Light Scattering Demonstration Using Laser Pointers

Flat-Earthers cannot understand why space appears dark if the Sun is in space, and they use their ignorance to discredit science.

In reality, sunlight does travel through space. However, space is a vacuum, and there is nothing to scatter and redirect the light toward our eyes like in Earth’s atmosphere. We can demonstrate the phenomenon using a low-powered red and green laser pointer in clean air.

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Visibility of Objects in Space Compared to Those on Earth’s Surface

Visibility is a measure of the distance at which an object can be clearly discerned. Visibility depends on the transparency of the air. There is no air in space to disrupt the transmission of light, and therefore, light can travel very far in space practically undisturbed.

The ISS can be seen clearer than objects on Earth’s surface far closer than the ISS. Flat-Earthers use the fact as “evidence” that the ISS is much closer. In reality, only a fraction of the light path from the ISS travels through the dense lower part of the atmosphere that will significantly affect the transmission of light.

On the other hand, light emitted by objects on Earth’s surface has to travel the entire path through Earth’s atmosphere.

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Hovering Helicopter and Earth’s Rotation

Because of inertia, we cannot travel to another location by hovering inside a helicopter and waiting for the Earth to rotate below us until we are above our destination.

Flat-Earthers claim that we cannot do such a thing as ‘proof’ of a motionless Earth. In reality, when still on the ground, the helicopter is already moving at the same velocity as Earth’s surface.

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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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Blood Moon: Why The Moon Turns Red During a Total Lunar Eclipse

The Moon becomes red during a total lunar eclipse because Earth’s atmosphere acts like a lens and refracts sunlight toward the Moon. It also scatters bluish components of sunlight more strongly and lets more reddish components reach the Moon.

The Moon does not become totally dark during a total lunar eclipse, and flat-Earthers use it as “evidence” the Moon is not in Earth’s shadow during a lunar eclipse. In reality, it occurs due to optical phenomena involving Earth’s atmosphere.

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Experiments Involving Flashlights, Laser, & Reflected Sunlight Over Water Surface

Atmospheric refraction is stronger near the surface. Additionally, a thermal inversion can form a duct guiding light ray to follow the curvature of Earth. These phenomena allow light rays to reach the viewer far behind the horizon, but the rays will be compressed, distorted, and scattered, and will not form the true image of the objects. However, a nondescript, intense point light source will stand out against a darker background.

Flat-Earthers like to perform experiments involving lasers, flashlights, and mirrors over the water surface. If the light is visible from the other side, they would wrongly conclude Earth’s curvature does not exist. In reality, atmospheric refraction causes the result they observed.

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Moving Vehicle Analogy: Inside vs Outside of the Vehicle

The moving vehicle analogy is often presented to explain how Earth’s rotation does not seem to affect an object’s motion. Similarly, a ball released inside a moving vehicle will not fall rearward because it retains its inertia.

Flat-Earthers offer the moving open-air vehicle as if it is the “correct ” analogy. In reality, with their analogy, the air moves relative to the vehicle, which exerts an additional force that does not exist in the fact being explained. Their analogy fails to represent the fact being explained.

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Airplanes and Earth’s Rotation

An airplane exists on Earth. It has the same motion as the surface of the Earth, including Earth’s rotating motion. The motion and speed of an airplane are measured relative to Earth’s surface.

Flat-Earthers claim that an airplane should not be able to fly eastward or land. In reality, an airplane is moving relative to the surface. It has Earth’s motion as a component of its motion and does not need to chase Earth’s rotation.

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Pressure Difference Without a Barrier

Atmospheric pressure decreases as altitude increases. A pressure difference can occur without a barrier. Other factors, like gravity, can cause a pressure difference.

Flat-Earthers claim a pressure difference cannot possibly occur without a barrier, like Earth’s atmosphere next to the vacuum of space. In reality, it is not difficult to demonstrate that a pressure difference can exist without a barrier.

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Selenelion: The Phenomenon Where Both the Sun and Moon Are Visible During a Total Lunar Eclipse

A selenelion occurs during a lunar eclipse when the sun and moon are observed above the horizon. Atmospheric refraction bends light rays and lifts the image of the sun, and the moon typically up to 0.6°, so both can appear above the horizon.

