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So far, 62 moons have been discovered orbiting Saturn. Jupiter is the only planet with more moons – it has 63. Most of Saturn’s satellites were not discovered until after 1950 because astronomers were working with less advanced telescopes. Dozens of Saturn’s moons were discovered in the last decade. Recently, scientists have also found moons in the gaps of the planet’s rings.
Saturn’s largest satellite, Titan, is the second largest moon in the Solar System. Larger than Earth’s Moon, Titan has a diameter of 5,150 kilometers, which is 75% of Mercury’s diameter. The moon also accounts for more than 96% of the mass of Saturn’s satellites. The planet’s six other large moons – Mimas, Enceladus, Tethys, Dione, Rhea, and Iapetus – comprise about 4% of Saturn’s mass, which means the other 55 moons only make up about 0.04% of the planet’s mass.
It was not until the 1980’s when a probe visited Titan that scientists were able to discover that the moon was actually smaller than Ganymede, the Solar System’s largest moon. This was due to Titan’s very dense atmosphere, which made the satellite appear larger than it actually is. Titan is the only moon in our Solar System to have an atmosphere like this. Rhea is Saturn’s second largest satellite with a diameter of 1,530 kilometers and a mass of 23×1020 kg, which is only 3% of the Moon’s mass. Mimas, named after a son of Gaia, is the smallest of Saturn’s seven major satellites with a diameter of 400 km, which is only 12% of the Moon’s diameter. Mimas’ mass is only half of a percent of the Moon’s mass. The other major moons, except for Titan, all have diameters that are less than half of the Moon’s diameters and are less than 5% of its mass.
Only 53 of the planet’s moons are named. John Herschel, whose father – William Herschel – discovered two of Uranus’ moons, suggested names for many newly discovered moons and proposed naming Saturn’s moons after mythological figures associated with Cronos, the Greek equivalent of Saturn. Titan and some of the other moons were named after the children of Cronos. Eventually, as more moons were discovered other names from Greek mythology as well as other cultures had to be used. In fact, the names are often split into subcategories according to what culture’s gods they were named after. The Inuit group contains five moons named after Inuit gods. The names for the four Gallic moons were taken from Gallic mythology while the Norse group has 29 moons.
Astronomy Cast has an episode on Saturn’s moons.