Planet (Gas)

Gas planets are characterized by a deep, opaque upper atmosphere, usually composed primarily of light elements such as hydrogen or helium. Simple chemicals can add a range of hues and shades in the visual spectrum, and the interaction between upwellings and rapidly circulating pressure bands result in a huge variety of visible surface structures. A similar level of diversity can be found beneath the cloud-tops: the inner composition of a given gas planet might belong to any one of a dozen broad groups, with no two planets entirely alike in this regard.