Each ring is composed of many ringlets of ice particles, which vary from dust-sized to 3m or more in diameter. Some of Saturn's small moons such as Prometheus appear to keep the rings in place and are known as shepherd moons.
Countless ice particles around Saturn create stunning rings.
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.
A glacial lagoon helps Professor Brian Cox explain Saturn's rings.
Professor Brian Cox visits a glacial lagoon in Iceland to explain why Saturn's rings are so bright.
Brian Cox visits the Saturn probe's mission control.
Professor Brian Cox visits NASA's Jet Propulsion Laboratory, the control centre for the Cassini mission to Saturn. He learns how Saturn can help us understand the early Solar System.
The rings of Saturn are the most extensive planetary ring system of any planet in the Solar System. They consist of countless small particles, ranging in size from micrometres to metres, that orbit about Saturn. The ring particles are made almost entirely of water ice, with a trace component of rocky material. There is still no consensus as to their mechanism of formation; some features of the rings suggest a relatively recent origin, but theoretical models indicate they are likely to have formed early in the Solar System's history.
Although reflection from the rings increases Saturn's brightness, they are not visible from Earth with unaided vision. In 1610, the year after Galileo Galilei first turned a telescope to the sky, he became the very first person to observe Saturn's rings, though he could not see them well enough to discern their true nature. In 1655, Christiaan Huygens was the first person to describe them as a disk surrounding Saturn. Although many people think of Saturn's rings as being made up of a series of tiny ringlets (a concept that goes back to Laplace), true gaps are few. It is more correct to think of the rings as an annular disk with concentric local maxima and minima in density and brightness. On the scale of the clumps within the rings there is much empty space.
The rings have numerous gaps where particle density drops sharply: two opened by known moons embedded within them, and many others at locations of known destabilizing orbital resonances with Saturn's moons. Other gaps remain unexplained. Stabilizing resonances, on the other hand, are responsible for the longevity of several rings, such as the Titan Ringlet and the G Ring.
Well beyond the main rings is the Phoebe ring, which is tilted at an angle of 27 degrees to the other rings and, like Phoebe, orbits in retrograde fashion.