SATURN
Saturn is the sixth planet from the Sun and the furthest known to classical observers (the Greeks and the Romans). It's about 95 times more massive than the Earth, and about ten times as far away from the Sun. It has a low density, so low that it could float in a bath of water if one could be found that was big enough. The most famous feature of Saturn, though, is its incredibly beautiful ring system.
Facts about Saturn
Mass (kg): 568.8x1024
Equatorial Radius (km): 60268.0
Mean Density (kg/m3): 690
Length of Day (hours): 23.9345
Period of Revolution about Sun (days): 10.23
Acceleration due to Gravity (m/s2): 9.05
Mean Orbital Velocity (km/s): 9.64
Inclination of Axis (degrees): 26.73
Mean Distance from the Sun (AU): 9.5388
Other stuff
Storm Clouds?
The clouds of Saturn are similar to those of Jupiter, comprising of fast moving jet-streams causing, as on the biggest of the planets, eddies and even a red spot, albeit one that is much smaller than that on Jupiter, being only 6000km across compared to Jupiter's 26,000km whopper. Saturn also possesses many other ovals, mainly in the north, but unlike on Jupiter, they tend to move around each other when they meet - on Jupiter they tend to coalesce. Little is known about how Saturn's cloud layer behaves. It is now known, however, that close to the equator the cloud bands reach high speeds of 480m/s, but at the poles the speeds are zero. This indicates that the clouds merely 'keep pace' with the rotation of the planet around its axis. Above the cloud layer lies the atmosphere of the giant. Extending outwards to a height of 30km, this atmosphere is made up of ammonia clouds. The Voyager craft have shown that the upper atmosphere contains some colored clouds too, but these are at an unknown height.
The Rings
The rings of Saturn are the most spectacular of any planet in the known solar system. They were first spotted by Galileo in July 1610, but his telescope wasn't quite up to scratch, and even though he saw the rings in the most prominent way (with the full face of the rings towards him), he thought Saturn was a triple planet. When he looked again seven years later, the rings were edge on and, being only 1km thick, had seemingly vanished. He declared: 'Saturn has swallowed her children.' We now know that Saturn's rings are visible in different aspects depending on the relative position of it and Earth. The cycle follows a 14.5 year period from fully open, through edge-on, and back to open. This mystery was finally cleared up by the Dutch astronomer Huygens, who managed to observe the ring system in 1655. However, it wasn't until 1856 that Clerk Maxwell managed to explain what the rings actually were. His calculations showed hat a solid ring would be torn to tatters by gravitational effects, so he predicted that the rings were made up of many small, electrostatic particles. This has since been borne out by further observations and two satellite flybys. Until the Voyager spacecraft passed Saturn within the past three decades, no one realized just how many rings there are, and just how thin they are. Previously, upper estimates put the number at three. There are, however, at least 10,000 rings arranged into bands, with 'shepherd moons' keeping them on the straight and narrow. It is also known that electrostatic influences help keep them in line, with the outer three ringlets being braided. Lightning has been detected from the rings.
The Satellites
Saturn has 34 satellites, most of which are pretty wack. It is perhaps in the nature of this odd planet to have odd moons. For example Titan, the largest moon of Saturn, is covered by a dense orange fog that is difficult to penetrate. It consists of 90% nitrogen, but has complex organic molecules present, including some amino acids. While doubting the existence of life at such low temperatures (liquid nitrogen is thought to form lakes, rivers and seas on its surface), scientists are using Titan as a model for what the earliest stages of life look like. Furthermore, the moon Tethys shows evidence of geothermal activity and has a rift valley along its surface and Mimas has an impact crater covering a quarter of its surface, making it look like a giant eyeball. The impact is thought to have had a force just short of that required to shatter the poor little ball of ice and rock into smithereens. Both moons are weird, however neither as weird as Janus or Epimethius, moons who's orbits are so close to each other that they should have collided long ago. What has prevented that is that when they approach each other, a peculiar effect of gravity makes them flip positions so the faster becomes the slower, and vice versa. Very weird indeed...
See? It's Pretty, Ringy, and Odd.
See also: The other planets listed: Jupiter and Earth
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