The esthetically pleasing planet Saturn is in good view tonight. It's to the lower left of the gibbous Moon as they rise in mid-evening, and looks like a bright golden star.
Saturn is pretty to look at largely because of its broad, bright rings. They're as wide as the distance from Earth to the Moon, but only a few yards thick. They may have formed fairly recently, when a small moon or a comet was pulverized by an impact with another body. Or they may have been around as long as Saturn itself, and are steadily replenished with ice and rock from its moons.
Earth probably had a ring of its own in the distant past -- not long after it was born.
A body as big as Mars probably hit Earth when our planet was only a few million years old. The collision vaporized much of Earth's outer layers and spewed this hot material into space. The debris quickly cooled to form a narrow ring.
The ring didn't last long, though. Some of its particles fell back to Earth. But many more stuck together to form a larger body: the Moon. This process may have taken as little as a few thousand years, so Earth's ring didn't last long.
Look for Saturn -- the ringed planet -- close to the Moon -- a body that was born from a ring -- tonight. They're closest at first light tomorrow, with Saturn above the Moon. And a bright star looks on from close by: Regulus, the leading light of Leo, the lion.
More about the Moon and Saturn tomorrow.
Script by Damond Benningfield, Copyright 2008
For more skywatching tips, astronomy news, and much more, read StarDate magazine.