Saturn
sixth planet from the Sun and the second-largest planet in the Solar System, after Jupiter / From Wikipedia, the free encyclopedia
Saturn is the sixth planet from the Sun in the Solar System.
Designations | |||||||||||||
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Pronunciation | /ˈsætərn/ (listen)[1] | ||||||||||||
Named after | Saturn | ||||||||||||
Adjectives | Saturnian /səˈtɜːrniən/,[2] Cronian[3] / Kronian[4] /ˈkroʊniən/[5] | ||||||||||||
Orbital characteristics[6] | |||||||||||||
Epoch J2000.0 | |||||||||||||
Aphelion | 1,514.50 million km (10.1238 AU) | ||||||||||||
Perihelion | 1,352.55 million km (9.0412 AU) | ||||||||||||
1,433.53 million km (9.5826 AU) | |||||||||||||
Eccentricity | 0.0565 | ||||||||||||
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378.09 days | |||||||||||||
Average orbital speed | 9.68 km/s (6.01 mi/s) | ||||||||||||
317.020°[8] | |||||||||||||
Inclination | |||||||||||||
113.665° | |||||||||||||
2032-Nov-29[10] | |||||||||||||
339.392°[8] | |||||||||||||
Known satellites | 145 in total moonlets.[6] | ||||||||||||
Physical characteristics[6] | |||||||||||||
Mean radius | 58,232 km (36,184 mi)[lower-alpha 1] | ||||||||||||
Equatorial radius |
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Polar radius |
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Flattening | 0.09796 | ||||||||||||
Circumference |
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Volume |
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Mass |
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Mean density | 0.687 g/cm3 (0.0248 lb/cu in)[lower-alpha 2] (less than water) | ||||||||||||
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0.22[13] | |||||||||||||
35.5 km/s (22.1 mi/s)[lower-alpha 1] | |||||||||||||
10 h 32 m 36 s (synodic; solar day)[7] | |||||||||||||
Sidereal rotation period | 10h 33m 38s + 1m 52s − 1m 19s [14][15] | ||||||||||||
Equatorial rotation velocity | 9.87 km/s (6.13 mi/s; 35,500 km/h)[lower-alpha 1] | ||||||||||||
26.73° (to orbit) | |||||||||||||
North pole right ascension | 40.589°; 2h 42m 21s | ||||||||||||
North pole declination | 83.537° | ||||||||||||
Albedo | |||||||||||||
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−0.55[20] to +1.17[20] | |||||||||||||
14.5″ to 20.1″ (excludes rings) | |||||||||||||
Atmosphere[6] | |||||||||||||
Surface pressure | 140 kPa[21] | ||||||||||||
59.5 km (37.0 mi) | |||||||||||||
Composition by volume |
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Saturn is one of the four gas giant planets in the Solar System, with Jupiter, Uranus, and Neptune. It is the second largest planet in the Solar System (Jupiter is the largest).[22]
Saturn was named after the Roman god Saturn. He was the Roman equivalent of the Greek god Kronos.[23] Saturn's symbol is ♄ which is the symbol of Saturnus' sickle.[24]
Inside Saturn is probably a core of iron, nickel, silicon and oxygen compounds, surrounded by a deep layer of metallic hydrogen, then a layer of liquid hydrogen and liquid helium and finally, an outer gaseous layer.[25]
Saturn has 146 known moons orbiting the planet.[26] The largest moon is Titan. Titan is larger in volume than the planet Mercury. It is the second-largest moon in the Solar System. The largest moon is a moon of Jupiter, Ganymede. There are also many rings around Saturn. These rings are made of ice with some rocks and dust. Some people think that that the rings were made by a moon impact or other event. Saturn is about 1,433,000,000 km (870,000,000 mi) on average from the Sun. Saturn takes 29.4 Earth years in order to complete a revolution around the Sun.[27]