Saturn( sol planet)

**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

## Physical characteristics

aturn 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.
stronomers 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

Since Saturn does not rotate on its axis at a uniform rate, multiple rotation periods have been assigned to it (as in Jupiter's case): *System I* has a period of 10 h 14 min 00 s (844.3°/d) and encompasses the Equatorial Zone, which extends from the northern edge of the South Equatorial Belt to the southern edge of the North Equatorial Belt. All other Saturnian latitudes have been assigned a rotation period of 10 h 39 min 24 s (810.76°/d), which is *System II*. *System III*, based on radio emissions from the planet, has a period of 10 h 39 min 22.4 s (810.8°/d); because it is very close to System II, it has largely superseded it.

While approaching Saturn in 2004, the Cassini spacecraft found that the radio rotation period of Saturn had increased slightly, to approximately 10 h 45 m 45 s (± 36 s).[10] The cause of the change is unknown — however, it is thought that this is due to a movement of the radio source to a different latitude inside Saturn, with a different rotational period, rather than an actual change in Saturn's rotation.

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

### Historyedit | edit source

The rings were first observed by Galileo Galilei in 1610 with his telescope, but he was unable to identify them as such. He wrote to the Duke of Tuscany that "The planet Saturn is not alone, but is composed of three, which almost touch one another and never move nor change with respect to one another. They are arranged in a line parallel to the zodiac, and the middle one (Saturn itself) is about three times the size of the lateral ones [the edges of the rings]." He also described Saturn as having "ears." In 1612 the plane of the rings was oriented directly at the Earth and the rings appeared to vanish, and then in 1613 they reappeared again, further confusing Galileo.[12]

In 1655, Christiaan Huygens became the first person to suggest that Saturn was surrounded by a ring. Using a telescope that was far superior to those available to Galileo, Huygens observed Saturn and wrote that "It [Saturn] is surrounded by a thin, flat, ring, nowhere touching, inclined to the ecliptic."[13]

In 1675, Giovanni Domenico Cassini determined that Saturn's ring was actually composed of multiple smaller rings with gaps between them; the largest of these gaps was later named the Cassini Division.

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.