Saturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Saturn is named after the Roman god Saturn, equated to the Greek Cronus (the Titan father ofZeus), the Babylonian Ninurta, and the Hindu Shani. Saturn's symbol represents the Roman god's sickle (Unicode: ♄).
Saturn, along with Jupiter, Uranus, and Neptune, is classified as a gas giant. Together, these four planets are sometimes referred to as the Jovian, meaning "Jupiter-like", planets. Saturn has an averageradius about 9 times larger than the Earth's. While only 1/8 the average density of Earth, due to its larger volume, Saturn's mass is just over 95 times greater than Earth's.
Because of Saturn's large mass and resulting gravitation, the conditions produced on Saturn are extreme. The interior pressures and temperatures are beyond what can be reproduced experimentally on Earth. The interior of Saturn is probably composed of a core of iron, nickel, silicon and oxygen compounds, surrounded by a deep layer of metallic hydrogen, an intermediate layer of liquid hydrogen andliquid helium, and an outer gaseous layer. Electrical current within the metallic-hydrogen layer is thought to give rise to Saturn's planetary magnetic field, which is slightly weaker than Earth's magnetic field and approximately one-twentieth the strength of the field around Jupiter. The outer atmosphere is generally bland in appearance, although long-lived features can appear. Wind speeds on Saturn can reach 1,800 km/h, significantly faster than those on Jupiter.
Saturn has nine rings, consisting mostly of ice particles with a smaller amount of rocky debris and dust. Sixty-two known moons orbit the planet; fifty-three are officially named. This is not counting hundreds of "moonlets" within the rings. Titan, Saturn's largest and the Solar System's second largest moon (after Jupiter's Ganymede), is larger than the planet Mercury and is the only moon in the Solar System to possess a significant atmosphere.