Saturn, the second largest planet in our Solar System is sixth planet from the Sun. Just like Mercury, Venus, Mars and Jupiter, Saturn is also visible from Earth with the naked-eye. Galileo was the first to observe it with a telescope in 1610 and was the first to observe Saturn’s complex ring system. Many other planets like Jupiter, Uranus and Neptune also have ring systems, but they are neither as extensive nor brilliant. Although the origin of these great rings is unidentified, scientists look forward to learn more through studying the planet’s history with the help of space probes like Cassini.
Saturn’s Atmosphere
Saturn is similar to Jupiter, however it is much smaller. Just like Jupiter, Saturn is a gaseous planet. Alternate jet streams of east-west and west-east circulation can be seen in the motions of the cloud tops. The speed of these jet streams sometimes reaches to hundreds of metres per second. Hydrogen and helium constitute the majority of the atmosphere; however it also includes trace amounts of other elements. Electrical processes and heat starting from the internal planetary sources enhance the chemical mixture of the atmosphere. Saturn’s atmosphere also features large storm structures like Jupiter’s famous Great Red Spot.
The wind blows at very high speeds on Saturn. Near the equator, it attains velocities of 500 meters a second. The wind blows mostly in an easterly direction. The strongest winds occur near the equator and velocity falls off evenly at higher latitudes. At latitudes more than 35 degrees, winds alternate east and west as latitude increases.
Saturn’s Density
Saturn is the planet with the least density in our Solar System. Mostly it is made up of hydrogen and helium, which are the two lightest elements in the universe and therefore make Saturn the lightest planet. And since Saturn is so light, it does not have as much gravity as other planets. Because of its lightweight the planet spins very fast.
Saturn is not round like the majority of other planets. Similar to Jupiter, Saturn is wider in the middle and narrower near its top and bottom. Its equatorial and polar diameters differ by almost 10% (120,536 km vs. 108,728 km). This is the because of its rapid rotation and fluid state.
Interior of Saturn
Under the clouds of hydrogen and helium, the atmosphere slowly turns into liquid until it becomes a giant ocean of liquid chemicals. Saturn’s interior is similar to Jupiter’s having a rocky core, a liquid metallic hydrogen layer and a molecular hydrogen layer. Traces of various ices are also there. Saturn’s interior is very hot. It is about 12,000 C at the core and the planet gives out more energy into space than it gets from the Sun.
Saturn’s Rings
Saturn is well known for its rings. Saturn’s rings are very beautiful and are approximately 169,800 miles wide. However these rings are amazingly thin. The rings are not solid, however, they are made up of particles of ice, dust and rocks. Saturn has 7 major ring divisions – Ring A, Ring B, Ring C, Ring D, Ring E, Ring F and Ring G. Rings A and B and one faint ring C can be observed from the Earth. The space between rings A and B is known as the Cassini division. Saturn’s rings, unlike the rings of other planets, are very bright.
Saturn’s outermost ring, the F-ring, is a complex structure made up of a number of smaller rings along with the visible “knots”. Scientists presume that the knots may be bunches of ring material, or mini moons. The rings are held in place around Saturn by the moons which also orbit this large planet. The gravity of these moons also results in the gaps that are seen in between the rings.
Moons of Saturn
Saturn has 18 major moons. However, this number is increasing as more and more get discovered. The newer moons are generally very small and of minor importance. Titan is Saturn’s best-known moon. It is Saturn’s largest moon and second largest moon in the Solar System next to Jupiter’s Ganymede. Titan is even larger than Mercury. It is covered by a thick nitrogen atmosphere, which might be like what Earth’s atmosphere was billions of years ago. More study of this moon assures to reveal interesting information about planetary formation and maybe regarding the primordial Earth as well.
Saturn’s second largest moon, Rhea, may have a small ring system of its own. The other moons are very small: 34 are under 10 km in diameter and another 14 under 50 km.
Missions to Saturn
Saturn was first visited by NASA’s Pioneer 11 in 1979 and afterwards by Voyager 1 and Voyager 2. After this in October 1997, Cassini, a joint U.S-European orbiter/probe mission to Saturn and Titan, was launched. On July 1, 2004, the Cassini–Huygens space probe carried out the Saturn Orbit Insertion maneuver and entered into orbit around Saturn. Cassini images offered evidence of hydrocarbon lakes near Titan’s North Pole. Other images near Titan’s north pole discovered hydrocarbon “seas”, the largest of which is almost the size of the Caspian Sea. In October 2006, the probe detected a 8,000 km diameter hurricane with an eye wall at Saturn’s South Pole. From 2004 to November 2, 2009, the probe discovered and confirmed 8 new satellites. Its primary mission ended in 2008 when the spacecraft had completed 74 orbits around the planet. The probe’s mission was extended to September 2010 and then extended again to 2017, to study a full period of Saturn’s seasons.
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[Images: www.nasa.org]
