Rayleigh Scattering
Rayleigh scattering was named after the 19th-century British physicist Lord Rayleigh. It is the predominantly elastic scattering of light or other electromagnetic radiation by particles much tinier than the wavelength of the radiation. Rayleigh scattering on sunlight in the Earth's atmosphere causes diffuse sky radiation, which is the reason for the blue color of the sky, as well as the reddish hue of the low sun.