Wednesday, January 25, 2006
Crescent
Saturn as seen from Cassini yesterday. Distance about 1.8 million miles. If you want to get a sense of what the planet would look like with the unaided eye (but hopefully protected behind a porthole of some kind) lean back from your computer and put three fingers together at arms' length. Once Saturn's disk is as wide as your fingers (excluding rings) that will be about how the planet would look to an observer there.
By comparison, Saturn would look about forty times as wide as the moon if it were the same distance away. 1.8 million miles is a bit more than seven times farther than that; giving us a nice yellow crescent about five-and-a-half times as wide as the moon is seen from earth.
Keep in mind also that if you lived on a base on a moon closer than Titan, you would always see the rings like this: thin and edge on. All of Saturn's moons from Titan on in orbit in the same plane as the rings. What you would see is the shadow of the rings interrupt that lopsided crescent on a cycle of 29.5 earth years. Would you deduce it was the ring shadow, or would you think it to be something else going on on the planet?
