The solar system contains four gas giants, which include Jupiter, Saturn, Uranus and Neptune. They were given this name due to the enormous amount of gases they contain in their mass. These "four giant planets are comprised mostly of an outer layer of molecular hydrogen and helium and a much thicker layer of metallic hydrogen. However, each may have a small solid core as large as three to 20 Earth masses at their center," according to the Solstation website.
Jupiter is the closest gas giant to Earth and is the largest of all the gas giants. Hundreds of planets the size of Earth could fit within its great mass, one so large it is nearly at maximum size for any gas giant. It is named after the Roman king of the gods.
Saturn is another of the gas giants and is most notable for the prominent rings that encircle it. The rings are predominantly made up of water but they also contain a small percentage of dust and planetary debris. The planet can be found beyond Jupiter.
Uranus is one of two gas giants that is also sometimes called an ice giant. This planet is beyond Saturn. It is one of two planets that "probably have large fractions of oxygen, carbon, nitrogen, and sulfur," according to the Solstation site.
Beyond Uranus is Neptune, which is the second gas giant that is also known as an ice giant. Like Uranus, it is thought to contain an abundance of oxygen, carbon, nitrogen and sulfur. Neptune, like its sister planet, is much smaller than Jupiter and Saturn.