Giant Planet
From Jolkein
Giant Planet is planet whose diameter is more than 50,000 km across and is mainly made up of gases and other elements with no solid surface. There are two categories for this type of planet Gas Giants and Ice Giants
[edit] Gas Giant
Gas giants are large and massive planets composed chiefly of various gases. They had no solid, well-defined surface, which rendered them uninhabitable in themselves, but at least some of them had a large number of moons. Typically, gas giants harbored little life unless their atmosphere comprised a layer capable of supporting oxygen -breathing species. Another characteristic of those worlds was the presence of planetary rings made up of several million pieces of debris. In some cases, those debris were rocky in nature and rich in ore.
Due to their significant masses, such planets had gravity wells that created distinct, if minor, hazards for hyperspace travel. Under certain circumstances, a particularly enormous gas giant could become a star in its own right.
[edit] Ice Giant
An ice giant is a giant planet composed mainly of elements heavier than hydrogen and helium, such as oxygen, carbon, nitrogen, and sulfur.
In astrophysics and planetary science the term "ices" refers to volatile chemical compounds with freezing points above about 100°K, such as water, ammonia, or methane, with freezing points of 273°K, 195°K, and 91°K, respectively. In the 1990s, it was realized that Uranus and Neptune are a distinct class of giant planet. They have become known as ice giants. Their constituent compounds were solids when they were primarily incorporated into the planets during their formation, either directly in the form of ices or trapped in water ice. Instead, H2O primarily exists as supercritical fluid at the temperatures and pressures within them.
Ice giants consist of only about 20% hydrogen and helium in mass, as opposed to gas giants, which are both more than 90% hydrogen and helium in mass.
