The Constitution of the Atmospheres of the Giant Planets

An analysis is made of the absorption spectra of the major planets: Jupiter, Saturn, Uranus, Neptune. Approximately forty of the rotation-vibration bands are identified as due to absorption by the methane molecule, and are correlated in terms of the fundamental frequencies of vibration. It appears that methane is the major constituent of the atmospheres of these distant bodies, the quantity in the absorbing strata increasing markedly from Saturn to Neptune. The absence of any appreciable amount of other hydrocarbon material is demonstrated.