Air Density vs Object’s Weight

At a lower altitude, the air is denser, and objects weigh more. On the other hand, at a higher altitude, the air is less dense, and objects weigh less.

Flat-Earthers deny gravity and invented the “explanation” that an object falls only because it is denser than the air surrounding it. But if it were true, objects should weigh more at a higher altitude where the air is less dense. But they weigh less instead, disproving flat-Earthers’ density theory.

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Allais Effect

The Allais effect is the alleged anomaly of pendulums or gravimeters, which is purportedly observed during a solar eclipse. The effect has not been able to be consistently measured and was most likely caused by experimental error.

Flat-Earthers use the Allais effect to dismiss the result of Foucault’s pendulum. In reality, the Allais effect is still not conclusive. Even if it is true, it only occurs during an eclipse and does not rule out that the pendulum’s precession is due to Earth’s rotation. Not to mention that there is plenty of other evidence that Earth is in motion.

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Implicit Attitude

Implicit attitudes are unconscious influences such as past knowledge, perception, or memory that influence a person’s attitude, even though they have no conscious awareness of the influences.

Many flat-Earthers —especially new ones— seem to be unaware that by believing flat Earth, they are implicitly accusing others of malice & wrongly consider it just another harmless belief. They can be made aware by telling them it is impossible to believe flat Earth without accusing many common people around us —like scientists, pilots, surveyors, etc.— of conspiring. But once aware, it is often still difficult for them to get rid of the influence.

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Center of the Azimuthal Equidistant Map Projection

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Flat-Earthers copied the shape of the azimuthal equidistant map centered on the North Pole and claim it as their “flat-Earth map.” The real azimuthal equidistant map is not the so-called “flat-Earth map, and not necessarily centered on the North Pole.

On the azimuthal equidistant map, all points on the map are at proportionally correct distances from the center point, but only from the center point. Other distances are distorted.

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Curved Airplane Window and Observation of Earth’s Curvature

With careful planning, we can easily observe Earth’s curvature from an airliner. To “explain” the observation, flat-Earthers invented the excuse that it is caused by the distortion from the shape of the airplane’s window.

In reality, all camera lenses are curved, too, yet most of these lenses produce normal, rectilinear images. The fact that the shape of the window is curved does not mean looking through the window will produce a curved horizon.

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Visual Albedo of the Moon and the Earth

Visual albedo is the measure of the reflection of sunlight 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 dark if the Earth also appears in the same photograph. Flat Earthers use the fact to dismiss such photos as fake. In reality, the Moon’s brightness in a photo is just a matter of choosing the correct camera exposure. But if Earth is also present, increasing the exposure will make the Earth appear too bright.

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Just Asking Questions / JAQing-Off

Just asking questions is influencing the audience by framing the assertions as questions rather than statements.

Just asking questions is a common flat-Earthers’ ploy. These are not questions being asked out of genuine curiosity but statements disguised as questions. They are not seeking the answers and expect nobody will be able to answer them. If someone can give the answers to the questions, they will not appreciate it.

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Glare

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Glare can appear around light sources, causing them to appear larger in a photo. The higher the exposure value of the camera, the larger the glare will appear on the resulting photo.

Much flat-Earth misinformation arises from misunderstandings about photography, such as about glare and how to eliminate glare by changing the exposure or by using a solar filter. Using the exposure setting for everyday scenes to capture a photograph of the sun will give us a glare around the Sun. To take a photo of the actual size of the Sun, we need to reduce the exposure, either by changing the in-camera exposure settings or by using a solar filter.

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Images of Full Moon During Sunset

A full moon can only occur if the Sun is directly opposite the Moon in the sky, and it will never appear near the Sun. There are photos on the Internet showing a full moon next to the Sun. These photos are fakes, and the phenomenon cannot possibly occur in the real world.

Flat-Earthers discovered images on the Internet showing a full moon next to the Sun, and they use it as “evidence” that moonlight is not reflected sunlight. In reality, these people are not aware that these photos are obvious fakes.

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Frame of Reference

A frame of reference consists of an abstract coordinate system and physical reference points that uniquely fix the coordinate system and standardize measurements. Speed or velocity is relative to a specific frame of reference. It is possible that two speeds/velocities are measured relative to a different frame of reference and thus cannot be directly compared.

Flat-Earthers like to compare two different speed measurements like an airplane moving at 900 km/h (560 mph) and Earth’s surface near the equator at 1674 km/h (1040 mph). They would conclude the airplane should not be able to catch up with Earth’s surface and would not land if the Earth is rotating. In reality, both the speeds are measured relative to a different frame of reference, and therefore, cannot be compared directly.

