Moon and Saturn
The Moon is a desolate ball of rock. There's no air, no water, no variety. The Sun comes up, it crosses the sky, and it sets. From the side that faces our way, Earth waxes and wanes, but it doesn't change position -- it remains a constant beacon in the black sky.
But many of the moons of other planets are much more dynamic. A couple of examples orbit the planet Saturn, which appears near our Moon tomorrow morning.
One example is the small moon Enceladus. It's basically a ball of ice that's almost pure white. What makes it interesting are geysers of water that erupt from around its south pole.
A gravitational tug-of-war between Saturn and some of its other moons heats Enceladus. That appears to create pools of liquid water beneath the surface. Water sometimes erupts from these pools, and shoots far into space. The combination of water, heat, and the right chemistry means that Enceladus could have the right conditions for life.
Another possible abode for life is the even more interesting moon Titan. It has a thick, cold atmosphere topped by a "smog" of organic chemicals. Liquid hydrocarbons pool on its surface, and may flow in rivers. And an ocean of liquids may lie beneath the surface. Put them together, and Titan may resemble an early version of Earth -- a world with all the ingredients for life.
Look for Saturn to the upper left of the Moon beginning several hours before sunrise. Saturn looks like a bright golden star.
Script by Damond Benningfield, Copyright 2008
For more skywatching tips, astronomy news, and much more, read StarDate magazine.