Why are dawn and sunset skies often red?
The explanation for the reddish tints seen in the sky at either end of the day also lies in Rayleigh scattering. As it passes through layers in the atmosphere, light with shorter wavelengths is scattered more than light with longer wavelengths. For this reason, blue light, with its short wavelength, is scattered more than red light. When the Sun is high in the sky, and the journey that sunlight takes through the atmosphere is relatively short, blue is predominantly scattered and the result is a blue sky. When the sun is low, the light travels much further through the atmosphere and scattering reduces the blue content to such a degree that red predominates. Blue is literally scattered away. This is why the sky is red at sunrise and sunset. Sunlit clouds and droplets of water in the air further intensify the red tint. How are the colours in a rainbow formed? The ideal conditions for a rainbow occur when a brief morning or evening shower is followed by a rapidly brightening sky. Large num
