Alien life forms. Artwork of alien life forms in the atmosphere of a gas giant planet. They are being examined by probes. One,at lower left,is labelled as an exobiopod. It is thought that under conditions like those found on Jupiter or Saturn,life may evolve to float using gas-filled buoyancy structures. The organisms would feed on organic debris,or other life forms,using tentacles or by ingesting through mouth-like openings. The atmospheres of gas giants consist mostly of hydrogen and helium,but also contain elements necessary for life to survive,such as oxygen,carbon and nitrogen. Life could only survive in the upper atmospheres,as pressures and temperatures rise swiftly with depth |