200 Proof: The Curved Horizon


1) The horizon always appears perfectly flat 360 degrees around the observer regardless of altitude. All amateur balloon, rocket, plane and drone footage show a completely flat horizon over 20+ miles high. Only NASA and other government “space agencies” show curvature in their fake CGI photos/videos.

I of course shared a picture from the international Space Station of the Mediterranean Sea. The International Space Station is a modern marvel that orbits the earth at 250 miles above the oceans. The flat Earthers like to claim that it is a fake, but they do make pretty convincing photos, and an amateur astronomer can see it with a telescope. If the photos of Earth from Earth are fake, I would ask where are the pictures of a flat Earth? I have yet to see one photo. Flat Earth sites have only drawings and paintings.

Even with overwhelming photographic evidence, there is the concern that the horizon does not appear to curve. The truth is the Earth is an enormous ball with a circumference that is 24,000+ miles. To drive around the Earth in a car going 100 miles an hour would take 10 days along any of the great circles (even traveling North/South). Because of the large nature size of Earth, the curve is almost imperceptible.

In order to perceive the curved horizon, two conditions are required. (1) The horizon must be unobscured with sufficient field of view. No trees or mountains in the way and more field of view than out of a small port window. (2) The observer most be sufficiently high enough to see enough of Earth that a curve would be expected.

For an understanding of this, imagine an near infinite spherical planet. In order to be so large, the curve of the planet would have to approach a straight line. To demonstrate this in another way look at the following circles and notice the sharper curve in the smaller circles:

concentric circles

Each of the black lines is a circle–even the largest blue one in the farthest background. This image was built in PowerPoint using circles of the following diameters: 0.25″, 0.5″, 1″, 2″, 3″, 4″, 5″, 6.5″, 7.4″, 50″, and 200″. It is difficult to see the curve in the 200″ circle, because it has less curve than the smaller circles. Now imagine a circle with a 2.5 million times bigger than that largest circle (diameter of 8,000 miles). It would be very flat. In fact it would have so little curve, that at small scales of about 300 miles you could use the horizon to approximate a straight line.

The higher elevation an observer is, the more of a sphere he will see. This is why am observer sees further away as he started out the window of an airplane climbing to altitude.

From Mount Everest (5.5 miles of elevation), an observer can only see 300 miles away. Below is a scale drawing of a spherical planet with diameter 7,900 miles. The small circle on the right is the 300 mile viewing radius an observer would see if Mount Everest were surrounded by an ocean (in fact it is surrounded by other mountains that obstruct the horizon). Even with an unobstructed horizon, when zoomed in, this is very flat looking::


From an airplane flying at the highest altitude used by a Concorde (no longer in service), an observer would only just begin to see the curved horizon (without clouds in the way and as much view as possible pressed against the window glass). This is the scale of a plane flying 7.7 miles elevation with a 350 mile viewing radius:

From the International Space Station, astronauts (and cosmonauts) can see in any direction 2000 miles from their 250 mile high perch. It is difficult not to notice the curvature from this height:

The photos flat Earthers really like are the ones cropped in some way that show how flat the Earth is from the International Space Station. Unfortunately, cropping out part of the view will just show what would be seen at a lower elevation:

Or these 3 photos of flat earth from the ISS:

split photo

It isn’t difficult to do this with a globe either. This is a photo of a globe taken with my cell phone with the camera as close to the globe as I could get it:


Where is the curve in the horizon? It is everywhere.




6 thoughts on “200 Proof: The Curved Horizon”

  1. Hi
    You are right about having to have distance in order to see the curvature. I am not a flat-earther but I have wondered about several things relating to the globe earth since I was in my teens.

    If the earth is rotating at 1000 miles an hour at the equator, how is it that the atmosphere moves as a unit with the earth. Simple gas mechanics will tell you this is not possible. The atmosphere closest to the earth would move the fastest and the atmosphere would move progressively slower as you moved away from the earth. The atmosphere should describe a spiral just like galaxies. The particles on earth must obey the same laws of physics that galaxies follow. Yet this does not happen.

    I also wondered when I was young, why you couldn’t float just a few yards from the ground and wait as the rotating earth moves under you, faster and faster until the earth should be going at 1000 miles under you, (subtracting for wind resistance). When hot air balloons were first launched in France, many scientists believed that they would be able to travel like I said, hang in a baloon and wait for the earth to “bring” the location to you.

    One last thing that bothered me as a teen, was about flight times that are almost identical traveling either east or west. As soon as a plane leaves the earth, it is no longer part of the inertial system of the earths spin. Being freed from that inertia, it becomes an independently moving object and its speed would become more and more different, relative to the earths rotational speed. If the plane just circles in the air long enough, the earth should rotate at 1000 miles an hour under the plane, at the equator. This additional or subtractional speed MUST be accounted for in engineering but it is not, perhaps because it does not exist. This is basic physics and no amount of words will change that.

    Have you ever wondered where the camera is when you see video of the ISS. It hangs in space, there is no pole or other attachment to the space station. Also notice that when the ISS flys over the night-side, there are no clouds in the sky. This is just not possible over such a large area of our planet.
    I just picked a video at random from the ISS. This one below shows aa hot-spot from the sun on the left side of the earth. The sun would not creat such a bright spot from 93,000,000 miles away because all of the light waves would be parallel by the time they reached the earth. This is basic physics and the CGI looks like how someone not familiar with physics would draw it.

