EVERYTHING YOU NEED TO KNOW ABOUT SATURN

With its moon system, rings of dust and ice and occasionally tempestuous atmosphere, there’s more to this gas giant than meets the eye

- Giles Sparrow

Saturn is our Solar System’s ringed wonder – a spectacular world encircled by planes of icy debris, giving it a unique appearance. But there’s a lot more to Saturn than just its rings; this enormous world is worth exploring both for its own complexity and the fascinating family of satellites that orbit it. As the most distant Solar System object easily seen with the naked eye, Saturn orbits at an average of 1.43 billion kilometres (887 million miles) from the Sun. Its slow orbit means that Saturn takes 29.5 years to make a full circuit through the constellations of the zodiac; it was this stately movement that led ancient stargazers to associate it with the father of Jupiter in Roman mythology.

Its distance makes it a challenging object for study, even in the era of giant telescopes. Most of what we know about the planet comes from the Voyager probe flybys in the 1980s and the Cassini mission that orbited between 2004 and 2017. Earth observations, coupled with close-up images from these explorers, have revealed that what often appears to be a placid orb of creamy cloud is in fact a surprisingly active world.

Internally, Saturn is a gas giant like Jupiter, a huge ball dominated by the lightweight elements hydrogen and helium. It owes its very different outward appearance to a substantially lower mass – Saturn weighs as much as 95 Earths, but this is less than a third of Jupiter. The weaker gravity allows Saturn’s upper layers to billow outwards, giving it the lowest average density of any world in the Solar System – about two-thirds that of water.