dipper@utastro.UUCP (Debbie Byrd) (09/30/84)
You'd have a very good view of the planet Mars -- if you stood on its innermost moon. More about the Martian moon Phobos -- after this. September 23 The View from Phobos Earth's moon is nearly one-fourth the size of the Earth. Both worlds in our double planetary system are round -- and separated by approximately two hundred and forty thousand miles. From the moon, the Earth appears as a blue-white globe -- four times the diameter of the full moon in our skies -- and sixty times as bright. The two Martian moons are tiny in size compared with their planet Mars. Phobos and Deimos are very irregular in shape. They look like gigantic cratered boulders -- or small asteroids -- or even oversized Idaho potatoes! The larger moon -- Phobos -- is less than seventeen miles in diameter at its widest point. Phobos is also the inner moon to Mars -- its near-circular orbit brings it within thirty-seven hundred miles of the Martian surface. Phobos moves very rapidly around Mars -- revolving around the planet much faster than Mars rotates. Three times a day -- with respect to the stars -- the small rocky moon orbits the planet -- sweeping a tiny elongated shadow over the Martian landscape as Phobos moves between the planet and the sun. One of these days Phobos is likely to be a way-station -- perhaps even a kind of Ellis Island -- for people going to Mars. When our descendants stand on the side of Phobos facing Mars, the planet's huge globe will dominate the celestial view. The diameter of our moon covers only half a degree on the dome of our sky -- whereas Mars stretchs a magnificent heart-stopping panoramic 42 degrees across the sky of Phobos. Script by Diana Hadley. (c) Copyright 1983, 1984 McDonald Observatory, University of Texas at Austin