dipper@utastro.UUCP (Debbie Byrd) (01/15/85)
The most inconspicuous of the bright planets can be seen near the moon Wednesday morning. More -- after this. January 15 Saturn and the Moon Before the sun comes up Wednesday morning, you can see the planet Saturn. Saturn isn't as bright as the other visible planets. With the naked eye, it isn't all that easy to pick out. But you can see it before sunup Wednesday as the brightest thing in the vicinity of the moon. Saturn of course is known for its system of rings -- but the Voyager spacecraft also discovered that a region of hot gas encircles the planet. This hot gas around Saturn makes a doughnut-shaped cloud that extends from nearly 200 thousand to nearly 500 thousand miles above the planet's cloudtops. Temperatures range from 600 million to more than one billion degrees Fahrenheit! That's much hotter than the solar corona, the outer atmosphere of the sun. It's also about twice as hot as a similar doughnut-shaped region surrounding the planet Jupiter. Voyager 2 plunged through the hot gas around Saturn -- and survived because the density of gas in the cloud is very low. The relationship between density and heat is important -- a fact you'd notice at once if you stuck one hand in a hot oven and the other in a pan of boiling water. A few minutes in a hot oven wouldn't burn your hand -- but water at the same temperature would since atoms in water are much more densely packed than atoms in air. In the same way, the hot gas around Saturn IS very hot -- but not very dense. Script by Deborah Byrd. (c) Copyright 1984, 1985 McDonald Observatory, University of Texas at Austin