The sixth planet from the Sun is Saturn. Saturn is a member of the "gas giants". Saturn is mostly known for its series of rings although there are many more interesting facts about this most beautiful planet.
Until the invention of the telescope, Saturn was thought to be the farthest planet from the Sun. Saturn is twice as far out as Jupiter, and ten times furthur from the Sun than Earth. Saturn is so far away that the Sun appears as a bright point of light, rather than a small disk like the closer planets. The second largest planet, behind Jupiter, has only one-third the mass of Jupiter. Remarkably, along with a low mass for its size, Saturn's density is so low that it would float if placed in water.
Saturn's elliptical orbit takes it 29 Earth years to travel once around the Sun. One day on Saturn is 10.5 hous long. Saturn's day is short because of its extremely fast spin. This fast spin causes the equator of Saturn to bulge out. This makes the diameter at the equater longer than between its poles.
So far, we have only seen the thick cloud layer surrounding Saturn. It is the lower and heavier clouds that prevent us from seeing farther inside the planet. Although we have not explored the planet, we can still hypothesize on its conditions and compostion.
Results from estimates indicate that Saturn has a hard core made of rock and ice.This core amounts for one-quater of the planets entire mass.The next layer up, surrounding the core, is a layer of densely packed hydrogen that has become a liquid metal. Above this is a layer composed of hydrogen molecules that are in a form of a liquid but at a greater height become gas.The interior of Saturn is extremely hot. It heats the planet more than the Sun does. This heat is caused by the mixing of helium with the hydrogen in the lower layers.The helium mixes with the hydrogen gas and then condenses with the metalic hydrogen and then falls like rain, which gives off heat in the process. During this process, a magnetic field is also produced throughout the planet.
Because there is no surface crust on Saturn, there is no definite boundary between the atmosphere and the rest of the planet. Therefore, it doesn't really have an atmosphere. The atmosphere of Saturn can be thought of as the colored clouds that band around the planet parrallel to the equator. The top layer of these clouds cantains particles of ammonia, and appears white with holes of brown and blue that occasionally appear and reveal deeper layers. At this blue layer, the temperature is about the same as the lower atmosphere of Earth.
Saturn has weather that is mostly caused by the rising heat and sunlight. This weather would be considered very violent by our standards. Winds on Saturn can reach up to 1,000 miles(1,600 km) per hour, near the equater and blowing east. Storms on Saturn can last more than a year. These storms appear as oval spots in the bands.
Saturn's rings are unmatched by any other planet. The rings of Saturn lie in the same plane as the equator and are quite thin. Thin enough that stars can be seen through them. The rings can be seen at all times except when they are edge-on to Earth, whence they disapear, but this only happens every fifteen years.
The rings of Saturn are not solid like they look. They are made up of countless small, separate particles of rock and ice that circle the planet. There are seven major rings. They are called by letters: A-G, and there order is confusing because of there time of discovery.
DISTANCE FROM SATURN'S CENTER
|Cloud Top||37,500 miles (60,300 km)|
|D, inner edge||41,500 miles (66,300 km)|
|C, inner edge||46,100 miles 74,200 km)|
|B, inner edge||57,000 miles (92,000 km)|
|B, outer edge||73,000 miles (117,000 km)|
|A, inner edge||75,800 miles (122,000 km)|
|Encke Gap||82,900 miles (133,400 km)|
|A, outer edge||84,900 miles (136,600 km)|
|F||87,300 miles (140,500 km)|
|G||106,000 miles (171,000 km)|
|E, inner edge||130,000 miles (209,000 km)|
The rings continue to be examined. When the two Voyager spacecraft photographed the rings they solved many problems and answered many questions. But they brought up new problems and questions. Such as: some of the rings are made up of thousands of small ringlets made of icy dust, while there are others made up of huge boulders, some rings are circular, while others are elliptical, and there are mysterious "spokes" that cross the B ring.
Saturn has 17 known moons. This is the most known to orbit any planet. These moons range from Titan,bigger than Mercury, to smaller moonlets less than 20 miles (32 km) across. Many of the moons have irregular shapes. This can be explained by gravity. Objects larger than 200 miles (320 km) have gravity strong enough to pull matter as close together as possible, while objects smaller than 200 miles (320 km) do not have a strong enough gravity to be sphereical. The moons orbits can be as short as 14 hours to as long as a one and a half years.
