Earth’s curvature is hard to observe from the surface. Even from the altitude of a commercial passenger flight, about 30000-40000 ft, Earth’s curvature is still too small to notice. However, under careful observation, it is not impossible to confirm the curve from the cruising altitude of a jet airliner.
A large amount of flat Earth memes present an image taken from a high-altitude balloon, showing the appearance of a flat horizon. Such images evidently cannot be regarded as “proof” of a flat Earth. The horizon appears flat only because of the barrel distortion from the fisheye lens.
The following is how any unscrupulous flat-Earther try to deceive us using footages from high-altitude balloons.
A panorama image is stitched from multiple photos that were taken from different angles, forming a very wide field of view, even 360°×180°, covering every possible angle from the viewer.
Someone has taken a panorama from a high-altitude balloon and made available the results in various projections. Flat-Earthers saw a flat horizon in one of the panorama images and took the wrong conclusion. The horizon will appear flat in a cylindrical or equirectangular projection due to an effect of the projection. The panorama creator also has the panorama in other formats, including an interactive one in the general perspective projection, which shows how it would look from a human eye, and it shows the curvature.
The Tycho Crater is a crater on the Moon having the diameter of 85 km (53 miles). It is too small to recognize using the naked eye. However, it lies on a bright colored highland that can be mistaken as the crater itself. The crater also has an extensive ray system, which was from the ejected materials when the crater was formed.
Flat-Earthers claimed the visibility of the Tycho Crater proves the Moon is not that far. They are wrong. We cannot see the Tycho Crater using the naked eye. What is visible is the highland it lies on or its extensive ray system.
NASA has published several pictures of the Earth that are composites. It means the pictures were the result of combining many images into a single picture. In most cases, the source pictures were taken from low-orbiting satellites to obtain higher resolution pictures of the Earth.
Flat-Earthers discovered the photos are composites and claimed to have exposed “yet another evidence” of wrongdoing. They would publish this “findings” everywhere to turn us emotional. They are wrong. Nobody is covering the fact the pictures are composites, and there is no intention to deceive. Information that the photos are composites can be readily found in NASA’s website, far before the claimed “discovery” by flat-Earthers.
Generally, sunlit objects are far brighter than any stars. It is the reason stars are not visible in a lot of photographs showing sunlit objects unless the objects are overexposed and made much brighter than the correct exposure.
Flat-Earthers take the lack of stars in photographs as evidence of misconduct. They are wrong. If the primary object in the picture is sunlit, then in most cases, stars will not be visible.
In photography, exposure is the amount of light reaching the camera film or sensor, as determined by shutter speed, lens aperture, and scene luminance. By adjusting the exposure and sensor/film sensitivity (ISO), it is possible to get a bright or dark result.
It is quite apparent that photography has never been any flat-Earthers’ strongest point. There are many misconceptions in flat-Earth circles that arise from their ignorance about photography. One of such misconceptions is exposure.
The amount of Earth’s surface we can see at once from a location in space depends on our distance to the Earth. The closer the observer, the smaller the amount of visible Earth’s surface. Conversely, the farther the observer, the larger the amount of Earth’s surface visible to them. But no matter how far the observer, they would not be able to see the entire hemisphere.
Flat-Earthers discovered that there are the differences in the sizes of continents in the different images of the Earth, and used the fact as ‘evidence’ of misconduct. They are wrong. Such differences in continent sizes are present because the images show the Earth from different distances and different field of view.
In some photographs of the Moon, there are bright spots in the dark part of the Moon. Some flat-earthers believe that these are ‘stars’, and the Moon is actually transparent.
These are in fact image noise, not stars.
The surface of the Earth close to the equator is moving at the speed of about 1670 km/h due to Earth’s rotation. To take a sharp picture of the Earth with the resolution of 10000×10000 from a stationary position in space, it would require the shutter speed faster than 2.7 seconds. It is not difficult at all to take a sharp picture of the entire Earth without perceivable motion blur.
Flat-Earthers claim that it should be impossible to take a sharp picture of the Earth from space due to the speed of Earth’s rotation. To them, the fact that a photographer cannot take a sharp photo of a speeding race car from the sidelines (they actually can) tells us it should be impossible to take a sharp picture of the Earth moving at 10× the speed.
They are wrong. Motion blur is caused by the angular speed of the object relative to the camera, not from its absolute speed. The vast distance required to take a photo of the Earth results in a very low angular speed, making it not difficult at all to take sharp images of the Earth.
