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What Are the Features of Saturn?

Saturn, the sixth planet from the sun, is second only to Jupiter in size and mass. Saturn is one of the brightest objects in the night sky and has been observed by humans since prehistoric time. The U.S. space agency has sent four missions to explore Saturn: Pioneer 11 (1979), Voyager 1 (1980), Voyager 2 (1982) and the Cassini-Huygens spacecraft (2004). Each mission required scientists to revise what they thought they knew about this mysterious planet.

General Facts
- The brightness of sunlight on Saturn is only 1 percent that on Earth.
  
  Saturn is 74,565 miles in diameter and is 888,740,000 miles from the sun. A day on Saturn is 10 hours, 39.4 minutes long, and the planet takes 29.46 Earth years to orbit the sun. It has an orbital inclination of 2.488 degrees and an axis inclination of 26.73 degrees. Saturn's magnetic field is 8,000 times greater than Earth's.
Rings
- Saturn's innermost ring appears knotted or braided.
  
  Saturn's best-known feature is the rings that encompass the planet. Once believed to be two rings, it is now known to be a complex system of thousands of rings and elaborate spiral structures made primarily of water and ice. They span 175,000 miles but are less than a mile thick. It is believed that they were formed by two satellites crashing together only a few thousand years ago and that their material is gradually falling to the planet's surface. It is estimated that 100 million years from now, the rings will be gone.
Moons
- The Cassini-Huygens spacecraft spent six years on Titan.
  
  Recent evidence has shown that Saturn has at least 62 moons in its orbit; seven of them are quite large. The largest, Titan, is larger than the planet Mercury.
Composition
- Saturn's core is made up of rock and ice.
  
  Saturn is similar in chemical composition to Jupiter. It is about 75 percent hydrogen and 25 percent helium, with traces of methane, water and ammonia. Its core is believed to be made up of rock and ice, surrounded by a layer of liquid metallic hydrogen. The planet has no solid surface. It is the least dense planet and is the only one less dense than water; if it could be placed in a giant body of water, it would float.
Polar Vortex
- Wind on Saturn blows at 1,100 miles per hour.
  
  Saturn's polar vortex was discovered on Oct. 11, 2006, by the Cassini-Huygens spacecraft. It was found to be a massive whirling hurricane-like feature. Like hurricanes on Earth, the eye is nearly free of clouds; however, it is much larger than any hurricane on earth. The eye alone is about 2,500 miles in diameter, whereas on Earth, the eye of a typical hurricane is about 2 to 3 miles in diameter.
Radio Emissions
- The Cassini-Huygens spacecraft detected radio waves from Saturn in April 2002.
  
  Saturn has intense radio emissions that appear much like the auroras of Earth's northern and southern lights, with an amazing array of variations in frequencies and time.

Astronomy