Saturn - the ring system planet

General Information

Average distance from the Sun

1,427 million km
(887 million miles)

Length of year

29.5 Earth years

Average rotation period

10 hours 32 minutes

Diameter at equator

120,420 km
(78,840 miles)

Approximate surface temperature

- 180 0C


Saturn, like the other gas giants, is made mainly of hydrogen and helium. It has the lowest density of all the planets, only seven tenths that of water.

Saturn has a density lower than water, so if there was a tub of water big enough,
Saturn would float in it

Astronomers think Saturn has a small rocky core. Over the core is a thick layer of liquid hydrogen. The deepest parts of this layer are under so much pressure that the hydrogen acts like a molten metal. Like on Jupiter, the out cloud layers gradually merge with the liquid underneath, and there is no definite surface.

Viewed from Earth, three main rings can be seen around Saturn, separated by dark gaps. The rings consist of many individual pieces of a mixture of ice dust, ranging in size from a few centimetres to a few metres across.



The exact number of Saturn's moons is unknown. However, astronomers using Earth-based telescopes have identified eleven moons orbiting Saturn. Saturn's largest moon, Titan, is particularly interesting: it is the only moon in the Solar System with a thick atmosphere. Titan appears orange in colour, but its opaque atmosphere prevents us seen in the surface.