Planet Saturn: Facts About Saturn’s Rings, Moons & Size

Saturn’s famous rings are spectacular. The most recently discovered ring is at least 200 times the diameter of the planet and could fit one billion Earths.
Credit: NASA/JPL



Physical characteristics of Saturn

Saturn is a gas giant made up mostly of hydrogen and helium. Saturn is bigenough to hold more than 760 Earths, and is more massive than any other planet except Jupiter, roughly 95 times Earth's mass. However, Saturn has the lowest density of all the planets, and is the only one less dense than water — if there were a bathtub big enough to hold it, Saturn would float.

The yellow and gold bands seen in Saturn's atmosphere are the result of super-fast winds in the upper atmosphere, which can reach up to 1,100 mph (1,800 km/h) around its equator, combined with heat rising from the planet's interior.

Saturn spins faster than any other planet except Jupiter, completing a rotation roughly every 10-and-a-half hours. This rapid spinning causes Saturn to bulge at its equator and flatten at its poles — the planet is 8,000 miles (13,000 kilometers) wider at its equator than between the poles.


Other titanic storms appear in Saturn’s atmosphere once every Saturn year (approximately 30 Earth-years), disrupting the temperature and winds of the planet’s skies. Six such storms have been observed on the planet since 1876, but in 2011, NASA’s Cassini spacecraft became the first orbiter to observe one.

Like other giant planets, Saturn also has northern and southern lights, caused by particles from the sun.

Credit: Karl Tate, SPACE.com

Composition & structure

Atmospheric composition (by volume): 96.3 percent molecular hydrogen, 3.25 percent helium, minor amounts of methane, ammonia, hydrogen deuteride, ethane, ammonia ice aerosols, water ice aerosols, ammonia hydrosulfide aerosols

Magnetic field: Saturn has a magnetic field about 578 times more powerful than Earth's.


Internal structure: Saturn seems to have a core between about 10 to 20 times as massive as Earth.

Orbit & rotation

Average distance from the sun: 885,904,700 miles (1,426,725,400 km). By comparison: 9.53707 times that of Earth.

Perihelion (closest approach to sun): 838,519,000 miles (1,349,467,000 km). By comparison: 9.177 times that of Earth.

Aphelion (farthest distance from sun): 934,530,000 miles (1,503,983,000 km). By comparison: 9.886 times that of Earth.

Saturn's moons


Saturn's largest moon, 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.) Titan is veiled under a very thick, nitrogen-rich atmosphere that might be like what Earth's was long ago, before life. While the Earth's atmosphere extends only about 37 miles (60 km) into space, Titan's reaches nearly 10 times as far. The atmosphere contains a number of hydrocarbons, chemicals that primarily make up fossil fuels on Earth. Methane rain falls from the sky and moves through the moon’s icy crust. A recent study detected propylene, a chemical used to make plastics, in the planet’s atmosphere.

These moons can possess bizarre 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," spewing out water and other chemicals from the 101 geysers spotted at the moon’s southern pole. A number of these satellites, such as Prometheus and Pandora, are shepherd moons, interacting with ring material to keep rings in their orbits.

Though scientists have identified many moons, the chaotic system has other small moons constantly being created and destroyed.


Saturn's rings




Mysterious spokes have been seen in Saturn's rings, which might form and disperse over a few hours. Scientists have conjectured these spokes might be composed of electrically charged sheets of dust-sized particles created by small meteors impacting the rings or electron beams from the planet's lightning. Saturn's F Ring also has a curious braided appearance — it is composed of several narrow rings, and bends, kinks, and bright clumps in them can give the illusion that these strands are braided. Changes in the rings of Saturn, as well as the rings of Jupiter, are caused by impacts from asteroids and comets.

Saturn's gravitational impact on the solar system


Research & exploration


The Cassini spacecraft now in orbit around Saturn is the largest interplanetary spacecraft ever built, a two-story-tall probe that, at 6 tons in weight (5,650 kilograms), is roughly equal in mass to an empty 30-passenger school bus. It discovered plumes on the icy moon Enceladus, and carried the Huygens probe, which plunged through Titan's atmosphere to successfully land on its surface. After a decade of observation, Cassini has returned incredible data about the planet and its moons, as well as a photo recreating the original “Pale Blue Dot” image, which captures Earth from behind Saturn, in 2013.

Additional reporting by Nola Taylor Redd, Space.com Contributor

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Charles Q. Choi

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