Throughout April, Saturn, the sixth planet from our sun, will be high in the night sky. More than 9.5 times further from the sun than is Earth, the ringed planet takes 29.5 years to complete its orbit; on the other hand, Saturn has a rapid rotation, completing its day in 10.5 hours.
One of the gas planets (which also include Jupiter, Neptune and Uranus), Saturn has an equatorial diameter of 74.5 thousand miles, more than 9 times that of the Earth. It is composed primarily of hydrogen and helium, surrounding a core of molten rock; ammonia, methane, water and other compounds are found in lesser amounts. Storms and high winds characterize the atmosphere and, in 2006, the Cassini spacecraft documented the presence of a large, hexagon-shaped, hurricane-like storm over Saturn's south pole.
But Saturn is most famous for its rings, which are composed of ice, dust and rocky debris. While they have a diameter of 150,000 miles, the rings are less than 1 mile thick. Their changing appearance suggests to astronomers that they are relatively young (perhaps less than ten million years old) and that they may have originated from the collision of a comet with one of Saturn's moons. Not to worry: the planet still has sixty moons, half of which are named; Titan, its largest satellite, is the only moon in our solar system to have a significant atmosphere.
