ASTR 122 Lecture Notes - Lunar Phase, New Moon
3 Mar 2014
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People see only the half of the moon that faces the sun and is illuminated. Lunar phases -- the different appearances of the moon. New moon -- the phase of the moon when the dark hemisphere faces earth. Waxing crescent moon-- phase in between new moon and first quarter. First quarter moon -- we see half of the moon"s illuminated hemisphere & half is dark. Waxing gibbous moon -- phase in between first quarter and full moon. The moon takes about 4 weeks to complete an orbit around the earth. The moon rotates, so we only see one face of the moon. Synchronous rotation -- it takes the moon exactly as long to rotate on its axis as it does to make one orbit around earth. The side of the moon that constantly faces away from the earth is properly called the far side.
