The rings are named alphabetically in the order of discovery. Thus the main rings are, from farthest from the planet to closest, A, B and C. A gap 2, miles wide 4, kilometers , known as the Cassini Division, separates the A and B rings. Other, fainter rings have been discovered as telescope technology has improved.
Voyager 1 detected the innermost D ring in The F ring lies just outside of the A ring, while the G and E ring lay even farther out. The rings themselves contain a number of gaps and structures. Some are created by Saturn's many small moons, while others continue to puzzle to astronomers. Saturn is not the only planet in the solar system to have rings — Jupiter , Uranus and Neptune also contain faint ring systems — but with its satellites spanning three-quarters of the Earth-moon distance , miles or , km , it is by far the largest and most visible.
Several hypotheses exist as to the how Saturn's rings were formed. Some scientists think that passing comets or asteroids were snagged by the planet's gravity and broken up before reaching it. Another possibility is that the rings were once large moons that spiraled into the planet. Saturn has at least 62 moons. One theory that astronomers have come up with is that the rings are actually bits and pieces of an old moon, or moons, that used to orbit Saturn.
In this theory, the old moon was ripped apart somehow. If the ice layers were stripped away, and the rest of the moon crashed in Saturn, rings could be able to form. The pushing and pulling may have caused dust and pieces of the old moon to scatter and orbit around the planet, creating a ring.
Another theory says that the rings may have been formed as debris, dust, comets, and asteroids passed near Saturn. Impacts from asteroids and comets have also altered the appearance of the rings. Late in its mission, the Cassini spacecraft traveled closer to the rings than any other spacecraft.
The probe collected data that is still being analyzed, but it has already provided insights about the colors of some of Saturn's moons.
In the gaps between the rings , the probe found unusually complex chemicals in the "ring rain" of debris falling from the rings into the atmosphere, and made new measurements of the planet's magnetic field, which produces a powerful electron current. Saturn has at least 62 moons. The largest, Titan , is slightly larger than Mercury, and is the second-largest moon in the solar system behind Jupiter's moon Ganymede. Earth's moon is the fifth largest.
Some of the moons have extreme features. Pan and Atlas are shaped like flying saucers; Iapetus has one side as bright as snow and one side as dark as coal. Enceladus shows evidence of "ice volcanism": a hidden ocean spews out water and other chemicals from the geysers spotted at the moon's southern pole. A number of these satellites, such as Prometheus and Pandora, are referred to as shepherd moons because they interact with ring material and keep the rings in their orbits.
Though scientists have identified many moons, Saturn has other small moons constantly being created and destroyed. As the most massive planet in the solar system after Jupiter, the pull of Saturn's gravity has helped shape the fate of our solar system.
It may have helped violently hurl Neptune and Uranus outward. Along with Jupiter, it might also have slung a barrage of debris toward the inner planets early in the system's history. Scientists are still learning about how gas giants form, and run models on early solar system formation to understand the role that Jupiter, Saturn and other planets play in our solar system.
A study suggests that Saturn, more so than Jupiter, steers dangerous asteroids away from Earth. The first spacecraft to reach Saturn was Pioneer 11 in , flying within 13, miles 22, km of the Ringed Planet.
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