1010. Why is it that the times at which the moon sets and rises change so much from day to day?
The moon orbits the earth about every 27.3 days, so its position relative to the sun changes from day to day. Because of the moon's movement around the earth, the moon rises and sets about 1 hour later every day. When the moon is on the sun side of the earth, it rises at sunrise and sets at sunset. Fourteen days later, when the moon is on the side opposite the sun, it rises at sunset and sets at sunrise.