How is the natural landscape of sunset formed?

Because the earth's surface and atmosphere are curved, the distance of the sun's light passing through the atmosphere near the horizon is much longer than that of the upper layer, so the light entering the bottom layer decays quickly, and the shadow of the earth caused by the sun sinking into the horizon appears blue-gray dark arc in the sky; However, the upper atmosphere has a low density and weak light scattering, which leads to a bright arc on the dark arc.

This wonderful atmospheric optical phenomenon rises to the zenith with the setting of the sun and disappears with the arrival of darkness. As for the beautiful purple light, it is caused by the superposition effect of human eyes, which makes the red light passing through the atmospheric dust overlap with the blue scattered light of the purer air in the upper atmosphere.

Extended data:

These red, orange and yellow lights shine on the clouds, forming a bright and dazzling Xia Hong in the sky. The more water droplets and dust in the atmosphere, the more scattered red light, orange light and yellow light, and the more dazzling the glow.

In the summer morning, if the morning glow is all over the sky, it means that the atmosphere is rich in water vapor. With the increase of temperature and the strengthening of convection, it is possible to form cumulonimbus clouds or cumulonimbus clouds, which is easy to produce thunderstorm weather.

The illusion that the sun is flat appears not only at sunset, but also when the sun jumps out of the horizon. This is because when light passes through the air, the speed slows down by 87 kilometers per second, so the refraction of light changes accordingly. Therefore, when the lower edge of the sunset touches the horizon, the ratio of the height to the width of the sunset is 26.5 ∶ 32 through refraction, and the sun in the eyes of the viewer is naturally flat.

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