dipper@utastro.UUCP (Debbie Byrd) (03/23/85)
How much water is there on the red planet Mars? No one knows for sure -- but we'll talk about it -- after this. March 23 Water on Mars This Saturday or Sunday evening are especially good times to take a look at the planet Mars. Mars is now low in the west after sunset. It's not very bright -- but its visible this weekend as a ruddy "star" just above the moon Saturday evening -- and a bit below the moon tomorrow evening, Sunday. From pictures taken by spacecraft on the surface of Mars, and from orbit, we know Mars to be a vast desert -- dry, rocky, red -- with a pink sky. Mars is dry today -- but there are strong indications that in the past, possibly for only a brief time, Mars had lots of liquid water on its surface. For example, there are features on Mars that look as though they were carved by gigantic rushing rivers. And Mars still has large polar caps of ice and snow -- now more or less permanently frozen in the frigid climate of this planet -- half again as far from the sun as Earth. So, while Mars today is dusty and dry -- some astronomers suspect that there's a great deal of water still on Mars, probably mostly locked up as permafrost beneath the ground. In 1990, the United States plans to launch a new spacecraft to Mars -- the Mars Geoscience Climatology Observer. The Mars Observer could help answer the question of how much water really is there -- and what role it played in the evolution of the red world currently looking down at us from the western twilight sky. Script by Deborah Byrd. (c) Copyright 1984, 1985 McDonald Observatory, University of Texas at Austin