Saturn is the sixth planet from the Sun and the second largest next to Jupiter. It is known by its prominent system of rings that extend out far into space. The planet has an equatorial diameter of 119,300 kilometers (74,130 miles) and orbits the Sun at a mean distance of 1,429,400,000 kilometers (9.54 AU). Its mass is 5.68 x 10^26 kilograms.
Saturn has been observed since the prehistoric times due to its brightness in the sky. In 1610, Galileo was the first to see Saturn with a telescope, but was unable to successfully understand its shape. The reason being is that due to its orbital orientation with Earth, its rings virtually become invisible to astronomers because Earth passes into the planet of the rings every few years. Thus, through low powered magnification, Saturn appears to be round at times while at other times, it seems to be oddly shaped. However, this was explained in 1659 when Christian Huygens accurately determined the geometry of Saturn's rings. Because the technology necessary to examine other planets more closely did not come until modern times, most people thought that Saturn was the only planet in the solar system to have rings that the feature was unique. However, in 1977, it was discovered that Uranus had rings as well as Jupiter and Neptune. The findings were a big surprise, but helped astronomers and scientists to understand that rings are a common feature to planets. Many of Saturn's characteristics were revealed by the Voyager missions that took place in 1980-1981.
In Roman mythology, Saturn is the god of agriculture and is associated with the Greek God, Cronus. Cronus is the son of Uranus and Gaia.
- Introduction to Saturn