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.
Continue reading “The Curvature Fitting Game”
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.
Continue reading “The Reasons Why Fisheye Lenses Are Used”
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.
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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.
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In many pictures taken from space, stars are not visible, even with a dark sky. The reason is that stars are very dim compared to the primary object in the pictures. If the camera is set to take a correctly exposed image of an object that is much brighter than the stars, then the stars would not be visible in the picture. The same thing would happen everywhere, in space, or on the surface of the Earth.
Flat-Earthers often take the lack of stars as fakery. They are wrong. This is simply a limitation of any camera.
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The Sun appears to be in the angular size of about 0.53°, and it is constant throughout the day. But sunlight is very intense and causes glare that surrounds the Sun. Because of the intensity, we are unable to distinguish the Sun from its glare.
During a sunset, sunlight’s intensity is reduced as sunlight traverses the atmosphere at an angle. Because of the reduced intensity, the amount of glare will also be reduced, and the Sun can look as if it is shrinking.
Flat-Earthers often see this phenomenon as ‘evidence’ of a receding Sun during a sunset. They are wrong.
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Zooming in using a camera merely magnifies the center portion of the image. Changing zoom does not change an object’s position with respect to another object or the camera. It will not reveal more of a distant object.
Flat-Earthers often claim that zooming in will reveal distant objects that are ‘allegedly’ behind the curvature. They are wrong. If the object is really behind the curvature, then no amount of zooming can bring the object back into view.
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Soundly’s pictures and videos of Lake Pontchartrain power lines and causeway really stirred up flat-Earthers’ nests. They clearly show the curvature of the Earth, where it is usually hard to discern. For the rest of us, those pictures are simply the consequence of the fact that the Earth is a globe.
But obviously, flat-Earthers can’t take this, and they invented various excuses to attack the credibility of these pictures and videos. Some of them look for specific vantage point where it is impossible or very hard to discern the curvature. They would conclude if the curvature can’t be seen from these viewpoints, then it should not be visible from Soundly’s viewpoints.
Continue reading “Perspective Compression: a Perspective Aid to Determine If a Curvature Exists”
High-altitude balloon footage is often abused by flat-Earthers to show us that the Earth is flat when seen from a high altitude.
We analyzed more than two dozens of footage taken from high-altitude balloons on YouTube, and we can easily conclude the curvature is there and usually easy to spot, including in the cases where flat-Earthers use the video as ‘proof’ of a flat Earth.
Continue reading “Curvature of the Horizon in High-Altitude Balloon Footage”
Sometimes, we can see clouds appearing as if they are behind the Sun or the Moon. Obviously, this is simply an illusion. But some flat-Earthers regard this as ‘evidence’ that the Sun and the Moon are close, closer than clouds ‘above’ them. They are wrong.
Continue reading “The Illusion of Clouds Appearing ‘Behind’ the Sun or the Moon”