Satrurn is the solar system’s second largest planet, behind only Jupiter. At 95 times the mass of the Earth, its gravity commands a region of space hundreds of times the size of the whole inner solar system.

Saturn and its family are more like a miniature solar system in their own right, rather than a planet like our own.

First come the planet’s famous rings, reaching from just above the planet’s cloud-tops out to a distance of 120,000 km, made up of thousands of narrow ringlets, each comprising trillions of lumps of almost pure water ice, varying in size from microscopic snowflakes, to lumps the size of cars.

The ring is the debris of a larger body or moon which was shattered to pieces, most probably by tidal forces as its orbit decayed and it wandered too near to the planet.

It’s hard to imagine tidal forces pulling moons apart, but it can and does happen. The force of gravity depends on distance. The closer a thing is, the greater the gravitational force, so the near side of a moon is always attracted more strongly to the planet than the far side.

The difference between these two forces the tide. Its effect is to try to stretch the body along a line pointing straight down at the planet. If it’s strong enough, the body disintegrates.

Only one thing resists the tidal disruption of a satellite - the body’s own mass, which attracts its own substance towards its centre. As long as this is stronger than the tidal force, all is well.

But when a moon approaches close enough to a planet so that the planet’s pull is stronger than the suface gravity of the moon itself, it’s doomed.

The rings of Saturn were once an ice moon, about 300 km in diameter. To remain as bright as they are they must be around 100 million years old, very young in comparison to the four billion year age of the solar system itself.

They are also unbelievably thin. Despite their huge diameter, the rings are only 10 - 40 metres thick.

A few small moonlets orbit within the ring system, but it is beyond it that the size and number of Saturn’s family really become clear.

No less than 62 satellits are recognised as moons of Saturn, an array of unique worlds in their own right, from the cratered surface of Phoebe to cloud-covered Titan, the second largest moon in the solar system.

The crust of Titan is made of water ice, cold and hard enough at minus 180 degrees Celsius to behave like rock. It’s atmosphere is mostly nitrogen - same as the Earth - in which methane clouds condense and fall as rain, cutting river valleys in the landscape and filling seas and lakes.

Similar chemistry existed on Earth before life began, and Titan is a strong candidate for further biological study.

The moon Iapetus is a piebald mystery. Tidally locked to keep the same face always pointing at Saturn - similar to the tidal locking of our Moon with the Earth - the leading side is as dark as soot, while the trailing side is bright as snow. No-one knows why, though there are many theories. One suggests that the black material may be carbon compounds swept up by the moon in its orbit around Saturn.

This is possibly so, although there are other moons nearby which don’t have black patches on their leading surfaces, and the mystery remains unsolved.

A bizarre mountain ridge also encircles it, like a seam where the two halves of the moon have been badly sewn together - another feature which scientists are struggling to explain.

Poor Phoebe orbits Saturn backwards, opposite that of its larger moons. This indicates that it wasn’t formed in orbit around Saturn, where all bodies - and the planet itself - share the rotational plane from the original cloud of gas and dust from which they condensed. Phoebe is most likely a captured asteroid.

Mimas has a single giant crater on one side, whose formation must have been violent enough to nearly shatter the moon, and is known as the Death Star because of its similarity to the Death Star in Star Wars.

Enceladus is a moon from which ghostly geysers are constantly shooting fountains of water ice hundreds of kilometres into space.

Hyperion is a strange, crushed-looking object, and spins chaotically at a high angle to the plane of its orbit, indicating that it was probably hit relatively recently by a large meteor or asteroid.

The small moon Pan orbits within the main rings and sweeps out a space within them called the Encke Gap.

Pandora and Prometheus are tiny worldlets orbiting together in a gap in the rings, each passing the other, then slowing down to be passed in turn. By their gravity they stabilise the tenuous f-ring, and have been given the lovely name, "Shepherd Moons".