Beyond the Trojan Reach
A large planet with an extensive atmosphere of hydrogen and hydrogen compounds. Jupiter, in the Terra system, is an example of a gas giant.
Gas giants may have a rocky or metallic core—in fact, such a core is thought to be required for a gas giant to form—but the majority of its mass is in the form of the gaseous hydrogen and helium, with traces of water, methane, ammonia, and other hydrogen compounds. Gas giants do not have a well-defined surface; their atmospheres simply become gradually denser toward the core, perhaps with liquid or liquid-like states in between. Thus, terms such as diameter, surface area, volume, surface temperature and surface density refer only to the outermost layer visible from space.
Starships fuel themselves by flying through the very upper traces of this atmosphere and skimming hydrogen from it. This is often called frontier refueling. Only streamlined vessels may undertake this maneuver. While useful, this maneuver is not without its hazards both from the atmosphere of the gas giant, as well as opening the skimming ship up to attack. Since gas giants are useful sources of fuel for starships, their presence within a system is usually noted in navigation charts.
The Solomani sometimes refer to gas giants as a Jovian planet after the planet Jupiter in their home system.