Biography of a Planet

In Ms. Gardner's class we've been talking about the Nebular Hypothesis and accretion. There is evidence of this on the planet Saturn, but there is also problems involving the idea. The evidence of the Nebular Hypothesis on Saturn is the rings around the planet. It is thought that the rings were a satellite that crashed into Saturn, proving that rocks did crash into other planets. Also, it is a Jovian planet (a gas giant) so it's size and diameter work perfectly for this hypothesis. It's said in the theory that the gas giants formed something like the terrestrial planets, but with gases, and since there were so much gas, the planets (Jupiter and Saturn) became huge in size. Once the gas becomes all used up, the planets could grow no longer. Some problems involving this idea on Saturn are the fact that the rings orbit around Saturn in half the time it takes Saturn to rotate. This is a problem because of the planet Mars' satellites. One of them (Phobos) was found to orbit Mars 3 times around as Mars rotates once. It was thought that Saturn would have an explanation for this, but the rings orbited slower. Then a satellite was found orbiting Saturn and it was orbiting the opposite way of the planet's rotation!

http://www.plantanimalmineral.com/universe/the-nebular-hypothesis
http://en.wikipedia.org/wiki/Nebular_hypothesis