Flat-Earthers assert that a selenelion should not be possible if Earth is a sphere due to the fact during a lunar eclipse, the sun and moon are 180° apart. In reality, a selenelion is possible because Earth’s atmosphere refracts light.

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Visibility Range vs Angular Resolution

Visibility range is a measure of the distance at which an object can be clearly discerned. Angular resolution is the ability of an optical system to resolve detail in the object.

Unlike the claim from flat-Earthers, there is no such thing as the “maximum range” of a camera. A germ on our hand is well within the visibility range, yet a regular camera lacks sufficient angular resolution to see it. On the other hand, an airplane is much farther away, but it has a larger angular size and can be seen by the camera.

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Inferior Mirage

An inferior mirage is a phenomenon in which atmospheric refraction bends light rays to produce a mirrored image below a real object. It occurs when a hot surface heats the layer of air above it, placing it below a colder & denser layer of air.

Flat-Earthers like to use inferior mirages to “explain” how a distant object can appear partly obstructed if the Earth is flat. In reality, an inferior mirage cannot produce an appearance similar to an object partially obscured by Earth’s curvature.

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Geocorona

In 2019, scientists discovered that Earth’s atmosphere consists of a hydrogen cloud called the geocorona that extends to the Moon and beyond. Its density is minuscule, practically vacuum, and does not affect space travel.

Flat-Earthers claim this is an “admission” as the Moon has always been “inside the dome” in their flat Earth model. In reality, the discovery does not change much about what we already know.

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Refraction: Only a Baseless Technobabble in Flat Earth Community

Flat-Earthers use the phenomenon of refraction as a catch-all “explanation” every time they observe something not appearing in the expected position if the Earth is flat. They use the term “refraction” as mere technobabble without any underlying explanation.

The following are how we can distinguish real-world, scientific refraction from the technobabble used by flat-Earthers:

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Earth’s Shadow and the Belt of Venus

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Earth’s shadow is the shadow that Earth casts into its atmosphere, toward the opposite point from the sun. Above Earth’s shadow is the Belt of Venus, a pink band from the scattering of sunlight through the atmosphere.

Earth’s shadow lies at the antisolar point —the point opposite the sun. It rises when the sun sets and sets when the sun rises. The phenomenon shows us that the sun really goes below the horizon and disproves the flat Earth model.

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Atmospheric Pressure and the Vacuum in Space

Atmospheric pressure decreases as altitude increases. There is no visible boundary between Earth’s atmosphere and space in terms of pressure. There is no abrupt drop in pressure where space begins.

Flat-Earthers assert that it is impossible for the pressurized atmosphere to meet the vacuum of space without any barrier. In reality, the pressure changes gradually. There is no sudden pressure drop between the atmosphere and space.

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Temperature Differences Between the Equatorial & Polar Areas

Polar areas have a lower temperature than areas closer to the equator because the same amount of solar radiation is dispersed over a larger area, and the surface of ice and snow reflects more sunlight than darker surfaces.

In the spherical Earth model, the distance to the Sun from the poles and the equator is practically the same because the sun is much farther than the distance between any two locations on Earth. Because of that reason, flat-Earthers then claim that the temperature in polar and equatorial areas should be the same. In reality, the distance to the sun is not the only factor that can determine temperature.

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Moving Vehicle Analogy and the Physical Barrier Excuse

We cannot feel the Earth rotating, and to explain the phenomenon, we usually use the moving vehicle analogy. If the vehicle is moving at a constant speed, we will not be able to sense the motion. We cannot feel the motion of Earth because of the same reason.

Flat-Earthers invented the excuse that we are standing on Earth, not inside it, to falsely reject the explanation.

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Zooming In On Distant Boats Does Not Disprove Earth’s Curvature

If a distant boat is not visible, then it is because of at least one of these reasons:

  • Our eyes have limited angular resolution and are unable to resolve the ship at that distance.
  • The atmospheric condition is limiting our visibility.
  • The curvature of the Earth obscures the ship.

Flat-Earthers like to demonstrate that a previously invisible ship at a distance can be made visible by zooming in. They would use it to disprove Earth’s curvature. They are wrong. There are reasons other than Earth’s curvature that can obscure a distant boat.

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Vacuum in Space and Earth’s Atmospheric Retention

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.

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