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| Quick Facts
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Mass : 5.69 x 10^26 kg (95.2 Earth masses)
Volume : 8.52 x 10^23 m^3 (764 Earth volumes)
Diameter : 120660 km
Mean density : 690 kg/m^3
Escape velocity : 35600 m/sec
Average distance from Sun : 1,430 million km (9.539AU)
Gravity : 1.08 x Earth's
Rotation period/Length of Day : 10.2 Earth hours
Revolution period/Length of Year : 29.46 Earth years
Orbit Eccentricity : 0.056
Orbit Inclination : 2.5 degrees
Obliquity/Tilt of axis : 26.73 degrees
Orbit eccentricity (deviation from circular) : 0.056
Mean temperature : 134 K (1 bar level)
Visual geometric albedo (reflectivity) : 0.46
Rings
Rings are 270,000 km in diameter, but only a few hundred meters thick.
Particles are centimeters to decameters in size and are ice (somemay be covered with ice); there are traces of silicate and carbon minerals. There are four main ring groups and three more faint, narrow ring groups separated by gaps called division.
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| The Ringed Planet
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Saturn is the sixth planet from the Sun and is the second amongst other 9 planets with an equatorial diameter of 119,300 kilometers (74,130 miles). Saturn is slightly flattened at the poles, which is a result of the very fast rotation of the planet on its axis. Its day passes just as fast, which is approximately 10.5 hours long, and it takes 29.5 Earth years to revolve about the Sun. Like the other gas giants ó Jupiter, Uranus, and Neptune ó it probably consists of a dense, solid core surrounded by an envelope of hydrogen and helium and methane. Saturn is the only planet less dense than water (about 30 percent less). If you can find an ocean huge enough, Saturn would actually float on it like a ball.
In Roman mythology, Saturn is the god of agriculture. The associated Greek god, Cronus, was the son of Uranus and Gaia and the father of Zeus (Jupiter). Another fun fact is that Saturn is the root of the English word "Saturday".
Saturn has been known since prehistoric times. Galileo was the first to observe it with a telescope in 1610. Early observations of Saturn were complicated by the fact that the Earth passes through the plane of Saturn's rings every few years as Saturn moves in its orbit. A low resolution image of Saturn therefore changes drastically. It was not until 1659 that Christiaan Huygens correctly inferred the geometry of the rings. Saturn's rings remained unique in the known solar system until 1977 when very faint rings were discovered around the other 3 planets, Uranus, Neptune and Jupiter.
Much of what is known about the planet is due to the Voyager explorations in 1980-81. Saturn is visibly flattened at the poles, a result of the very fast rotation of the planet on its axis. Its day is 10 hours, 39 minutes long, and it takes 29.5 Earth years to revolve about the Sun. The atmosphere is primarily composed of hydrogen with small amounts of helium and methane. Saturn is the only planet less dense than water (about 30 percent less). In the unlikely event that a large enough ocean could be found, Saturn would float in it. Saturn's hazy yellow hue is marked by broad atmospheric banding similar to, but fainter than, that found on Jupiter.
Saturn's ring system makes the planet one of the most beautiful objects in the solar system. Saturn's rings are made of ice and rock. They are not solid, but consist of small bits of frozen material in a layer just a few thousand feet thick. Measured from edge to edge, Saturn's rings span about 600,000 miles (one million km), or two-and-a-half times the distance from Earth to the Moon. The rings are split into a number of different parts, which include the bright A and B rings and a fainter C ring. The ring system has various gaps. The most notable gap is the Cassini Division, which separates the A and B rings. Giovanni Cassini discovered this division in 1675. The Encke Division, which splits the A Ring, is named after Johann Encke, who discovered it in 1837. Space probes have shown that the main rings are really made up of a large number of narrow ringlets. The origin of the rings is obscure. The rings may have formed with Saturn itself, or they may have formed much later, when a small moon or even a large comet passed too near Saturn and was pulled apart by the planet's powerful gravity.
Much of the elaborate structure of some of the rings is due to the gravitational effects of nearby satellites. This phenomenon is demonstrated by the relationship between the F-ring and two small moons that shepherd the ring material.
Although the cloud features on Saturn are not as striking as those on Jupiter, they do change. Winds caused by Saturn's rotation stretch the clouds into horizontal bands circling the planet. At the equator, these winds reach speeds of 1,100 miles (1,770 km) per hour.
| Rings of Saturn |
D RING (inner edge)
Mean Radius (km): 7540
Characteristic: Very thin, not well defined; seen best in forward-scattered light
Discovery: Pioneer 11 1979
C Ring (inner edge) (D Ring outer edge)
Mean Radius (km): 17490
Characteristics: Extremely complicated grooved region ; has many ringlets of regular ordering ; also known as the Crepe Ring
Discovery: W.C. & G.P. Bond & C.W. Tuttle in 1850
Maxwell Gap
Mean Radius : 270
B Ring (inner edge) (C Ring outer edge)
Mean Radius (km): 25580
Characteristics: Brightest ring ; highly complex and intricate; consist of thousands of ringlets; ring spokes; redder particles
Discovery: C. Huygens in 1659
Cassini Division (inner edge) (B Ring outer edge)
Mean Distance (km): 4590
Characteristics: Most prominent gap of all; caused by half-period resonance with Mimas (one of Saturn¹s satellites); faint ringlets
Discovery : G.D. Cassini in 1675
A Ring (inner edge) ( Cassini division outer edge)
Mean Radius (km): 4590
Characteristic: many ringlers & minor gaps; darker & more transparent than B
Discovery: C. Huygens in 1659
Encke Division
Mean Radius (km): 328
Characteristics : Has faint rings
Discovery : J.F. Encke in 1837
Keeler Gap
Mean Radius (km) : 35
F Ring
Mean Radius (km) : Less than 3
Characteristics: "Braided" rings with separate strands; shepherded by Prometheus and Pandora
Discovery : Pioneer 11 1979
G Ring
Mean Radius (km): Unknown
Characteristics: Extremely tenuous and optically thin; seen best with forward scattering light
Discovery : Pioneer 11 in1979
E Ring (approximately inner edge)
Mean Radius (km): 302000
Characteristics: Thought to be sustained by Enceladus; density peaks at the Enceladus¹ orbit
Discovery: Voyager 1 in 1980
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