Saturn, the sixth planet from the Sun, has beautiful rings composed of ice particles. It is the second largest planet in the Solar System, yet it is the least dense - it would float in water if there were a bathtub large enough to hold it.
Saturn is mainly composed of hydrogen and helium and does not have a solid surface. It has 25 satellites that measure at least 10km in diameter - the largest, Titan, is the only moon in the Solar System with a substantial atmosphere.
Saturn's interior is thought to contain fluid metallic hydrogen - a substance that cannot be studied directly because it is not possible to recreate the very high temperatures and pressures at which it is predicted to form.
Photo: Saturn taken by the Cassini probe (NASA/JPL/Space Science Institute)
The ringed planet is a complex world.
The probe finds clues about the age of Saturn's rings.
The mass spectrometer aboard the Cassini probe, launched in 1997, was used to analyse the age of Saturn's rings – with results no scientist could predict. The instrument produced images showing the dust content in the rings as a series of reds and blues. Dust content is believed to be a key clue to the rings' age.
Voyager images start scientists wondering about the age of Saturn's rings.
Images of Saturn's ring system returned by the Voyager probes, launched in 1977, kindled scientists' interest in these bands of shattered moon debris.
Careful study explains Saturn's mysterious ring spokes.
Professor Carolyn Porco unravelled the mystery of Saturn's ring spokes, which turned out to be clouds of dust trapped in Saturn's magnetic field.
Sir Patrick Moore's guests discuss Saturn's magnetic field and storms.
Sir Patrick Moore spoke to his guests, Professor John Zarnecki from the Open University and Professor Michele Dougherty from Imperial College, about Saturn's core, magnetic field and storms shortly after the Cassini-Huygens probe reached the ringed planet in 2004.
Sir Patrick Moore looks at Cassini-Huygens's first images of some of Saturn's moons.
Sir Patrick Moore has a look at the Cassini-Huygens probe's first images of some of Saturn's icy moons - Phoebe, Mimas, Tethys and Iapetus - and discusses the mission with his guests.
Saturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Named after the Roman god of agriculture, its astronomical symbol (♄) represents the god's sickle. Saturn is a gas giant with an average radius about nine times that of Earth. While only one-eighth the average density of Earth, with its larger volume Saturn is just over 95 times more massive.
Saturn's interior is probably composed of a core of iron, nickel and rock (silicon and oxygen compounds), surrounded by a deep layer of metallic hydrogen, an intermediate layer of liquid hydrogen and liquid helium and an outer gaseous layer. The planet exhibits a pale yellow hue due to ammonia crystals in its upper atmosphere. Electrical current within the metallic hydrogen layer is thought to give rise to Saturn's planetary magnetic field, which is weaker than Earth's magnetic field but has a magnetic moment 580 times that of the Earth due to Saturn's larger body radius. Saturn's magnetic field strength is around one-twentieth the strength of Jupiter's. The outer atmosphere is generally bland and lacking in contrast, although long-lived features can appear. Wind speeds on Saturn can reach 1,800 km/h (500 m/s), faster than on Jupiter, but not as fast as those on Neptune.
Saturn has a prominent ring system that consists of nine continuous main rings and three discontinuous arcs, composed 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 does not include the hundreds of "moonlets" comprising the rings. Titan, Saturn's largest and the Solar System's second largest moon, is larger than the planet Mercury and is the only moon in the Solar System to retain a substantial atmosphere.