What Causes Phases of the Moon?
The phases of the moon as seen from the earth depend on the position of the moon and the earth in relationship to the sun. What we see as phases are the sun’s reflection on the moon. Hence if all three are perfectly aligned, we see a full moon as there is no shadow from the earth. As the bodies move, the earth blocks some of the sun’s rays and creates a shadow or dark spot as we view the moon, making it appear smaller and smaller, then gradually larger again as the days go on, until they are all once again lined up perfectly and we have another full moon.