    I am not a flat-earther but there are many questions that NASA and the “evidence” need to answer or at least clarify.


    1. Thank you for the reply. The video link you included does not work.

      Regarding your unit of atmosphere moving with the Earth: the movements of the atmosphere are quite complex. They are affected by heating and cooling which causes winds. But on average, you are correct that the atmosphere moves as a unit with the Earth. This movement is first of all because the atmosphere is bound to the Earth by gravity. This is the same thing that binds stars together in a Galaxy. The movement as a unit is because of friction. The surface of the Earth, then the denser layers of atmosphere, pull along the layers above them through friction. Because of temperature changes resulting in winds, velocity increases at first. However, as density decreases and gravity’s effects weaken secondary to increasing distance; the atmosphere’s velocity does in fact slow. Unlike a galaxy, the air is very thin and not in the visible spectrum, so you do not see the spiral effect, but it is there.

      You could float above the ground and wait for the Earth to move under your feet. The problem is whether you jump or float up in a hot air balloon, you have inertia equal to the ground under your feet, so the Earth would stay in the same location as your feet. Inertia just means that an object won’t accelerate without a force. A plane taking off can’t just float because of the same reason. Inertia means as soon as it takes off it is moving at 1000 miles per hour plus its takeoff veloicty, the same as the surface of Earth plus the take off velocity. The inertia system is not quite as you describe it. Another example would be riding in a train moving at 60mph and throwing a ball forward to a friend at 10mph. Your friend would catch the ball with no problem. The ball does not leave the inertia system and hit the back of the train at -50mph.

      If you want to see the ISS you can do so. Here is how: http://www.telescopeking.com/guides/how-to-see-the-space-station-with-a-telescope/

      I’m not sure what you are referring to with the “hot spot” since your video link is not functioning. I would point out that the space station is still in the atmosphere though, and light waves would refract, particularly closer to the Earth.


      1. I know that scientists say that the atmosphere moves as a unit with the earth but this goes against the laws of gas mechanics. Gravity is one of the weakest forces in the universe and gravity cannot move gases as a unit like solid matter. If the earth was spinning at 1000 miles an hour at the equator, our atmosphere would describe a spiral just like a galaxy. There would be no winds because the speed of earths rotation would be faster than any wind could possibly blow. The gas closest to the earth would move the fastest and the atmosphere would ‘drag’ behind getting progressively slower and slower. This is basic physics and basic gas mechanics and nothing can change this.

        And about the plane. The plane is part of earths inertial system only when it is on the ground. Once it leaves the earth, it is no longer part of the earths inertial system. This is basic mechanics. You can consult with any aronautical engineer and verify this. The plane becomes a “free floating” object and is not influenced, cannot be influenced by the rotation of the earth. What is holding the plane to the earths inertial system, gravity? If that were true, a plane could not fly against the rotation of the earth and would be forced, by gravity to follow the rotation. And how would the plane slow down if it was “captured” by the gravity of the earth. It should keep going as long as the earth rotates. If gravity could hold the atmosphere in place and the plane in its inertial system then how could the plane even take off?

        The hot spot is a brighter spot of light that appears on most photos of the earth. This is supposed to be the reflection of the sun. But this cannot be because the sun cannot create a localized bright-spot on the earth. This idea that a reflection of the sun on the earth would show as a brighter spot of light, comes from people that don’t understand physics. Our sun cannot do this because it is 93,000,000 miles away so all of its light rays would be parallel by the time they reach the earth. This means only an even light would shine on the whole earth.

        You can see this when the sun is setting. A long line of light just in front of the sun as it goes over the horizon. Parallel light would not do this. A light source 93,000,000 miles away would not do this. We should see an even glare across the entire horizon and an even reflection of this glare on the surface of the water. This is physics and no amount of words can change that.

        And about the space station. I have seen video of the ISS flying over the earth. You can see the entire space station, where is the camera? There is no ‘selfi-stick’. How is this being filmed?

        I am not a flatty but there are a lot of questions that science just cannot answer or their answers just don’t make sense. There are many of us that are well-educated and can do the science and math ourselves and don’t need to just rely on other people’s word.

        I am encouraged that you seem to be reasonable and want to use facts to prove your point. When I started looking into this, I believed we lived on a globe and never questioned it. That is the problem, never questioning something. They don’t like people qestioning, and we are all encouraged not to question, not to think for ourselves and they use ridicule and insults to stop us from questioning and thinking. I know that when this is the case, when people ridicule and insult you, then people are hiding something and have no facts to back their arguement.

        Just trying to get at the truth with reasons and science. Since the laws of physics cannot be changed, that should be the only criteria for proof. Many people outside the established scientific community can work out the physics as well. And sometimes it just doesn’t work.


  2. To make one point here:

    Planes are still connected to earth’s inertia, as they are fairly low in altitude compared to our atmosphere.

    Space shuttles, however, do gain great benefit from the rotation of the earth, as they are travelling much faster and higher than planes. This is why they always travel east as they go higher and higher.


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