If we were to magnify the surface of any spherical object with large enough magnification, then at some point, it would appear flat. This can be easily demonstrated using a macro lens as the Redditor ‘Useless-Pickles’ did. He magnified the surface of a basketball using an extreme macro lens as a philosophical demonstration.
This shows that the surface of a spherical object can easily look flat if the object is large enough, or the observer is small enough. And the basis of all flat-Earthers’ belief that the horizon appears flat is insufficient to determine the shape of the Earth. By applying the same “logic” as these flat-Earthers, we can actually “prove” a basketball is flat, which, as we all know, is clearly wrong.
A photograph of an object does not necessarily look the same as the real object. There are various optical imperfections, which are impossible to avoid by both the designer of the optical system and the photographer taking the picture. One of those imperfections causes lens flare.
Some flat-Earthers noticed the existence of a ‘mysterious celestial body’ next to a photograph of the Sun or the Moon. They would use such sightings to ‘explain’ various celestial phenomena which cannot be readily explained in the flat Earth model, like eclipses. They are wrong. The ‘mysterious celestial body’ was merely a lens flare.
The first photo showing the entire Earth was taken in 1966 from the spacecraft Lunar Orbiter 1. Since then, there are too many photos showing the whole earth taken from various missions to space.
The advent of computers in the 80s introduced a new technique of generating such pictures. A satellite can be used to take many photos of the Earth from a low orbit, and computers can be used to assemble those pictures into a single photo of the Earth.
Flat-Earthers ‘discovered’ such technique, then they concluded that all pictures of the Earth taken from space are all composites, the results of manipulation or assembled by computers. They are wrong. Just because there were pictures created using such technique, it doesn’t mean there is no genuine picture showing the entire Earth, not composites, not stitched, and were taken from a single shot.
When we are unable to see a distant object, then it is due to one of these reasons:
- Our eyes lack the sufficient angular resolution to recognize the object.
- Atmospheric condition limits visibility.
- The object is far enough and obscured by Earth’s curvature.
Some flat-Earthers like to show that a previously unseen distant object can be brought into view using infrared vision. They would take that as ‘evidence’ of the non-existence of Earth’s curvature. They are wrong. Infrared vision can reveal hidden objects caused by visibility limitations, but not ones obscured by Earth’s curvature.
Flat-Earthers reject the existence of satellites. They are wrong. To prove the existence satellites, we can attempt to take pictures of the ISS when an ISS transit happens, or the ISS passes in front of the Sun or the Moon.
There are videos showing the sun to appear to set, but after the camera is zoomed in, the sun is still above the horizon. The reason is that the camera’s autoexposure system is constantly adjusting the exposure, and in such scenes, there’s a difference in overall brightness before and after zooming in.
Flat-Earthers are taking such videos as ‘evidence’ of a receding sun. They are wrong. This is merely a matter of photography. In reality, the sun is not receding, and it has the same angular size throughout the day.
The amount of curvature that appears in a photograph of a sphere depends on 1. The radius of the sphere, 2. Camera distance from the sphere, 3. Field of view of the camera, and 4. The distortion characteristic of the camera being used.
The ‘curvature fitting game’ has been flat-Earthers’ favorite pastime. They would try to fit a photograph of Earth’s curvature with another. If they find the result is not proportionally correct, they will make fun of it. They are wrong. Two different photos of a sphere can be taken differently and would show a different curve, even if the object being photographed is the same object.
Action cameras are being used in high-altitude balloons, rocket launches, and the ISS because they have some advantages compared to other cameras. And most action cameras are equipped with a fisheye lens.
Flat-Earthers allege that there is an evil intention behind every use of fisheye lenses, especially in space and high-altitude usages. They are wrong. The use of fisheye lenses is not unreasonable. And if a rectilinear result is desired, it is trivial to convert any fisheye footage to a rectilinear one.
Polaris is a bright star that is close to the north celestial pole. Currently, Polaris is only 0.74° apart from the north celestial pole and the only star visible to the naked eye that is close to the celestial pole. This is why Polaris is popular as a navigational aid in the northern hemisphere.
Some flat-Earthers think that Polaris is stationary and that it is a ‘special star’ because other stars are in motion around it. They would take that as ‘evidence’ that the Earth is motionless. They are wrong. Polaris is merely a regular star, just like the others.
A fisheye lens distorts images. It results in images having barrel distortions. In a fisheye lens, a straight line can appear curved. But some flat-Earthers don’t realize that the opposite is also true, a fisheye lens can easily make a curved line look straight.