The Planet Saturn

     Saturn is the queen of the planets. Saturn is stunningly beautiful, with its smooth, pale-butterscotch surface and its shimmering halo rings. But it is a secretive planet. Telescopes have never pierced its upper atmosphere, and data from the "fly-byes" of the Voyager probes focused on its rings and moons. 

     We have already learned some of the facts about Saturn when we are still in elementary and high school. Here are some of  the important facts about Saturn.

     Saturn is the second most massive planet and also the second largest in size after Jupiter. It is a Gas Giant planet with a rotational period of 10-11 hours and an orbital period of 29.5 years. The rapid rotation flattens Saturn at the poles by about 10%, making it the most oblate planet. Its composition is similar to Jupiter which is also composed mostly of hydrogen and helium. Like Jupiter, it is mostly liquid and it has an internal heat source.

     The interior is probably similar to Jupiter, with metallic hydrogen responsible for the strong magnetic field of Saturn. The concentration of helium compared to hydrogen is somewhat less than for Jupiter. This is thought to be due to the colder temperature of Saturn.

    

     Although the Hubble Space Telescope can now take very good images of Saturn, our best information comes from space probes: Pioneer 11, Mariner 11 and 12, and Voyager I and II.

     The most notable feature of Saturn is its ring system. Through the telescope, the rings appear as one gleaming white hoop, but a close look reveals that they are, in fact, in 3 sec- an outer ring, a bright middle ring, and the innermost ring which is faint and almost transparent. The rings of Saturn are composed of hundreds of thousands of "ringlets", and that regions like the largest "gap" called the Cassini division, also contain fainter rings. The rings are composed of particles that are mostly ice crystals, with sizes as large as centimeters or meters. The total mass in the rings is about the size of a medium mass moon, and the rings are only about 10 km thick.

For additional facts, there are still some facts that we don't know yet. According to Fraser Cain, there are many interesting facts about planet Saturn and these are:  

Did you know that Saturn is the least dense planet in the Solar System?

     Saturn has a density of 0.687 grams/cubic centimeter. Just for comparison, water is 1 g/cm³ and the Earth is 5.52. Since Saturn is less dense than water, it would actually float like an apple if you could find a pool large enough.

Do you know that Saturn is a flattened ball?

     Saturn spins so quickly on its axis that the planet flattens itself 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. 

Did you know that 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. It wasn’t until Cristian Huygens used a better telescope to realize that Saturn actually had its famous rings.

Did you know that 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. 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.

Did you know that Saturn has 60 moons?

     Jupiter has 63 discovered moons, but Saturn is a close second with 60. Some of these are large, like Titan, the second largest moon in the Solar System.

Did you know that how long is a day on Saturn is a mystery?

     To determine the rotational speed of Saturn, astronomers have 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.

Did you know that 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 – almost 4.6 billion years ago. They have been created when a 300 km ice moon was torn apart by Saturn’s gravity, and formed a ring around the planet. It’s also possible that they’re the left over material when Saturn formed in the solar nebula. But astronomers have also found that the ring material looks just too clean to have formed so long ago, and could be as young as 100 million years old. It’s all just a big mystery.

Did you know that Sometimes its rings disappear?

    Well, they don’t actually disappear, but they look like they’re going away. Saturn’s axis is tilted, just like Earth. From our point of view, we see Saturn’s changing position as it takes its 30 year journey around the Sun. Sometimes, the rings are fully open, and we see them in all their glory, but other times we see the rings edge on – it looks like they’ve disappeared. This will happen in 2008-2009, and then again in 2024-2025.

Did you know that you can see Saturn with your own eyes?

     Saturn appears as one of the 5 planets visible with the unaided eye. If Saturn is in the sky at night, you can head outside and see it. To see the rings and the ball of the planet itself, you’ll want to peer through a telescope. But you can amaze your friends and family by pointing out that bright star in the sky, and let them know they’re looking at Saturn.

Did you know that there could be life near Saturn?

     Not life on Satur; the planet is way too hostile to support life. But there could be life on one of Saturn’s moons: Enceladus. NASA’s Cassini spacecraft recently discovered ice geysers blasting out of Enceladus’ southern pole. This means that some process is keep the moon warm enough that water can remain a liquid. And wherever we find liquid water on Earth, we find life.