Distance in miles (km)
|Phoebe*||140 miles (225 km)||8,049,200 (12,954,000)||13,210.8|
|Iapetus||910 miles (1,465km)||2,212,600 (12,954,000)||1,903.94|
|Hyperion*||255 miles (410 km)||920,200 (1,480,900)||510.64|
|Titan||3,200 miles (5,150km)||759,230 (1,221,900)||382.69|
|Rhea||950 miles (1,530km)||327,520 (527,090)||108.42|
|Helene*||22 miles (35 km)||234,920 (378,070)||65.74|
|Dione||700 miles (1,127km)||234,520 (377,420)||65.69|
|Calypso*||21 miles (34 km)||183,100 (294, 670)||45.31|
|Telesto*||21 miles (34 km)||183,100 (294,670)||45.31|
|Tethys||660 miles (1,062 km)||183,100 (294,670)||45.31|
|Enceladus||310 miles (499 km)||147,910 (238,040)||32.88|
|Mimas||244 miles (393 km)||115,290 (185,540)||22.62|
|Epimetheus*||135 miles (217 km)||94,120 (151,470)||16.67|
|Janus*||85 miles (137 km)||94,089 (151,420)||16.66|
|Pandora*||70 miles (113 km)||88,050 (141,700)||15.08|
|Prometheus*||85 miles (137 km)||86,590 (139,300)||14.71|
|Atlas*||25 miles (40 km)||85,540 (137,600)||14.45|
NOTE: All moons with * are not sphereical. Their longest diameter is their given value.
SATURN'S SPHEREICAL MOONS
This sphereical moon is the smallest and closest to Saturn of the sphereical moons. Mimas orbits just within the ring system. Saturn looks enormous to Mimas and because of its short orbit, Saturn changes from a ball to a cresent to a ball frequently. Mimas is locked in its orbit tidally, like our Moon, and always has the same side facing Saturn. Mimas is mostly known for its giant 80-mile (128-km) wide crater on this face called Herschel.
Tethys is a middle-sized moon of Saturn that is much larger than Mimas and orbits the planet in less than two days. Tethys is made up of ice with some rocky materials. Tethys is known for its craters which cover its entire surface. It contains the largest known crater in the solar system, Odysseus which is 250 miles (400 km) across. A large valley runs three-quaters across the moon that might be a crack caused by the collision that formed Odysseus. The two smallest satellites of Saturn, Calypso anf Telepso, have the same orbit as Tethys.
Outward from Tethys is Dione. Dione can be considered Tethys' sister moon. It is nearly the same size and shape. It is composed of streaks of bright ice and dark rocks.
The second largest of Saturn's moons has a surface battered by craters. It takes Rhea four and one-half days to orbit Saturn. Rhea's orbital plane is the same as the ring system, resulting in the rings always seen edge-on. Ice and some rock make up Rhea, with a density greater than water. Rhea also has a locked orbit, with one side always facing the planet. Rhea is known for its interesting variations in color.
Titan is the largest moon of Saturn and is larger than the planet Mercury and also Pluto. It is the only moon in the solar system that has an atmosphere and it is thought that it has the capability to support life. It takes Titan 16 days to complete its orbit of Saturn. Titans plane is nearly the same as Saturn's ring so the ring also appear edge-on. Titan is most likely composed of one-half ice and one-half rock, with most of the rock in the core.
Iapetus is the farthest out of the sphereical moons of Saturn. It is made up of mainly ice and always has the same side facing Saturn. Its orbit is at a tilt of 15š to the rings and it takes Iapetus 79 days to orbit Saturn. Oddly, one side of Iapetus is much brighter than the other, probably caused by ice compostion. Iapetus' surface has many impact craters.
Diameter . . . . . . . . . . . . . . . . . .75,000 miles (120,000 km)
Mass . . . . . . . . . . . . . . . . . . . . 95 times that of Earth
Distance from the Sun. . . . . . . . . 886 million miles (1,426 million km)
Rotation Period . . . . . . . . . . . . . 10.5 hours
Tilt of Axis . . . . . . . . . . . . . . . .26.73š
Temperature at Cloudtops. . . . . . -310šF (-190šC)
Atmosphere Compostion . . . . . . hydrogen, helium
Known Moons. . . . . . . . . . . . . 17