Why is the crescent moon at sunset sometimes tilted like a backwards “C”, and sometimes flat on its back like a “U”?
Short Answer: This is a tough question, and one that even the experts make mistakes on. It’s similar to the cause of the seasons, but more complicated. The short answer is that it’s caused by the fact that the Earth is tilted 23.5 degrees, and that the Earth orbits around the sun. In Madison, Wisconsin (USA), and at similar latitudes, this causes the waxing crescent moon to look like a backwards “C” in September, and a “U” in March. [See the images to the right.] This difference has been noted throughout history, and has become the subject of folklore and superstitions, such as referring to these as a “wet moon” and a “dry moon”, with misguided weather and climate connections. Don’t worry too much about which is “wet” and which is “dry”, because you can find references each way. The long answer, with diagrams, is longer than we’d like to include on this page, so click here for more.
