Shell theorem is a simplification stating that a spherical body affects external objects gravitationally as though all of its mass were concentrated at a point at its center.
The direction of Earth’s gravity toward the center of the Earth made some flat-Earthers to assume that we think gravity is caused by something in the center, and that our inability to go there “disproves” gravity. They are wrong. Earth’s gravity is the result of the entire mass of Earth. Using the center of the Earth is merely a simplification.
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Nikola Tesla was a genuine physicist, engineer, and inventor. He knew very well that the Earth is a rotating sphere, gravity exists, stars are very far, planets are not stars, etc.
Flat-Earthers often claim Nikola Tesla as their own, as if he believed in a flat Earth. These claims are quickly proven wrong by merely reading some of Tesla’s writings. It is obvious from his writings that he was not a flat-Earther.
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Camera zoom works by enlarging the center portion of the image, or in other words, by making its field-of-view narrower. Zooming in on the setting sun will not reveal more of the sun, and will only enlarge the size of the sun in the resulting image.
Flat-Earthers are claiming that zooming in on a setting sun will reveal the entire sun, and somehow lift it out of the water. They are wrong. They simply used the incorrect exposure settings. In reality, zooming on the setting sun will never reveal the sun that is already obstructed by Earth’s curvature.
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Everyone on Earth observes the same face and phase of the Moon at the same time, provided the Moon is visible from the location of the observer. This fact is contrary to what the flat Earth model requires. It rules out the possibility of a flat-Earth and that the Moon is a sphere hovering a few thousand miles above Earth’s surface.
Continue reading “The Appearance of the Moon on the Different Locations on Earth”
The fallacy of ‘appeal to definition’ is using the definition of a term to support an argument as if the term cannot have other meanings or even conflicting meanings. Flat-Earthers often use this fallacy, for example, over the word “theory.”
A communication problem can occur when a term gets misinterpreted to mean other than what was intended. A simple clarification should quickly correct the problem. The appeal to definition arises if the clarification is refused, and the person insists on using the wrong & unintended meaning of the term, and use it to support their arguments.
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A seismometer is an instrument that responds to ground motions, such as caused by earthquakes, volcanic eruptions, and explosions.
Seismometers are sensitive but they cannot detect Earth’s motion. Flat-Earthers use this to ‘prove’ the Earth is stationary. They are wrong. A seismometer is mounted on Earth’s surface and is already moving at the same speed as the surface itself. It can only detect motion if there is a change in speed —or an acceleration— exerting a force to the seismometer.
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Flat-Earthers like to use scale models to represent an actual object. They would apply the facts they observe from the model to the actual object itself. It is the fallacy of false analogy. The two situations can be substantially different. Just because both the scale model and the real object looks the same, it does not mean they are similar in another aspect.
Observation of the real object is stronger evidence than any argument from analogy —like using a scaled-down model of the real object. Using an analogy to dismiss the result of direct observation of the real object is unreasonable.
Continue reading “False Analogy in the Use of Scale Models in Flat-Earth “Experiments””
The Earth retains an atmosphere because gravity pulls air particles toward the center of the Earth. Without something affecting the air —like gravity— air particles would move toward lower pressure, and Earth would lose its atmosphere.
Flat-Earthers claim that Earth should not be able to have an atmosphere because without any barrier separating Earth’s atmosphere and space, it would have been sucked by the vacuum in space. They are wrong. Gravity pulls air and allows Earth to retain an atmosphere.
Continue reading “Vacuum in Space and Earth’s Atmospheric Retention”
News satire is a type of parody presented in a format typical of mainstream journalism. Some satirical news outlets use satirical commentary to comment on actual, real-world news; while others offer wholly fictionalized news stories.
Satirical news outlets have produced some “reports” mocking the flat Earth belief. Unfortunately, some flat-Earthers failed to realize the satirical nature of the “news,” and that the “news” was created to mock them. Because they think it was real news, the “news” spreads in flat-Earth communities as hoaxes.
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A railgun is an experimental weapon that uses electromagnetic force to launch high-velocity projectiles. Some railguns are expected to have a range of more than 200 miles.
Flat-Earthers claim that a railgun round always travels straight. And because it can hit targets beyond 200 miles, they use it as “proof” Earth’s curvature does not exist. They are wrong. In reality, railgun rounds are projectiles. The same law of physics that applies to bullets, arrows, or thrown rocks also applies to them. The rounds are affected by air resistance and Earth’s gravity, and will not travel straight for very long. Railguns are capable of hitting targets obstructed by Earth’s curvature and are not proof that Earth’s curvature does not exist.
