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

Missions to Saturn:

 -  
Pioneer 11 in September 1979

-
  Voyager 1 in November 1980
-  Voyager 2 in August 1981

 - Cassini–Huygens spacecraft in July 1, 2004



Saturn in History: 

Because is visible whit the naked eye, Saturn was known from ancient times:


Babylonian astronomers systematically observed and recorded the movements of Saturn. In Roman mythology, the god Saturnus, from whici the planet takes its name, was the god of agricultural and harvest sector. They considered Saturnus the equivalent of  the Greek god Cronus so as usual Greeks associates a particular star whit a god and the Romans followed suit.


In Hindu astrology, Saturn is known as "Shani", the one that judges everyone based on the good and bad deeds performed in life. In the 5th century CE, the Indian astronomical text Surya Siddhanta estimated the diameter of Saturn whit a remarkable precision by more then 99%. Ancient Chinese and Japanese designated the planet Saturn as the earth star, based on the Five Elements which were traditionally used to classify natural elements.

In Hebrew, Saturn is called "Shabbathai" and in ottoman Turkish, Urdu and Malay, its name is "Zuhal", derived from Arabic.

European observations (17th–19th centuries):
Galileo was first to saw the ring as two moons on Saturn's sides and only when Christian Huygens used greater telescopic magnification this notion was refuted. Huygens was also the one ho discovered Saturn's moon Titan. Giovanni Domenico Cassini discovered four other moons: Iapetus, Rhea, Tethys and Dione. He also discovered the gap now known as the Cassini Division.

Almost 150 ears later William Herschel discovered two further moons, Mimas and Enceladus.

And in 1899 William Henry Pickering discovered Phoebe, a highly irregular satellite that does not rotate synchronously with Saturn as the larger moons do. Phoebe was the first such satellite found and it takes more than a year to orbit Saturn in a retrograde orbit. During the early 20th century, research on Titan led to the confirmation in 1944 that it had a thick atmosphere, a feature unique among the solar system's moons.


Saturn internal structure: 


Saturn's internal structure is similar to that of Jupiter, having a small rocky core surrounded mostly by hydrogen and helium. The rocky core is similar in composition to the Earth, but much more dense. Core is surrounded by a thicker liquid metallic hydrogen layer, followed by a liquid hydrogen/helium layer and a gaseous region is estimated to be about 9-22 times the mass of the Earth. The temperature of Saturn's core is about 11,700  °C and radiates 2.5 times more energy into space than it receives from the Sun. Most of this extra energy is generated by the Kelvin - Helmholtz mechanism (slow gravitational compression), but this alone may not be sufficient to explain Saturn's heat production. It is possibely that an additional mechanism might be at play whereby Saturn generates some of its heat through the "raining out" of droplets of helium deep in its interior, thus releasing heat by friction as they fall down through the lighter hydrogen. The interior is estimated to be about 25,000 km across.



Saturn atmosphere:


Saturn has an outer atmosphere of 96.3% molecular hydrogen and 3.25% helium. Also have been detected trace amounts of ammonia, acetylene, ethane, phosphine and methane.
The upper clouds on Saturn are made of ammonia crystals, while the lower level clouds apper to be composed of either ammonium hydrosulfide or water. The atmosphere of Saturn is significantly deficient in helium relative to abundance of the elements in the Sun.

Rings of Saturn:




Saturn is best known for its planetary ring, which makes it the most visually remarkable object in the solar system. The rings extend from 6,600 km to 120,700 km above Saturn's equator.
Composition of the rings is a 93$ water ice with a smattering of thlion impurities and 7% amorphous carbon. The particles that make up the ring range in size from specks of dust up to 10m..
There are two main theories about the formation of the rings. One of them is that the rings are remnants of a destroyed moon of Saturn and the second theory is that the rings are left over from the original nebula material from which Saturn formed. Some ice in the central rings comes from the moon Enceladus' ice volcanoes.


Beyond the main rings at a distance of 12 million km from the planet is the spare Phoebe ring, which is tilted at an angle of 27°  to the other rings and like Phoebe, orbits in retrograde fashion. Some of the moons of Saturn act as shepherd moons to keep the planetary ring stable and prevent them from escaping. Pan and Atlas, two of Saturn moons, cause weak, linear density waves in Saturn's rings that have yielded more reliable calculations of their masses.


The age of these planetary rings is probably hundreds of millions of years old (in contrast to previous thoughts that the rings formed alongside the planet when it formed billions of years ago) and their fate include spiraling inward towards the planet, or the boulders forming the rings colliding with each other and disappearing.





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