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10 759.22 days per year
378.09 Earth days per one Saturn day
Distance from Sun:
1,433,449,370 km
2.485 240° to Ecliptic, 5.51° to Sun's equator, 0.93° to invariable plane
120,536 km (equatorial), 108,728 km (polar)
1.07 g
hydrogen, helium, methane, ammonia, hydrogen deuteride, ethane, water

Saturn (IPA: [ˈsæɾɚn], [ˈsætən]) is the sixth planet from the Sun. It is a gas giant (also known as a Jovian planet, after the planet Jupiter), the second-largest planet in the Solar System after Jupiter. Saturn has a prominent system of rings, consisting mostly of ice particles with a smaller amount of rocky debris and dust. It was named after the Roman God Saturn (the Greek mythology equivalent is Kronos, father of Zeus). Its symbol is a stylized representation of the god's sickle (Unicode: ).[1][2]

Physical characteristics

Saturn polar vortex

Saturn's temperature emissions: The prominent hot spot at the bottom of the image is at Saturn's south pole.



Saturn, Earth size comparison

Visual comparison of Saturn and Earth


Saturn has hidden similarities to Jupiter, mainly due to its banded atmosphere. But the bands are usually hidden by a haze of ammonia. Every 30 years, a large, white oval appears. These ovals are Great White Spots, large storms with lightning which can cover the whole planet within a matter of weeks, like the 2010/11 storm. Another notable feature is a vast lightning storm in Saturn's southern hemisphere called the Dragon Storm. The Dragon Storm is large enough to engulf the largest of the Earth's continents and produces lightning thousands of times more powerful than storms on Earth. Saturn also contains one of the highest winds in the Solar System, capable of reaching 1,120 mph (1,800 km/h). In recent images from the Cassini spacecraft, Saturn's northern hemisphere appears a bright blue, similar to Uranus, as can be seen in the image above. This blue color cannot currently be observed from Earth, because Saturn's rings are currently blocking its northern hemisphere. The color is most likely caused by Rayleigh scattering.

Saturn hexagonal north pole feature

North polar hexagonal cloud feature, discovered by Voyager 1 and confirmed in 2006 by Cassini. [1] [2]

Astronomers using infrared imaging have shown that Saturn has a warm polar vortex, and is the only such planet known in the solar system.

A persisting hexagonal wave pattern around the north polar vortex in the atmosphere at about 78°N was first noted in the Voyager images.[3][4] Unlike the north pole, HST imaging of the south polar region indicates the presence of a jet stream, but no strong polar vortex nor any hexagonal standing wave.[5] However, NASA reported in November 2006 that the Cassini spacecraft observed a 'hurricane-like' storm locked to the south pole that had a clearly defined eyewall.[6] This observation is particularly notable because eyewall clouds have not been seen on any planet other than Earth (including a failure to observe an eyewall in the Great Red Spot of Jupiter by the Galileo spacecraft).[7]

The straight sides of the northern polar hexagon are each about 13,800 kilometers long. The entire structure rotates with a period of 10h 39m 24s, the same period as that of the planet's radio emissions, which is assumed to be equal to the period of rotation of Saturn's interior. The hexagonal feature does not shift in longitude like the other clouds in the visible atmosphere.

The pattern's origin is a matter of much speculation. Most astronomers seem to favor some sort of standing-wave pattern in the atmosphere; but the hexagon might be a novel sort of aurora. More extreme speculation has Saturn's radio emissions emanating from the hexagon (something we can see and which has the right rotation period) rather than from the planet's interior (something we cannot see).[8] Polygon shapes have been replicated in spinning buckets of fluid on laboratory scales.[9]

Rotational behavior


Animated gif of hexagonal cloud feature.



In March of 2007 it was reported that the variance in measured rotation periods may actually be caused by geyser activity on Saturn's moon Enceladus. The water vapor emitted into Saturnian orbit by this activity becomes charged and "weighs down" Saturn's magnetic field, slowing its rotation slightly relative to the rotation of the planet itself. If true, this means that there is no currently known method of determining the actual rotation rate of Saturn's core.[11]

Planetary rings

Saturn from Cassini Orbiter (2007-01-19)

The rings of Saturn, as imaged by Cassini in 2007

Main article: Rings of Saturn

Saturn is probably best known for its system of planetary rings, which makes it one of the most visually remarkable objects in the solar system.





In 1859, James Clerk Maxwell demonstrated that the rings could not be solid or they would become unstable and break apart. He proposed that the rings must be composed of numerous small particles, all independently orbiting Saturn.[14] Maxwell's theory was proven correct in 1895 through spectroscopic studies of the rings carried out by James Keeler of Lick Observatory.

Physical characteristics


Saturn's rings cut across an eerie scene that is ruled by Titan's luminous crescent and globe-encircling haze, broken by the small moon Enceladus, whose cryovolcanos are dimly visible at its south pole. North is up.







Two storms are currently raging on Saturn dubbed the Dragon Storm and the Great White Spot.

