Facts about the planet Saturn Diameter: 120,660 km. It is about 10 times larger than our Earth Temperature: –178°C Distance from Earth: At its closest, Saturn is 1190.4 million km Atmosphere: Hydrogen and helium Surface: consists of liquid and gas. Rotation of its axis: 10 hours, 40 min, 24 sec Rotation around the Sun: 29.5 Earth years Solar Distance 1.429 billion km Revolution Period 29.46 Earth years Rotation Period 10 hours 40 minutes Equatorial diameter 120,660 km Gravitational Pull 0.93 times that of the Earth Natural Satellites 35 (possibly more) [edit] All About Saturn Saturn is the second largest planet in our solar system, making it about 95 times larger than the Earth! The sixth planet out from the sun, it takes Saturn about 29.5 years to orbit the sun one time, traveling a distance of roughly 1,426,000,000 kilometers for one single revolution

Saturn: History Timeline 1655 Saturn’s rings seen by Galileo, who thinks them twin moons 1655 Huygens discovers Titan, Saturn’s largest moon 1977 Rings are found on other planets 1979 Pioneer 11 flies by 1980 Voyager 1 flies by 1981 Voyager 2 flies by 1990 Pan, Saturn’s eighteenth known moon, is the latest discovered

[edit] Astronomers that contributed to Saturn Saturn has been known since prehistoric times because it is easily visible to the naked eye. Not until the invention of the telescope, however, did people observe Saturn's magnificent rings. Galileo Galilei was the first to observe Saturn with a telescope in 1610. Because of the crudeness of his telescope, he couldn't determine what the rings were. He incorrectly guessed that there were two large moons on either side of Saturn. Two years later when he viewed Saturn again, the "moons" had disappeared. We know now this is because Galileo was viewing the rings edge-on so that they were invisible, but at the time it was very confusing to Galileo. After another two years, Galileo viewed Saturn again and found that the "moons" had returned. He concluded that the rings were "arms" of some sort.

Galileo & his drawings

Top drawing: Galileo's drawing of Saturn, 1610

Bottom drawing: Galileo's drawing of Saturn, 1616

Many years later, in 1659, a Dutch astronomer named Christiaan Huygens solved the mystery of Saturn's "arms." Because of improved telescope optics, he correctly deduced that the "arms" were actually a ring system. Huygens also discovered Saturn's moon, Titan, and for this reason, the probe exploring Titan is named after him.

Christian Huygens

A few years after Huygens' discoveries, an Italian-French astronomer by the name of Jean- Dominique Cassini discovered 4 other major moons of Saturn: Iapetus, Rhea, Tethys, and Dione. In 1675, Cassini discovered a narrow gap that splits Saturn's ring system into two parts, and the gap has since been known as the "Cassini Division." Because of his numerous contributions to our knowledge about the planet Saturn, Cassini was chosen as the name of the spacecraft flying to Saturn.

Jean-Dominique Cassini

Other major discoveries came later. During the 19th century, J.E. Keeler showed that the ring system is not a uniform sheet but actually comprised of small particles. Most recently, the Voyager spacecrafts (visiting in 1980-81) made discoveries about the composition and interaction of the rings.

[edit] SATURNS RINGS&MOONS. Saturn's rings cut across a scene that is ruled by Titan's luminous crescent and globe-encircling haze, broken by the small moon Enceladus, whose icy jets are dimly visible at its south pole. North is up.Saturn is currently thought to have sixty-three moons, many of which were discovered very recently, including three particularly un-confirmed, hypothetical moons. However, a precise number of moons can never be given, as there is no objective dividing line between the anonymous orbiting fragments that form Saturn's ring system and the larger objects that have already been named as moons.

Before the advent of telescopic photography, eight moons of Saturn were discovered by direct observation using an optical telescope:

Titan, discovered in 1655 by Christiaan Huygens; Tethys, Dione, Rhea and Iapetus (the "Sidera Lodoicea") discovered 1671-1684 by Giovanni Domenico Cassini; Mimas and Enceladus, discovered 1789 by William Herschel; Hyperion, discovered 1848 by W.C. Bond, G.P. Bond and Lassell. The spurious satellite Chiron, "discovered" in 1861, is now known not to exist. The use of long-exposure photographic plates made it possible to discover additional moons:

Phoebe was the first satellite discovered by telescopic photograph in 1899 by W.H. Pickering. Themis, "discovered" in 1905, also was later proven not to exist. In 1966, the satellites Janus and Epimetheus were observed, but not confirmed, and it was not realized that there were two distinct moons sharing an orbit. The study of the outer planets has since been revolutionized, first by the use of unmanned space probes, and then by advances in telescopy:

From 1980, when the first of the Voyager space probes arrived at Saturn, to 1990, analysis of Voyager images revealed eight more moons in the inner Saturnian system. The last discovered was Pan. A survey starting in late 2000 found thirteen new moons orbiting Saturn at a great distance in orbits that suggest they are fragments of larger bodies captured by Saturn's gravitational pull (Nature vol. 412, pp. 163–166). The Cassini mission, which arrived at Saturn in the summer of 2004, discovered three small moons in the inner Saturnian system as well as three suspected but unconfirmed moons in the F Ring. This increased the total to thirty-seven moons, confirmed and unconfirmed. On November 16, 2004, Cassini scientists announced that the structure of Saturn's rings indicates the presence of several more moons orbiting within the rings, but only one, Daphnis, has been visually confirmed so far (its confirmation was announced on May 6, 2005).[1]. On May 3, 2005, astronomers using the Mauna Kea Observatory announced the discovery of twelve more small outer moons [2] [3]. On June 30, 2006, astronomers using the Subaru 8.2 m telescope announced the discovery of nine more small outer moons [4]. On April 13, 2007, S/2007 S 1 was announced. On May 1, 2007, S/2007 S 2 and S/2007 S 3 were announced. On July 18, 2007, Anthe was announced.