Sunglint

Sunglint is a phenomenon that occurs when sunlight reflects off the surface of a water body —like the ocean— at the same angle as an observer is viewing the surface. In the affected area, relatively smooth ocean water becomes a silvery mirror.

In the flat-Earth model, the Sun is assumed to be a ‘local light source.’ They like to use a spotlight or a flashlight as an analogy. They present the sunglint phenomenon as ‘evidence’ of the fact that sunlight is local. They are wrong.

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The Moon in Daytime and the ‘Transparent Moon’ Misconception

Earth’s atmosphere scatters sunlight in every direction. Bluish colors are scattered stronger than reddish tones. As a result, the sky is glowing in bright blue during the day. The phenomenon is called the Rayleigh scattering.

Sometimes the Moon is visible during the day. The bright part of the Moon is bright because it is lit by the sunlight. On the other hand, its dark part does not receive sunlight, and thus barely emit any light. Because of these reasons, the dark part of the Moon is dominated by the blue color of the sky.

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Fraunhofer Lines

Sunlight can be broken into its constituent colors using a prism. The colors are the optical spectrum of the Sun. They are the same colors on rainbows. On careful observation, the spectrum is not perfectly continuous, but it has dark lines scattered over the entire spectrum. It turned out that from the lines, we can tell the composition of the Sun without physically getting there.

Some flat-Earthers think that it is impossible for us to determine the composition of the Sun, as it is impossible for anyone to visit the Sun without getting roasted in the process. They are wrong. The composition of the Sun can be determined from the spectral lines, or more specifically for the Sun: the Fraunhofer lines.

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Shadow on Clouds

Before sunrise or after sunset, the Sun is below the horizon and not directly visible. But the sky and clouds above are illuminated because they are high above, and sunlight can reach them.

If there’s a mountain between the Sun and the clouds, it can cast a shadow on the clouds. The flat-Earth model assumes the Sun is always high above, and thus, this phenomenon cannot possibly occur in a flat-Earth.

The fact that a mountain can cast its shadow on clouds far above it is evidence that the Earth is spherical.

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Sun Glare Makes The Sun Appear Larger

The Sun appears to be in the angular size of about 0.53°, and it is constant throughout the day. But sunlight is very intense and causes glare that surrounds the Sun. Because of the intensity, we are unable to distinguish the Sun from its glare.

During a sunset, sunlight’s intensity is reduced as sunlight traverses the atmosphere at an angle. Because of the reduced intensity, the amount of glare will also be reduced, and the Sun can look as if it is shrinking.

Flat-Earthers often see this phenomenon as ‘evidence’ of a receding Sun during a sunset. They are wrong.

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Atmospheric Refraction

Light waves are not always moving in a straight line. When it passes through a medium of a different refractive index, the waves will deviate. The phenomenon is called refraction and described according to Snell’s Law.

Earth’s atmosphere has variation in air density that depends on the altitude. As the refractive index changes with the density of the medium, light waves passing through Earth’s atmosphere also experience refraction.

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Earthshine Proves the Moon Obscures the Sun During a Total Solar Eclipse

During a total solar eclipse, the Moon is right between the Earth and the Sun. Thus, the near side of the Moon does not receive any sunlight. But while it is dark, it still gets some light reflected by the surface of the Earth. This phenomenon is called Earthshine.

Some flat-Earthers argue that a solar eclipse is not caused by the blocking of the Sun by the Moon, but by another, mysterious celestial body. The reason is that eclipses are incompatible with their beliefs about the motion of the Sun and the Moon.

Earthshine proves that they are wrong.

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