We're looking at the Earth's North pole. The planet is rotating around its axis, and the Moon is orbiting around the Earth. We can see the line of sight that an observer enjoys from the Earth to the Moon. When you reduce the scale you are making the distance to the moon a bit more realistic. If the Earth is too close to the Moon, the lunar phase changes drastically in one single night. Change the scale of the Earth to appreciate less drastic changes per night in the lunar phase. You can also speed up the lunar cycle.
Notice that the moon always presents the same face to the Earth. Such face is gradually shadowed and illuminated as the moon orbits around the Earth. This simulation looks at the moon from "above", not from an Earthling observer's horizon. The music is from Carl Sagan's "Cosmos" TV series.
