infrared radiation of the giant planets

The study of the giant planets is of major interest for cosmogonical and cosmological research, because their atmospheres are, in some aspects, representative of the early stage of the solar system. From the study of the planetary spectra in the near-infrared and far-infrared range, many important results have been obtained during the past 10 years, especially about the abundance ratios of elemental and isotopic species, and some physical and chemical parameters of the planetary atmospheres. These results are reviewed and discussed in detail. In particular, it is concluded that the Jovian atmosphere does not seem to have significantly evolved since its origin. (author)