Saturn and its moons

NASA photo

Saturn, among the most beautiful objects in the sky, is named after the Roman god of agriculture. It is best known for its system of rings, which can be easily viewed from Earth with a modestly powered telescope. From Earth, Saturn appears as one of the brightest objects in the sky and was known even to ancient astronomers.

Physically similar to Jupiter in appearance and composition, Saturn is the second largest planet in the solar system and sixth from the Sun. It is the least dense of the planets, being composed primarily of hydrogen and helium. At Saturn's center is a rocky core, perhaps 10 times of the mass of the Earth. Like Jupiter, Saturn radiates more heat into space than it absorbs; nevertheless, because it has a much lower temperature than Jupiter its clouds are much thicker.

Before NASA sent spacecraft, the most sensitive Earth based telescope had only discovered nine satellites orbiting Saturn. Now at least 22 have been discovered. The Pioneer 11 as well as Voyager I and II spacecraft have greatly expanded mankind's knowledge of Saturn and the other outer planets.

In 2004 the Cassini spacecraft will reach the Saturn system to study the planet and it's moons. A probe will be released into the atmosphere of Titan - one of the most interesting moons in the solar system and the only one with a substantial atmosphere.

NASA photo of the Voyager spacecrafts