Moon Monday: Prometheus

Happy Monday! Here's a picture of Prometheus. You may think it's a picture of Saturn. Look hard, toward the bottom, and you'll see Prometheus, doing its part to keep the F ring in line.

Imagine standing on that world, constantly having Saturn above your head? I'm not too sure what the rings would look like from Prometheus -- maybe just a thin dark line across the sky.

Prometheus is a long and skinny moon, about 150 by 100 by 70 kilometers. At that size it's roughly 10 times bigger than Deimos, the mini-moon of Mars that I featured last week. One long end of Prometheus always points at Saturn, and the other always points away. Prometheus is one of a ton of little ring-system moons, a feature that's common to all the giant planets. Look at the diversity of Saturnian moons seen from Cassini, and ask yourself what the poorly imaged ringmoons of Jupiter, Uranus, and Neptune look like.