REMOTE-SENSING OF THE ATMOSPHERES OF JUPITER, SATURN AND TITAN

Knowledge of the atmospheres of Jupiter, Saturn and Titan has made huge progress thanks to the remote sensing exploration by the Voyager spacecraft, considerable information has also been obtained by ground-based infrared spectroscopy. Jupiter and Saturn have a hydrogen-rich atmosphere with trace constituents in a reduced form. From the determination of elemental and isotopic ratios, one can derive information about their formation and probable evolution. Titan, Saturn's largest satellite, is a unique object in the Solar System. Its nitrogen-rich atmosphere and its surface pressure show some conditions similar to the Earth's atmosphere; the discovery by Voyager 1 of complex molecules (hydrocarbons and nitriles), produced by the dissociation of methane and nitrogen, suggests the possible development of a complex carbon chemistry.