perspective terms, the vanishing point. So when things reach the vanishing point they disappear from our view. But they do not disappear. It is only optics, perspective.
So there is no dip. The ground will always come up and the sky will come down, due to perspective.
But this is not reality, it is an illusion, what we see is an illusion. So we can not make any conclusions based on our sense perception, because our sense perception is not correct. We see the earth coming up and the sky coming down to meet at the horizon, but that is not real, it is an illusion.
What you describe is the theoretical horizon with an infinite flat plane. Like the painters since the 15 th century or so used. For relatively short distances a perfect tool for painting. But on a larger scale it should be obvious from a simple drawing, that on a sphere your line of sight forms a downward tangent to the surface, and from where it touches the surface you cannot see the surface beyond that point. That is what we call the real or visible horizon. With the help of simple goniometry you can calculate at which distance the horizon lies and what dip it should have. And again, photographs with a reference level clearly SHOW this dip. Do the experiment!. It is even one of the (wrong) arguments of flat earth proponents, who claim on a globe the horizon should show a dip (which is correct) but, as they say, always rises to eye level (which is wrong).
RUBBISH! The horizon is a result of perspective. That is how we see. It has nothing to do with the curve of the earth. If we were seeing the curve of the earth the ground would go down, but the ground goes up, when the earth is curving down.
The horizon is the vanishing point produced by perspective. It has NOTHING to do with the curve of the earth, and it is working in the opposite direction to the curve of the earth anyhow, so it can not be the curve of the earth.
The ground DOES go down. That is the horizon dip. Use a (water) level. Make a photograph. Do the math. The observations match the predictions for what we should see on the globe.
https://flatearth.ws/water-level-horizon
The ground does not appear to go down. The ground appears to come up to the horizon. If you were actually looking off a globe then there would be no horizon. The ground would go down as the globe drops away. But we don’t see that. We see the ground coming up to the center of your view. That is due to perspective. And because of this perspective view you have no way actually of telling what the ground is doing.
You don’t see it as you would see looing off a globe. You see the ground coming up to the meet the sky in the center.
So you see ground coming up and sky coming down. But that is not the way it is. Ground is not coming up and sky is not coming down.
So this is how what we see is created. It is created by perspective. It has nothing to do with the shape of the earth. There is a circular region of the sky that we are viewing and things come into our view at the horizon on one side, they come up to their highest point above our heads and as they move across the sky they come down again to the horizon on the other side.
But this circular region of the sky we are viewing has its appearing and vanishing points around the horizon.
So this illusion of things rising on one side and coming up to the center and then going down on the other side and setting, it is just an illusion created by perspective and the vanishing and appearing points around the edge of the circular portion of the sky we are viewing.
When you start looking at your feet and want to look further away, then you will have to raise your head and your eyes. That is obvious. You may call that “the ground appears to come up”, if you like. This is the case for a flat plane but also for a curved plane or even for a slightly downward slope. The observable difference lies in up to how high you go before you reach the horizon. On a flat surface the horizon goes up to “eye level”(and lies in infinity, according to perspective theory), for which your reference can be a water level or a theodolite(-app). For a spherical surface with the size of the Earth the horizon will appear to lie slightly below that level (we talk about the dip-angle) and at a finite distance. Both dip-angle and horizon distance can be calculated with the help of geometry and a little math, depending on the observer’s height (or elevation). For h = 2 m the dip-angle is 0.04°and the distance is about 5 km. For 20 m the dip-angle is 0.13° and the distance is 17 km. For 200 m the numbers are 0.4° and 55 km. For an airplane at 10,000 m you have 3° and 385 km.
A photograph of the horizon together with a water level or a theodolite(-app) or any other way to show the reference (eye)level shows this dip-angle, but it will be better visible the higher your viewpoint is.
So many words saying nothing…
The reality is the horizon distance is a mystery to science. This is one of the known problems in science. The calculated horizon distance, based on the earth being a globe, and calculating the horizon distance according to that, it never works properly. And actual scientists know that.
The reason this does not work is the horizon and the vanishing point at the horizon are created by perspective, it is an optical illusion. And we are only able to see in this optical illusion of perspective. We are unable to see things as they are. Therefore any assumptions we make, based on our imperfect sense perception, will be faulty. Because we can not see things as they actually are. We see in perspective, but the things are not in perspective actually.
Things don’t appear to us as they should on a globe for sure. We can not see the curvature of the globe for sure. But we would not see it anyhow, because we see in perspective. We can not see actually how things really are…