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Fake Moon Rock That Turns Out to Be a Petrified Wood

The Apollo missions brought back moon rocks to Earth. Some of the moon rocks Apollo 11 and Apollo 17 brought back were gifted twice by President Nixon to 135 countries. In the Netherlands, both of these gifts are intact and preserved in a museum. However, there is another unrelated gift, in the form of petrified wood that was mistaken to be a moon rock for several years.

Flat-Earthers use the petrified wood incident to discredit the Apollo missions. In reality, the incident is not related to the two moon rocks that the United States officially gifted to the Netherlands, which are still displayed in Museum Boerhaave, Leiden.

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Georgia Guidestones

The Georgia Guidestones is a granite monument in Georgia, United States. In one of the stones, a hole is drilled through that points to the north celestial pole. And consequently, by looking through the hole, the star Polaris is visible at night.

Polaris is visible through the Georgia Guidestones’ hole every night, and flat-Earthers use the fact as “evidence” that Earth is stationary. In reality, due to Earth’s axial precession, in a few hundred years, Polaris will have moved far enough away from the north celestial pole and will no longer be visible through the hole.

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False Balance

False balance is a bias in which journalists present an issue as more balanced between opposing viewpoints than the evidence supports. False balance spreads misinformation because it gives the impression as if the two sides are worthy of consideration.

Flat-Earthers often complain that the media does not give them equal treatment as they do to scientists. In reality, presenting proponents of pseudoscience as being on equal footing misrepresent the reality of the situation and will only spread misinformation.

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Lamp Illuminating a Dark Wall Demonstration

Flat-Earthers often show us images of a lamp illuminating a dark wall to demonstrate —incorrectly— how night can happen on a flat Earth.

In the images, the areas farther from the lamp appear dark. Due to the inverse-square law, areas farther than the source of light receive less light. However, these areas still receive light nonetheless. From these dark areas, the lamp is still visible. This contrasts with what happens at night, that sunlight is nonexistent and the sun is not visible.

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Lunar Transit Images from DSCOVR-EPIC

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DSCOVR is a spacecraft positioned in the Lagrangian point L1 between the Sun and Earth. It carries the EPIC camera that continuously takes images of Earth in 10 wavelengths from 317nm to 780 nm in rotation.

The Moon can appear in EPIC images, and flat-Earthers incorrectly use the color fringing around the Moon to dismiss the images as fake. In reality, the full-color images are composite of three single-color images taken in consecutive exposures in a one-minute span. As a result, the Moon had shifted in the time span and not perfectly aligned in the different exposures, causing the color-fringing after the images are composited together.

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Far-Fetched Hypothesis

Far-fetched hypothesis is a logical fallacy that occurs when someone offers a bizarre and far-fetched hypothesis as the correct explanation without ruling out more mundane explanations.

Every time flat-Earthers “discover” a natural phenomenon that they feel “strange,” they will act as if they are the first humans to know about it and then try to find ways to use it as “evidence” of flat-Earth. In reality, it is far more plausible that other people already know the phenomenon and its scientific explanation, and these flat-Earthers are just unaware of it.

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Perspective of Earth Due to Different Observer Distance

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Because of a perspective effect, an observer in space can see more of Earth’s surface if they are farther from Earth.

Flat-Earthers noticed the different visible Earth’s surface in different Earth images and used it to “prove” they are fake. In reality, it is just a perspective effect caused by the fact that the Earth was seen from a different observer distance.

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Five Photos of Neil Armstrong on the Moon

Neil Armstrong was the lead photographer on the Apollo 11 mission, and he could not be in the photos he was taking. Out of 1266 photos from the Apollo 11 mission, only five good photos of Neil were taken while Apollo 11 operated on the surface of the Moon.

Some memes humorously compare the total of five photos of Neil on the Moon to the number of selfies some ladies take in the bathroom. Flat-Earthers took them too seriously, and these became a hoax claiming that Apollo 11 brought back only five photos.

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Gravitational Acceleration in Archimedes’ Formula

Archimedes’ principle states that the upward buoyant force exerted on a body immersed in a fluid is equal to the weight of the fluid that the body displaces. Today we usually use B =  -ρgV to calculate the buoyant force, where ρ is the fluid’s density, g is the gravitational acceleration, and V is the volume of the displaced fluid.

Archimedes discovered buoyancy earlier than Newton discovered gravity, and flat-Earthers dispute the presence of g in the buoyancy formula. In reality, buoyancy depends on the weight of the fluid, and the distinction between weight and mass only occurred after Newton. Archimedes’ principle still applies, only that we now have a better understanding of what weight is.

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