An analemma is a photograph or diagram showing the position of the Sun in the sky, as seen from a fixed location on Earth at the same mean solar time, as that position varies over the course of a year. The diagram will resemble the figure 8.
The north-south component of the analemma results from the change in the Sun’s declination due to the tilt of Earth’s axis of rotation. The east-west component results from the non-uniform rate of change of the Sun’s right ascension, governed by the combined effects of Earth’s axial tilt and orbital eccentricity.
The cruising altitude of a jet airliner is about 33000-42000 ft or 10000-12800 m. It is very tiny compared to the radius of the Earth of 6378 km. Therefore, the distance measured at the cruising altitude does not differ much compared to the surface distance.
Some flat-Earthers claim that if Earth is a sphere, the distance traveled by a jet airliner would have been multiple times the surface distance. They are wrong. The air distance at 33000 ft is only 0.16% farther compared to the surface distance.
A false dichotomy or false dilemma is a logical fallacy which involves presenting two opposing views, options, or outcomes in such a way they seem to be the only possibilities: if one is true, then the other must be false. In reality, there can be many in-between or other alternative options, not just two mutually exclusive ones.
Flat-Earthers like to ‘disprove’ spherical Earth using their own ignorance about various issues. Then they would regard their erroneous belief that spherical Earth has been disproven as “proof” that the Earth is flat. This is fallacious reasoning because the Earth can be in another shape instead.
Defishing is a process for removing barrel distortions in fisheye images. It takes fisheye images, and convert them to normal, rectilinear images that preserve straight lines. Different fisheye lenses can have a different amount of distortions, and thus, require a different defishing strength.
Some flat-Earthers would deliberately use stronger defishing parameters than necessary for the lens being used. Their intention is not to remove the barrel distortion in the resulting images, but also to introduce pincushion distortions to the images. Pincushion distortion is the reverse of barrel distortion. It would curve a straight line to the other direction from what would be produced by the barrel distortion in fisheye lenses. At a specific position in the scene, it would make the curved horizon to appear flat.
During a sunset, mountain peaks lose sunlight later than areas around them. From a viewer observing a mountain, a shadow can appear ascending from the base to the peak. And conversely, during a sunrise, mountain peaks get sunlight before the areas around them and a shadow can appear descending from the peak to the base.
This phenomenon occurs because the Earth is a sphere. As the altitude increases, the hours of daylight become longer. It makes the sun rise earlier and set later.
Albert Einstein used thought experiments as a tool for formulating his theories. His theories provided predictions that can be tested in observation and experiments. He did not perform the observation and experiments himself. Others did and confirmed his theories.
Some flat-Earthers dismiss Einstein’s theories —especially those about gravity— on the basis that they are founded on thought experiments and daydreaming. They are wrong. His theories have been repeatedly confirmed by various experiments and observation performed by many others, even to this day.
A photograph alone is not sufficient to prove that the things or event in the photo is real. The reality of the things or event needs to be determined using inductive reasoning, where multiple information is considered and evaluated together.
Flat-Earthers often claim that we regard certain things or events as real only from photographic evidence. In reality, there is information other than the photographs themselves that was considered and led us to accept the things or events are real beyond any reasonable doubt.
Visual albedo is the measure of the reflection of solar radiation out of the total solar radiation received by an astronomical body, taking into account only the visible light. The visual albedo of the Earth is 0.37, and the Moon’s is 0.12.
The Moon appears darker if the Earth also appears in the same photograph. Flat Earthers use the fact to “prove” that the picture is fake. They are wrong. The Moon appears darker because it reflects less sunlight than the Earth.
In 1851, Léon Foucault used a pendulum to demonstrate the rotation of the Earth. Despite his success, he was not fully satisfied with the pendulum experiment because of the dependency on the sine of latitude, which the public found difficult to understand. He later designed a device which he named ‘gyroscope.’
A spinning gyroscope keeps a constant axis of rotation in space, so it should slowly rotate with respect to an observer attached to the rotating Earth. The challenge was technical; it would need to have minimal friction, and it has to be able to spin for a sufficient duration so that the precession due to Earth’s rotation can be observed.
The fallacy of shifting of the burden of proof is committed when someone makes a claim that requires justification, failed to provide sufficient evidence, but instead demand others to provide the evidence of the opposite of their claim.
