What makes the sun turn red at sunset?

One of the most beautiful moments of the day is the sunset. As the Sun approaches the horizon, it begins to change color, taking on red, orange and yellow hues. But why does this happen? Why does the sun turn red during sunset? In fact, the Sun does not change color, but it seems to do so because of the sun’s rays that spread into the Earth’s atmosphere. Our star emits light in various frequencies, the white light, which is the sum of all the colors of the visible spectrum. As the sun's light reaches the Earth's atmosphere, it interacts with the particles of gas and dust in the air. Gas particles in the atmosphere, such as nitrogen and oxygen, diffuse blue light more than other colors. This means that the Sun's blue rays propagate through the atmosphere and disperse in all directions, making the sky blue during the day.

However, when the Sun is low on the horizon during sunset, the sun’s rays must cross a greater amount of the atmosphere to reach the observer. In this way, most of the blue rays are dispersed in the atmosphere, leaving the red and orange rays to prevail. Dust particles and air pollutants can also increase the effect of sun rays. During sunsets where the air is particularly polluted, the colors may appear even more intense. In short, the sun does not turn red at sunset, but seems to be because of the selective diffusion of the sun's rays into the Earth's atmosphere. The phenomenon is most evident during sunsets when the air is clean and free of pollutants. For this reason, watching a sunset with a red, orange and yellow sky can be an amazing and always different show, capable of surprising and exciting every time.