SATURN

Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter. It is a gas giant with an average radius of about nine times that of Earth.[20][21] It only has one-eighth the average density of Earth; however, with its larger volume, Saturn is over 95 times more massive.[22][23][24] Saturn is named after the Roman god of wealth and agriculture; its astronomical symbol (♄) represents the god's sickle.
Saturn's interior is most likely composed of a core of iron–nickel and rock (silicon and oxygen compounds). Its core is surrounded by a deep layer of metallic hydrogen, an intermediate layer of liquid hydrogen and liquid helium, and finally a gaseous outer layer. Saturn has a pale yellow hue due to ammonia crystals in its upper atmosphere. An electrical current within the metallic hydrogen layer is thought to give rise to Saturn's planetary magnetic field, which is weaker than the Earth's, but has a magnetic moment 580 times that of Earth due to Saturn's larger size. Saturn's magnetic field strength is around one-twentieth of Jupiter's.[25] The outer atmosphere is generally bland and lacking in contrast, although long-lived features can appear. Wind speeds on Saturn can reach 1,800 km/h (1,100 mph; 500 m/s), higher than on Jupiter, but not as high as those on Neptune.

Interesting Facts:

• Saturn is a flattened ball:
  Saturn spins so quickly on its axis that the planet flattens itself out into an oblate spheroid. Seriously, you see this by eye when you look at a picture of Saturn; it looks like someone squished the planet a little. Of course, it’s the rapid spinning that’s squishing it, causing the equator to bulge out.
  While the distance from the center to the poles is 54,000 km, the distance from the center to the equator is 60,300 km. In other words, locations on the equator are approximately 6,300 km more distant from the center than the poles.
  
• The first astronomers thought the rings were moons:
  When Galileo first turned his rudimentary telescope on Saturn in 1610, he could see Saturn and its rings, but he didn’t know what he was looking at. He though that the rings might actually be two large moons stuck to either side of Saturn – ears maybe?
  It wasn’t until 1655 that the Dutch astronomer Christian Huygens used a better telescope to observe Saturn. He had the resolution to realize that the moons on either side of Saturn were actually rings: “a thin, flat ring, nowhere touching, and inclined to the ecliptic.” Huygens was also the first person to discover Saturn’s largest moon, Titan.
  
• Saturn has only been visited 4 times by spacecraft:
  Only 4 spacecraft sent from Earth have ever visited Saturn, and three of these were just brief flybys. The first was Pioneer 11, in 1979, which flew within 20,000 km of Saturn. Next came Voyager 1 in 1980, and then Voyager 2 in 1981. It wasn’t until Cassini’s arrival in 2004 that a spacecraft actually went into orbit around Saturn and captured photographs of the planet and its rings and moons.
  
• Saturn has 62 moons:
  Jupiter has 67 discovered moons, but Saturn is a close second with 62. Some of these are large, like Titan, the second largest moon in the Solar System. But most are tiny – just a few km across, and they have no official names. In fact, the last few were discovered by NASA’s Cassini orbiter just a few years ago. More will probably be discovered in the coming years.
  
• The length of a day on Saturn was a mystery until recently:
  Determining the rotation speed of Saturn was actually very difficult to do, because the planet doesn’t have a solid surface. Unlike Mercury, you can’t just watch to see how long it takes for a specific crater to rotate back into view; astronomers needed to come up with a clever solution: the magnetic field.
  To determine the rotational speed of Saturn, astronomers had to measure the rotation of the planet’s magnetic field. By one measurement, Saturn takes 10 hours and 14 minutes to turn on its orbit, but when Cassini approached Saturn, it clocked the rotation at 10 hours and 45 minutes. Astronomers now agree on an average day of 10 hours, 32 minutes and 35 seconds.
  
• Saturn’s rings could be old, or they could be young:
  It’s possible that Saturn’s rings have been around since the beginning of the Solar System – around 4.54 billion years ago. Or maybe they’re relatively brand new compared to the age of Saturn. Astronomers still don’t fully understand the origin of Saturn’s rings.
  They might have formed recently, when a 300-km ice moon was torn apart by Saturn’s gravity, forming a ring around the planet.