Question

The evening sunsets are reddish orange because the atmosphere?

1) is most efficient at scattering red light.
2) absorbs blue light.
3) is more efficient at scattering blue light.
4) absorbs the red light.
5) contains small amounts of red dust that give the air its red color.

Answer 1

Evening sunsets are reddish-orange due to Rayleigh scattering in the Earth's atmosphere, which scatters shorter blue wavelengths more efficiently than the longer red wavelengths. The Sun's light when low on the horizon travels through more atmosphere, reducing the intensity of blue light reaching the observer, thus emphasizing the red light.

Step-by-step explanation:

The reason the evening sunsets appear reddish-orange is due to the scattering of sunlight by the Earth's atmosphere. When the Sun is low in the sky, its light has to travel through a thicker layer of the atmosphere, which increases the chances of the light being scattered. The scattering process, as dictated by Rayleigh scattering, is more efficient for shorter wavelengths such as blue and violet, which are scattered out of the direct path of the light before it reaches our eyes. Therefore, the longer wavelengths like red and orange are less scattered and become more pronounced in the direct sunlight that reaches an observer at sunset.

This phenomenon is also what causes the sky to appear blue during the day, as the shorter, bluish wavelengths are scattered in all directions, filling the sky with blue light. This scattering effect is less pronounced for red light, resulting in a yellowish appearance of the Sun when it is high in the sky, which shifts to redder tones during sunrise and sunset. It's important to note that the reddening effect we observe is not due to red dust in the atmosphere; rather, it is a consequence of the differential scattering of different colors by the molecules and small particles in the atmosphere.