dipper@utastro.UUCP (Debbie Byrd) (05/21/85)
It's early morning right now on the lighted crescent of the moon. More on the lunar day -- after this. May 21 Morning on the Moon The slender silvery crescent moon is in the west after sunset this week. After sunset -- as the spinning Earth carries our part of the globe out of view of the sun -- we see the moon for only a short time before we spin out of sight of the moon as well. We see the moon this week just as night falls. But it's early morning now along the lunar terminator -- the line that divides the slender lighted crescent of the moon from the larger, darker part -- the unlit part of the moon visible in the next few days in the west after sunset. Like Earth, half of the moon is always sunlit -- but different hemispheres of the moon continually come into the light of the sun as the moon spins on its axis. The moon takes more than 27 Earth days to spin around once -- about the same time it takes the moon to complete one orbit around Earth. So the same side of the moon always faces Earth -- and we watch from a distance as that near side of the moon undergoes the long lunar day. On the moon, a lunar morning lasts an Earthly week -- because the moon spins so much more slowly than Earth. Look for the moon over the next several nights -- each evening it'll be a fatter crescent higher in the west after sunset. Remember, as you see the moon wax larger, that you're watching the long slow line of sunrise marching across the surface of another world. Script by Diana Hadley and Deborah Byrd. (c) Copyright 1984, 1985 McDonald Observatory, University of Texas at Austin