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Laser guidance is used by the military to guide a missile toward a target. A laser designator marked a target by pointing a laser beam at it. The signals bounce off the target into the sky, where they are detected by laser-guided munition, which steers itself toward the center of the reflected signal.
A laser-guided missile can be launched toward a target behind Earth’s curvature. Flat-Earthers claim it proves a flat Earth as it would have been impossible for the launcher to point a laser beam at the target. They are wrong. The laser designator does not have to be the launcher itself. It can be another unit closer to the target, such as infantry or an aircraft.
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The fallacy of ad-fidentia is committed when someone attacks the opponent’s self-confidence instead of the argument or the evidence.
Scientific method is an empirical method of acquiring knowledge, which is an iterative, cyclical process through which information is continually revised. Flat-Earthers would often question their opponents if they are 100% sure about their claims. If we admit there is a possibility we are wrong or that our claims might be revised in the future, flat-Earthers will use that to ‘prove’ us wrong.
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Measurement error (also called observational error) is the difference between a measured quantity and its true value. A measurement error is not a mistake. Variability is an inherent part of the results of measurements and the measurement process.
Flat-Earthers often point out at ranges of quantities, errors in measurement results, varying results in different attempts of measurement, as well as highlighting the adjectives ‘about’ and ‘approximately’; then present them as ‘proof’ that science does not know it for certain. They are wrong. Any measurement has an error, and it can never be eliminated.
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Gravity is the attraction between objects with mass. The higher the mass, the greater is the gravitational attraction. Gravity is not the result of the shapes of the objects.
Flat-Earthers like to perform the ball-and-water ‘experiment.’ They spray water to a ball, then observe the water does not stick to the ball the same way the ocean water curves over the surface of the Earth. They would wrongly conclude that “gravity does not exist.” Gravity does not come from the spherical shape of objects, Continue reading “The Ball and Water ‘Experiment’”
Different locations on a comparable latitude can have some similarities. However, the latitude is not the only factor that decides seasonal changes, biodiversity, temperatures, and other conditions. The conditions can be vastly different even on places on the similar latitudes.
Flat-Earthers highlight the differences between locations on a similar latitude to the North and South of the Equator and conclude Earth must be flat. They are wrong. There are factors other than latitude that determine the differences.
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Richard Garriott is a video-game developer and entrepreneur who is also an avid magician. On October 2008, he flew to the ISS on board of a Soyuz rocket as a private astronaut. During his time on the ISS, he performed several magic tricks.
One of his magic tricks involves a hammer that floats and a card that seem to fall down as if it is pulled down by gravity. Flat-Earthers were unaware it was a mere magic trick and wrongly assume it demonstrates things are falling down in the ISS, despite other objects in the scene that float.
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A satellite navigation or satnav system is a system that uses satellites to provide autonomous geo-spatial positioning. Several satellites continuously transmit signals containing their positions and the time when the signal was sent. Receiver units listen to the signals and use the information to calculate their positions.
Flat-Earthers assume that if GPS satellites are used to determine positions, then they should be able to pinpoint the position of a receiver. They are wrong. GPS satellites only transmit signals but never receive signals from the receivers. It is impossible for the satellites to determine the position of a receiver.
Continue reading “How GPS and Other Satellite Navigation System Work”
Red herring is a fallacious argument style in which an irrelevant or false topic is presented in an attempt to divert attention from the original issue, with the intention of ‘winning’ an argument by leading attention away from the original argument and on to another, often unrelated topic.
Flat-Earthers often commit the fallacy of red herring —often repeatedly one after another— because their claims are indefensible. For example, they will try avoiding arguments involving direct observations and derail the discussion to other arguments that rely on statements from third parties. Then, they would discredit the third parties and add them to their list of “collaborators” to “win” the debate.
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When aboard an airplane flying at cruising speed, we will not be able to feel that the plane is, in fact, moving at speed of more than 900 km/h. But if the plane changes its speed, turns or changes its altitude, we can easily feel it.
The same thing happens with the motion of the Earth. Due to Earth’s rotation, the surface of the Earth is moving at 1656 km/h near the equator. We never feel it because the speed is constant, or in other words, the acceleration is zero.
Continue reading “Human Perception of Speed and Acceleration”
Humans are social beings. We depend on each other; not everything we need to do can be done by ourselves. We do not produce every food we eat every day, and the same applies to practically every other aspects of our lives.
We often hear flat-Earthers ask if we have researched by ourselves all the things we claim. If we have not researched it by ourselves but only rely on information from third-party, then —according to them— we should not accept the information. It is merely their way to undermine society, and disconnect us from the rest of society.
Continue reading “Humans Are Social Beings and Science is a Social Process”