Rayleigh scattering

Atmospheric scattering (or diffusion) of light or any other electromagnetic radiation that occurs after striking air molecules or minuscule particles of spherical symmetry in suspension, with diameters less than one tenth of the wavelength of the incident radiation. This scattering is responsible for the blue color of the sky. The intensity of the diffuse radiation emanating from the atmosphere is inversely proportional to the fourth power of the wavelength, as established by the law proposed in 1871 by the British physicist and aristocrat John William Strutt (1842-1919), better known as Lord Rayleigh. If we see the clear sky as blue rather than red or other colors of the visible spectrum, it is because, according to that law, colors of shorter wavelengths (blue and violet) scatter more intensely than those of longer wavelengths (red and orange).