Saturn An Overview - Article Example

30 November Saturn – An Overview Saturn is the sixth planet of the solar system and is at a distance of around 1.4 billion km from the sun (NASA para i). Galileo Galilei, an Italian astronomer, was the first to gaze at the planet through a telescope in 1610. Seeing a pair of objects the planets sides, he sketched them as spheres assuming that Saturn had three bodies as a whole. He also sketched handles or arms attached to the planet. Later on in 1659, Christiaan Huygens, a Dutch astronomer proposed that Saturn was surrounded by a flat ring. Several years later in 1675, Italian astronomer Jean-Dominique Cassini found the presence of a division in the ring, which are now called A and B rings. This division in the ring is caused by the gravitational influence of Mimas, one of Saturn’s moons. The planet Saturn is named after the Roman god of agriculture and in Greek, it was called Cronos, after the father of Jupiter/Zeus (NASA para vii). Saturn is the farthest planet that can be observed by the human eye without a telescope (NASA para i). Composition Saturn is a gaseous planet made of helium and hydrogen. It has a volume 755 times higher than the earth. The winds in its upper atmosphere in the equatorial region reach up to 500 meters per second. Comparatively, on Earth, the strongest hurricanes reach only up to 110 meters per second maximum. Saturn has golden and yellow bands in its atmosphere that result from the combination of high-speed winds combined with heat from the planet’s interior (NASA para iii). The atmosphere of Saturn has persistent oval cloud features similar to that on Jupiter (Smith et al. 504). A zonal wind pattern has also been pictured by Voyager 2 spacecraft which spreads out symmetrically at the planet’s equator and seems to extend quite deep into the planet (Smith et al. 504). Facts Saturn takes 10.7 hours for one rotation, implying that one day at Saturn lasts only 10.7 hours. It takes 29 Earth years to make one orbit around the sun. Until date, five missions have been sent to Saturn, with Cassini (the last one) exploring the planet since 2004. The planet has 53 known moons with nine more waiting to be listed after their discovery. The planet has a spectacular ring system, make up of seven rings with several divisions between them (NASA para i). Saturn’s Moons While the four moons of planet Jupiter clearly seem to be related to one another and formed with Jupiter, in case of Saturn’s satellites, such a relationship has not been found (Seeds and Backman 527). Therefore, unlike Jupiter, it is indicated that Saturn did not serve as a heat source during the formation of that system to cause the moons’ densities to follow a condensation sequence. Scientists also alternatively speculate that impacts of comets have badly fractured the moons to such an extent that they do not show evidence that they had a common origin. Therefore, understanding the origin of Saturn’s moons is difficult. In addition, the orbits of the moons may be different from their earlier orbits because of their gravitational interaction, making it even more difficult to understand their origins (Seeds and Backman 527). As NASA puts it, “Saturn, the sixth planet from the sun, is home to a vast array of intriguing and unique worlds. From the cloud-shrouded surface of Titan to crater-riddled Phoebe, each of Saturns moons tells another piece of the story surrounding the Saturn system” (3). The first known moon of the planet, named Titan, was discovered by Christiaan Huygens in 1655. The next four moons to be discovered were Iapetus, Rhea, Dione, and Tethys, by Giovanni Domenico Cassini between 1671 and 1684. William Herschel discovered Enceladus and Mimas in 1789 and more than fifty years later, Hyperion and Phoebe were discovered. As technological advancements took place, more and more moons were discovered. A total of fifty three moons of Saturn are now known. Some of the moons interact with the ring material of the planet and some small moons are trapped in single orbits. Two of its moons, Epimetheus and Janus, are known to exchange orbits periodically as they pass very close to each other. Saturn’s largest moon, Titan, is so large that the orbits of other moons close-by are affected by it. It is also the second largest moon in our solar system. The moon’s surface is hidden by a thick atmosphere rich in nitrogen. It present atmosphere is similar to previous atmosphere of the Earth, before Earth became conducive to biological life. The atmosphere of Titan is made of traces of methane and 95% nitrogen (NASA 3). Saturn’s Rings Saturn has a spectacular ring system. Describing the beauty of it, one astronomer wrote, “The rings are made of beautiful physics” (qtd. in Seeds and Backman 527). The first to see Saturn’s rings was Galileo Galilei in 1610. Christiaan Huygens later found that the rings form a disk that surrounds but does not touch the planet. Studies suggest that the rings are made of ice particles, each of which is in its own orbit around the planet. It is speculated that these rings were not present during the time of formation of the planet. The rings are occasionally replenished through impacts on the planet’s icy moons or when a moon moving very close to the planet disrupts. Gravitational effects of ‘shepherd satellites’, the name given to Saturn’s small moons, may result in the confinement of certain rings in narrow strands or in the maintenance of sharp edges of the rings. Waves produced by the moons in the planet’s rings could also be visible as ringlets that are tightly wound. The ring particles at the equatorial plane of Saturn do not spread outward due to the gravitational forces of the small moons. Gravitational interactions of larger and more distant moons in turn control the small moons. Like other Jovian planets, the rings of Saturn are created from and controlled by its moons and without the moons, the rings would not have existed (Seeds and Backman 527). Figure 1: B and C rings of Saturn in image taken by Voyager 2 spacecraft (Hofer 25) Michael had reported the presence of ring particles in the planet’s main rings which spin slowly, are relatively large, and have thermal inertia low enough to support a rapid thermal response (n.p.). Advanced research on the rings has shown the occurrence of various other processes. For instance, it is now known that specks of dust on the rings are electrically charged by sunlight and are lifted by Saturn’s magnetic field out of the ring plane. Scallops, gaps and waves are produced in the rings by small moonlets embedded in them (Seeds and Backman 527). Studies such as those by Sagan, Khare and Lewis investigated the presence of organic matter in the planet’s system (788). Spectral data of Voyager IRIS confirmed the presence of organic molecules heavier than CH4, including acetylene, alkanes, alkynes, butadiene, cyanoacetylene, cyanogens, ethane, ethylene, hydrogen cyanide, methylacetylene, nitriles and propane. These findings are of significance because the processes and organic molecules found within the atmosphere of Titan may have had analogs in the atmosphere of early Earth, about 4 gigayears ago (Sagan, Khare and Lewis 788). This might mean that there are chances of evolution of biological life on Titan similar to what has happened on planet Earth. Pioneer 11, Voyager 1, Voyager 2, and Huygens are the missions that previously explord Saturn. Cassini is NASA’s current mission to Saturn. Works Cited Hofer, Charles. Saturn. New York: The Rosen Publishing Group, 2008. Michael, Flasar. “Saturn and Its Satellites and Rings Viewed through the Infrared Eyes of Cassini CIRS.” EGU General Assembly (2014), Vienna, Austria. NASA. “Saturn.” Solarsystem.nasa.gov (2014). Web. http://solarsystem.nasa.gov/planets/profile.cfm?Object=Saturn. Sagan, C., B. N. Khare, and J. S Lewis. “Organic matter in the Saturn system.” Saturn (1984), pp. 788-807. Seeds, Michael and Dana Backman. Foundations of Astronomy. Massachusetts: Cengage Learning, 2012. Smith, Bradford, Laurence Soderblom, Raymond Batson, Patricia Bridges, et al. “A New Look at the Saturn System: The Voyager 2 Images.” Science 215(1982): 4532, pp. 504-537. Read More