dipper@utastro.UUCP (Debbie Byrd) (01/06/86)
The moon is near the star Antares and the planet Saturn Tuesday morning. More -- in a moment. January 6 The Moon, Antares, and Saturn The crescent moon appears near a star and a planet on the dome of the sky Tuesday morning. The reddish point of light below the waning crescent is the star Antares. The planet Saturn is the bright object above the moon. Saturn is very large compared to Earth. Its radius is about ten times that of our world. Saturn was the first planet discovered to have encircling rings. This month we're learning more about such ring systems -- as the Voyager spacecraft approaches the planet Uranus. The uranian rings are very dark and difficult to see with telescopes on Earth. But Saturn's rings appear as a bright broad expanse even in small telescopes. The rings aren't solid. They're composed of billions of tiny pebbles of ice -- each traveling in its own orbit in the plane of Saturn's equator. The ring particles nearest Saturn travel around the planet in just under eight hours -- less time than it takes the planet to rotate. The particles farthest out orbit Saturn in l2 hours. The rings extend outward to a distance about ten times the planet's radius. Astronomers have looked for saturnian rings farther out. Either the rings don't extend any farther -- or the particles that would comprise such far distant rings are even darker than charcoal -- and we can't see them. You CAN see the planet Saturn Tuesday morning. Look toward the eastern sky before daybreak. Saturn is the golden object above the crescent moon and the red star Antares. Script by Diana Hadley. (c) Copyright 1985, 1986 McDonald Observatory, University of Texas at Austin