The reason the sky at sunset is red

Why does the sky turn red at sunset? Because sunset is a symbol of romance? Not so!

Sunset is caused by light scattering in the atmosphere.

Sunset is caused by light scattering in the atmosphere . The Earth's atmosphere contains many small particles, especially nitrogen (78.1%) and oxygen (20.9%).

Sunlight gas (including 7 colors) shines through the atmosphere and will collide with nitrogen and oxygen molecules. Blue and violet light (short wavelengths) are more scattered than red, orange and yellow light (long wavelengths).

During the day, blue and violet light is scattered throughout the sky. Therefore, we see the sky is blue. However, at sunset the sunlight must pass through a longer road in the atmosphere. This means they are scattered by more gas molecules.

As a result, blue and violet light is scattered many times and most of them cannot reach our eyes, only red and orange light is less scattering that can reach the eyes. That's why we see the sunset sky in red.