Wednesday, April 4, 2012
Galileo discovered Saturn's rings in 1610, using his newly invented telescope. His telescope, however, wasn't clear enough for him to tell they were rings. He thought they were large moons, almost half the size of Saturn. However, when he observed Saturn later, the moons had disappeared. Later, an astronomer discovered that the "moons" were actually a flat disk, which had been turned edge on to Earth when Galileo observed it. Saturn's rings turn edge-on to Earth every fourteen years. After that, another astronomer discovered that the flat disk was actually rings around the planet.
The rings of Saturn start about 6,000 kilometers from the planet and extend 480,000 kilometers. They are wide, but very thin, about a kilometer thick on average. They seem to be made up mostly of small particles of ice and rock. There are seven rings altogether.
Other planets also have rings. A spacecraft, sent to Jupiter, flew right through them with no one noticing anything at the time. The rings are as wide as Saturn's, but darker. Neptune and Uranus also have thin rings.
Eventually, the rings of Saturn will dim. Micrometeorites will smash the ice crystals in the rings. Left will be fragments of black rock and metal and dirty ice. This process will wear away at the rings. The rings will gradually grow darker and thinner until there is nothing left. Enjoy them while you can.