Space Facts

Planet Saturn

Beautiful Ring

This NASA Cassini spacecraft image mosaic combines 30 images taken over the course of approximately two hours as Cassini panned its wide-angle camera across the entire planet and ring system on July 23, 2008. Viewed from a distance of approximately 1.1 million kilometers (690,000 miles) from Saturn. Image Credit: NASA/JPL/Space Science Institute

Saturn is planet number six of the Solar system. The planet is named for the Roman god Saturnus (where we get our word "Saturday"), a god of agriculture and harvest, and father of Jupiter. Saturnus was associated with the Greek titan, Cronus.

The planet Saturn is most noted for its beautiful ring structure. All of the Solar system's gas giants have rings, but none as visually stunning as that of Saturn. The planet is also noted for being extremely light weight, or more aptly put, less dense than any other planet in the Solar system. In fact, it is less dense than water, giving rise to the notion that, if a big enough body of water could be found, Saturn would float.

The rings are thought to be the result of debris from the original formation of the Solar system that could not combine to form a moon because of the strong tidal effects of Saturn's nearby gravity well. All of the rings are said to be within what is called "Roche's limit" — a distance within which a moon might be torn apart by tidal forces.

Saturn has an equatorial diameter of about 120,500 kilometers (74,900 miles). That's about 9.5 times the diameter of Earth. Its day is 10.656 hours and its year is 29.46 Earth years long. The average distance of Saturn from the sun is 1.433 billion kilometers (891 million miles). Saturn has its own family of moons. The largest moon in the Solar system is Saturn's moon Titan (5,150 km, 3,201 miles diameter). Seven other major moons range in diameter from 1,528 kilometers (950 miles) down to 418 kilometers (260 miles). Another 52 smaller satellites complete Saturn's currently known family, diameters ranging from about 230 kilometers (143 miles) down to 6 kilometers (3.7 miles). Most of these lesser moons are under 10 kilometers wide.

Size comparison of gas giant planets with Earth (left to right): Earth, Jupiter, Saturn, Uranus, and Neptune.		The last four planets of the Solar system are called "gas giants" because the bulk of each such planet is gaseous. The other type of planet is called "terrestrials" because of their rough similarity to Earth. The Solar System Facts table gives more comparisons between the planets.

Could Saturn Ever Sustain Life?

As with Jupiter, the planet Saturn is a gas giant without any solid surface. Even farther from the sun than the king of planets, Saturn is comparably colder.

Saturn's largest moon, Titan, is the only natural satellite in the Solar system with an appreciable atmosphere, but it is a cold, methane soup — not very hospitable.

If interplanetary travel ever becomes commonplace, a honeymoon in orbit around Saturn might become a tradition. How romantic!

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