Solar System Exploration: Planet Selector: Saturn

PLANET SELECTOR

ABOUT SATURN

Adorned with thousands of beautiful ringlets, Saturn is unique among the planets. All four gas giant planets have rings - made of chunks of ice and rock - but none are as spectacular or as complicated as Saturn's. Like the other gas giants, Saturn is mostly a massive ball of hydrogen and helium.
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Featured Mission: Cassini
In July, 2004, Cassini began extensive study of Saturn, its rings, its more than 56 moons from orbit. In December, 2004 it released the Huygens Probe to study Saturn's largest moon, Titan.
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VITAL STATISTICS

Average Distance from Sun:	1,426,725,400 km (886,526,100 miles)
Diameter:	116,464 km (72,367 miles)
Volume:	755 x Earth's
Mass:	568,460,000,000,000,000,000,000,000 kg (95.16 x Earth's)
Length of Day:	10.656 Earth hours
Length of Year:	29.45 Earth years
Known Moons:	56

SIZE & DISTANCE

As Saturn is about 9 times larger than Earth, if Saturn was the size of a soccer ball, Earth would be about as big as a nickel.

Average Distance from the Sun: 1,426,725,400 km (9.54 A.U.)

EXTREME SPACE

Spectacular Spacecraft
The Cassini spacecraft now orbiting Saturn is the largest interplanetary spacecraft ever built. With a total mass of about 5,650 kilograms (6 tons), the two-story tall spacecraft is roughly equal in mass to an empty 30-passenger school bus.

Mega Crater
Saturn's moon Mimas sports a massive impact crater more than 130 km (81 miles) across and 5 km (3 miles) deep. The battered moon is only 400 km (249 miles) across. A crater of the same proportion on Earth would cover the entire United States.

Cosmic Bath Toy
It's hard to imagine, but Saturn is the only planet in our solar system that is less dense than water. The giant gas planet could float in a bathtub - if such a colossal thing existed.

Lord of the Rings
Even though Saturn's rings are more than 250,000 km (155,000 miles) across - most of the distance between Earth and its Moon - they are less than one kilometer (3,200 feet) thick. The rings - ranging in size from a pebble to a house - are probably the remains of a shattered moon or comet.

Slow Ride
If you retraced the 3,200,000,000 km (1,988,000,000 miles) Cassini traveled to reach Saturn in a car at 100 kph (62 mph), the ride would last about 3,653 years. Fortunately, spacecraft are much faster. Cassini will make the trip in less than seven years.

True Titan
Saturn's haze-covered moon Titan is larger than the planets Mercury and Pluto. Among moons, only Jupiter's Ganymede is larger. Titan is the only moon in our solar system with an atmosphere thicker than Earth's.

TIMELINE

1611 - Italian astronomer Galileo Galilei first sees odd appendages on either side of Saturn - the planet's rings viewed nearly edge-on.

1944 - Gerald Kuiper discovers methane in the atmosphere of Saturn's moon Titan.

1979 - NASA's Pioneer 11 is the first spacecraft to reach Saturn when it flies within 22,000 km (13,700 miles) of the ringed planet.

1980 - Voyager 1 uses Saturn's powerful gravity as a slingshot that gives it enough speed to be the first manmade object to leave our solar system.

1994 - NASA's Hubble Space Telescope spots evidence of surface features beneath the hazy atmosphere of Saturn's moon, Titan.

2004-now - After a seven-year journey, the Cassini-Huygens spacecraft became the first to orbit Saturn. 2005 marked the successful landing of the Huygens probe onto the surface of Titan. Cassini also discovered plumes on the icy moon Enceladus.

SLIDE SHOW

Approaching Saturn
Saturn with moons Tethys and Dione
Edge-On View of Saturn's Rings
Saturn Rings (False Color)
Saturn's Clouds
Giant Crater on Mimas
Best View of Titan's Surface
Saturn's Aurora
Saturn and Earth's Moon
Traveling Beyond Saturn

MOONS

Saturn ranks second in the moon count with 34 known moons. Many are fascinating worlds, but few are more compelling than Titan. Bigger than the planets Mercury and Pluto, Titan is the only moon in our solar system with a planet-like atmosphere. The thick, hazy atmosphere may contain the same basic chemicals as primordial Earth. It also hides the surface of Titan from telescopes and visible-light cameras.