Moon Phases

Moon phases are the changing appearances of the Moon caused by its orbit around Earth. As the Moon orbits, sunlight illuminates different portions of its surface, creating the cycle of phases: new moon, crescent, quarter, gibbous, and full moon. These phases repeat roughly every 29.5 days. The phase we see depends on the relative positions of the Sun, Moon, and Earth. When the Sun illuminates the side of the Moon facing Earth fully, it's a full moon; when less is visible, it's a crescent or quarter. This cycle results from the changing angles of illumination during the orbit.