Most of the claims from flat-Earthers are bare assertions. They do not provide sufficient evidence. A false way for them to defend their claims is by shifting the burden of proof.
Educating the general public against flat-Earth and other science-related misinformation is more effective by reaching out and using the native language of the intended audience. Currently, our contents are available in three languages: English, Indonesian, and Portuguese; with Arabic will follow soon.
We want to work together with people who are interested in translating our contents into more languages.
A solar filter is utilized to reduce the intensity of sunlight and enable a camera to capture the image of the sun with the correct exposure, even under bright daylight. Without a solar filter, sunlight can be too bright to be correctly exposed by a camera.
Some flat-Earthers made their observation of the sun using a camera without a solar filter. As a result, in some of their images, the sun appears much larger due to the fact the camera cannot distinguish the sun and the sun glare around it.
Muslims perform their prayers by facing the Qibla —or the direction to the Kaaba in Mecca, Saudi Arabia. The direction of the Qibla is traditionally determined from the direction to the Sun when the Sun is directly overhead the Kaaba. If during the time the Sun is visible, it will indicate the direction of the Qibla.
If the results of the observation are drawn on the so-called ‘flat-Earth map’, the Qibla will not consistently point to the Kaaba. Only the calculation using the spherical Earth model will give us consistent results that conform to centuries of observation, from various locations on Earth. The reason is that the Earth is a sphere.
Every magnet has a north pole and a south pole. The opposite poles of the different magnets attract each other, while the same poles of the different magnets repel each other. It is not possible to have a magnet with a single pole.
Flat-Earthers proclaim that Earth cannot be a sphere because if a compass really points to the north pole, then on the equator, it should point 45° downward. They are wrong. A magnet does not only have the north pole, but it also has the south pole which is attracted to the north pole of Earth’s magnetic field. Near the equator, both forces are balanced and pull the compass’ needle to both Earth’s poles at the same time. A perfectly balanced compass will be level near the equator.
The Giza-Orion correlation theory is a fringe hypothesis claiming the correlation between the design of the Giza pyramid complex and the position of Orion’s belt during the time the pyramids were built.
Some flat-Earthers use the Orion correlation theory to prove that stars never change. They are wrong. The theory already accounted for the shift in the position of the stars due to Earth’s axial precession. The theory was formulated using the position of Orion’s belt when Egyptians built the pyramids, not the current position of the stars.
In 2014, scientists discovered an impenetrable barrier in the Van Allen radiation belts. It prevents dangerous ultrarelativistic electrons from getting too close to the Earth.
Some news outlets dubbed it “Star Trek style invisible shield.” Flat-Earthers were too excited reading the headlines and unable to understand the rest of the news. They used it to “prove” the mythical dome above Earth and that spaceflight is impossible. They are wrong. The barrier prevents dangerous ultrarelativistic electrons from reaching Earth. It does not stop us from going to space.
The fallacy of appeal to possibility occurs when a conclusion is assumed not because it has been proven, but because it is possible that it is true, no matter how improbable. Flat-Earthers would often use this fallacious reasoning to prevent their theories from being falsified. In particular, to “disprove” photos and videos taken from space.
The amount of horizon curvature that appears in a photograph of the horizon depends on several factors:
The altitude of the observer.
The field of view of the camera.
Lens distortions of the camera.
Some flat-Earthers assume that we should see the same amount of Earth’s curvature everywhere. And when they see the different amount of curvature in the different picture of Earth’s curvature, they wrongly took it as “proof” of some sort of misconduct.
Because the Earth is a sphere, the surface of Earth obstructs distant enough objects. Climbing to a higher altitude allows us to see farther and more of the previously obstructed objects will become visible, starting from the tops first.
This phenomenon would not occur if the Earth were flat. In a flat Earth, it would not be possible for Earth’s surface to obstruct more of an object —starting from the bottom portions first— if the observer is closer to the surface.
The same thing also happens for objects nearby a large body of water. The surface of the water —which is obviously lower than the object— can obscure the object if the viewer is far enough. Flat-Earthers often invent the “explanation” that Earth’s contour causes the obstruction. This phenomenon can easily prove them wrong.