Spokes of the rings

Voyager ring spokes

Spokes in the B ring, imaged by Voyager 2 in 1981


H cassini spokes 02

Spokes imaged by Cassini in 2005


Natural satellites

Main article: Saturn's natural satellites
Four Saturnian moons PIA07644

Four of Saturn's moons: Dione, Titan, Prometheus (edge of rings), Telesto (top center)

Saturn has a large number of moons. The precise figure is uncertain, as the orbiting chunks of ice in Saturn's rings are all technically moons, and it is difficult to draw a distinction between a large ring particle and a tiny moon. As of 2007, a total of 57 individual moons have been identified, plus 3 unconfirmed moons that could be small dust clumps in the rings. Many of the moons are very small: out of 57, 31 are less than 10 km in diameter, and another 13 less than 50 km.[18] Only seven of them are massive enough to have collapsed into spheroids under their own gravitation. These are compared with Earth's moon in the table below. Saturn's most noteworthy moon is Titan, the only moon in the solar system to have a dense atmosphere.

Traditionally, most of Saturn's other moons are named after actual Titans of Greek mythology. This started because John Herschel — son of William Herschel, discoverer of Mimas and Enceladus — suggested doing so in his 1847 publication Results of Astronomical Observations made at the Cape of Good Hope[19], because they were the sisters and brothers of Cronos (the Greek Saturn).

Saturn's major satellites, compared with Earth's Moon.

(Pronunciation key)

Orbital radius (km) Orbital period (days)
Mimas ˈmaɪməs 400
(10% Luna)
(0.05% Luna)
(50% Luna)
(3% Luna)
Enceladus ɛnˈsɛləɾəs 500
(15% Luna)
(0.2% Luna)
(60% Luna)
(5% Luna)
Tethys ˈtʰiθɪs 1060
(30% Luna)
(0.8% Luna)
(80% Luna)
(7% Luna)
Dione daɪˈəʊni 1120
(30% Luna)
(1.5% Luna)
(100% Luna)
(10% Luna)
Rhea ˈriə 1530
(45% Luna)
(3% Luna)
(140% Luna)
(20% Luna)
Titan ˈtʰaɪʔən 5150
(150% Luna)
(180% Luna)
(320% Luna)
(60% Luna)
Iapetus aɪˈæpəɾəs 1440
(40% Luna)
(3% Luna)
(930% Luna)
(290% Luna)

Exploration of Saturn

Saturn&#039;s rings

A Hubble Space Telescope image, captured in October 1996, shows Saturn's rings from just past edge-on. Credit: NASA/ESA.

Pioneer 11 flyby


Voyager flybys




Cassini orbiter

Saturn eclipse

Saturn eclipses the sun, as seen from Cassini.


The orbiter completed two Titan flybys before releasing the Huygens probe on December 25 2004. Huygens descended onto the surface of Titan on January 14 2005, sending a flood of data during the atmospheric descent and after the landing. During 2005 Cassini conducted multiple flybys of Titan and icy satellites.

On March 10 2006, NASA reported that the Cassini probe found evidence of liquid water reservoirs that erupt in geysers on Saturn's moon Enceladus.[21]

On September 20 2006, a Cassini probe photograph revealed a previously undiscovered planetary ring, outside the brighter main rings of Saturn and inside the G and E rings.[22]


As of 2006 the probe has discovered and confirmed 4 new satellites. Its primary mission will end in 2008 when the spacecraft will be expected to have completed 74 orbits around the planet.

For the latest information and news releases, see Cassini website.


Best viewing of Saturn


Saturn Oppositions: 2001-2029

Saturn has been known since prehistoric times. It is the most distant of the five planets easily visible to the naked eye, the other four being Mercury, Venus, Mars, and Jupiter (Uranus is visible to the naked eye in very dark skies), and was the last planet known to early astronomers until Uranus was discovered in 1781. Saturn appears to the naked eye in the night sky as a bright, yellowish star varying usually between magnitude +1 and 0 and takes approximately 29½ years to make a complete circuit of the ecliptic against the background constellations of the zodiac. Optical aid (large binoculars or a telescope) magnifying at least 20X is required to clearly resolve Saturn's rings for most people.


Saturn in various cultures

In Hindu astrology, there are nine planets, known as Navagrahas. Saturn is known as "Sani" or "Shani", the Judge among all the planets, and determines everyone according to their own performed deeds bad or good.

Chinese and Japanese culture designate the planet Saturn as the earth star (土星). This is based on Five Elements which were traditionally used to classify natural elements.


In Ottoman Turkish and in Malay, its name is 'Zuhal', derived from Arabic زحل.

Saturn was also called Φαίνων, Phainon ("shiner") by the Greeks.

See also



  2. Crystal, Ellie. Saturn Mythology. Retrieved on 2007-02-28.
  6. NASA catalog page for image PIA09187
  7. NASA Sees into the Eye of a Monster Storm on Saturn. NASA (2006-11-09). Retrieved on November 10, 2006.
  8. A Hex on Saturn. Science Frontiers (1989-5-31). Retrieved on March 28, 2007.
  10. Scientists Find That Saturn's Rotation Period is a Puzzle. NASA (06.28.04). Retrieved on 2007-03-22.
  11. Template:Cite press release
  22. New Ring Spotted Around Saturn – Article on
  23. Probe spots seas on Saturn's moon Titan - CNN article.

External links

 The Solar System v·d·e 
Solar System XXVII
Pluto' * Ceres * Eris * Haumea * Makemake

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