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Saturn, the second largest planet in the solar system and the sixth from the sun, is most noted for its colorful rings. It is unusual in other respects, however. Saturn is the planet whose mass has the least density; just 71 percent that of water. Most of the mass of the planet consists of liquid hydrogen, and it is believed to have a compressed, rocky core. While Saturn has a volume that is 770 times that of Earth, its mass is only 95.2 times that of Earth. Saturn rotates rapidly, so that a point on its equator completes a rotation every 10 hours and 40 minutes. As a result, it is considerably flattened. The polar radius of Saturn, 33,555 miles, is 3,933 miles less than its radius at the equator.