Solar System and neon, which were always in the gaseous phase in the nebula. Ices, like water, methane, ammonia, hydrogen sulfide, and carbon dioxide, have melting points up to a few hundred kelvins. They can be found as ices, liquids, or gases in various places in the Solar System, whereas in the nebula they were either in the solid or gaseous phase. Icy substances comprise the majority of the satellites of the giant planets, as well as most of Uranus and Neptune (the so-called "ice giants") and the numerous small objects that lie beyond Neptune's orbit. Together, gases and ices are referred
Sudarsky's gas giant classification their modeled physical atmospheric properties. In the Solar System, only Jupiter and Saturn are within the Sudarsky classification, and both are Class I. The appearance of planets that are not gas giants cannot be predicted by the Sudarsky system, for example terrestrial planets such as Earth and Venus, HD 85512 b (3.6 Earth masses) and OGLE-2005-BLG-390Lb (5.5 Earth masses), or ice giants such as Uranus (14 Earth masses) and Neptune (17 Earth masses). The appearance of extrasolar planets is largely unknown because of the difficulty in making direct observations of extrasolar planets. In addition, analogies with planets in the Solar