Rayleigh Scattering
Résumé
Rayleigh scattering is an exact, analytical solution to the problem of radiation scattering in the limit of a vanishingly small scattering particle compared to the radiation wavelength. As such, it is valid for gaseous molecules at wavelengths used in planetary atmospheric studies, resulting in a polarized, conservative scattering increasing toward shorter wavelengths. It gives a characteristic bluish hue to the upper layers of clear atmospheres, has a major influence on planetary albedos (and thus radiative balance), and provides a lower bound on the probed altitude for transit spectroscopy.