Observing Earth’s curvature is more difficult when we are too close to Earth’s surface. The highest place within reach of the general public is a commercial passenger flight. Even then, it is still difficult to casually discern the curvature of the Earth from an airplane. With some effort, it is possible to observe the curve of the Earth from a location closer to the surface, as long as we are willing to do some planning and careful observation.
Occasionally, some flat-earthers would ask nicely and demand that the scientific and professional community treat them with respect and take them seriously. They ask everyone to respect them because only with mutual respect, then it would enable everyone to understand and determine the actual shape of the Earth.
Such an attitude is what is expected by the general public. However, respect works both ways. If a flat-Earther starts respecting scientists, professionals & the general public, it would be no longer possible for them to retain their belief in a flat Earth. Unfounded slander to a lot of people comes in a package in the belief of a flat Earth, and can never be separated.
The geoid is the shape that the ocean would take under the influence of the gravity and rotation of Earth alone. The geoid is smooth but irregular because Earth’s density and surface are uneven. ‘Height above sea level’ is measured relative to the geoid.
Some flat-Earthers claim that measuring height above sea level is not possible if the Earth is spherical. They are wrong. Height/altitude/elevation is usually measured relative to the geoid, which is approximately a sphere. The geoid is a more accurate model depicting the shape of the Earth, compared to the spherical & ellipsoid model.
In 1881, Albert A. Michelson performed an experiment in an attempt to prove the existence of aether. Aether was a hypothesized material that fills the region of the universe. Scientists knew light is a form of wave, and because all other waves require a medium to propagate, they formulated the aether hypothesis, in which light can propagate. However, Michelson’s experiment produced a zero effect.
In 1960, Bernard Jaffe wrote Michelson’s biography in the book “Michelson & the Speed of Light.” Unscrupulous flat-Earthers quoted a lone paragraph from the book out of the intended context, and present it as if Michelson proved the Earth is stationary.
Flat-Earthers like to perform the experiment involving lasers to ‘disprove’ Earth’s curvature. If they observe a laser beam from the other side of a lake or an ocean, they would wrongly conclude Earth’s curve does not exist. It was merely a misunderstanding of how lasers work.
The argument from persecution is a fallacy that asserts that if your ideas provoke others to vilify or suppress you, then you must be right. Note: this fallacy is better known as the Galileo gambit. However, in this case, flat-Earthers themselves are the ones defaming Galileo and his ideas.
Flat-Earthers commit the fallacy when they show off that their ideas are being mocked, censored, or deleted. They get such the treatment not because they are right. But because by believing in a flat Earth, they have to accuse a lot of people of being dishonest and part of a global conspiracy.
Leveling is the process of determining the elevation of a point relative to another point. The curvature of the Earth and atmospheric refraction affect the result of leveling. There are techniques and formulas to correct the effect of Earth’s curvature and atmospheric refraction.
Flat-Earthers assume that construction works like roads, bridges, railways, etc. are built without accounting for Earth’s curvature. They are wrong. The leveling in such works are done in such a way it minimizes the errors due to Earth’s curvature and atmospheric refraction.
A ship disappearing from the bottom first is an effect of Earth’s curvature. It is not a direct observation of the curvature itself. We can only directly see the curvature from a significant altitude, not from near the surface.
Flat-Earthers present this reality as if it is a dilemma: 1. Earth is too big for us to see the curvature, but 2. We can see ships go over the curvature. It is a false dilemma. Ships disappearing from the bottom first is an effect of Earth’s curvature. Witnessing such an effect of Earth’s curvature is different from witnessing the curvature itself.
The shape of the Earth can also be determined from the axiological standpoint. If knowledge of a particular shape of the Earth has many applications we use every day, while the other has none, then we can be sure the one with many applications is the correct shape of the Earth.
There is absolutely no technology that depends on the supposed ‘knowledge’ that the Earth is flat. On the other hand, there is plenty of technology we use every day that depend on the understanding that the Earth is a sphere. And therefore, we can be sure that the Earth is a sphere.
An Earth globe is a spherical model of Earth with similar purposes to maps, but unlike maps, do not distort the surface that they portray except to scale it down. The Greeks from the 3rd century BC knew Earth is a sphere, and the earliest globe appeared from that period.
Flat-Earthers take the appearance of a globe before NASA existed as a sign of misconduct, like Universal Studios logo from the 20s. They incorrectly claim that it should not be possible to know Earth is a sphere before the first spaceflight. In reality, we knew spherical Earth since 3rd century BC and globes were already commonplace far before the first spaceflight. In fact, the success of spaceflight depends on our understanding of the spherical shape of the Earth.
Stars are not visible in photos of the Moon –including those taken from the lunar surface— because the Moon is sunlit. The exposure needed to take a photograph of the Moon is not that much different from that used to take a photo in daylight on Earth’s surface.
To demonstrate this, we can try taking a picture of the Moon with stars visible, on the conditions: 1. The lunar features, like the craters, are correctly exposed, not overexposed. 2. Taken in a single exposure, not HDR, and not the result of editing. Even if we are using the best camera available today, the stars can’t show up in large enough quantity.
In September 2015, Buzz Aldrin gave an interview at the National Book Festival in Washington, D.C. Flat-Earthers misrepresented and quoted it out of context as if Buzz was admitting that the Apollo Moon landings never happened.
The original interview was 17 minutes long, and there were other occasions Buzz clearly said the Moon landings happened, without any possibility of misinterpretation.
High-altitude nuclear explosions (HANE) are the results of atomic weapons testing, conducted by the United States and the Soviet Union between 1958 and 1963. In these tests, nuclear warheads were launched and deliberately detonated at a high altitude, between 23 km and 540 km.
Flat-Earthers claim that HANEs were produced by attempts to penetrate the mythical dome enclosing the supposed flat Earth using nuclear weapons. They are wrong. The warheads were deliberately detonated at a high altitude, and the mythical dome does not exist in reality, only in their imaginations.
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.
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.
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.
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.
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.
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.
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.