Animated graph showing the phases of the Moon over time. The phase of the Moon is on the y-axis, and time in days is along the x-axis. Starting from a half Moon with the left side lit, called a last quarter Moon, the phase moves down to a new Moon, then returns through a first quarter half moon to a full Moon and then back to the last quarter after 29.53 days. This period of the Moon's phases is called the synodic month, and is the time taken for the Moon to return to the same position relative to the Earth and Sun. See clip K006 7164 for a graph showing the Moon's orbit with respect to Earth, and K006 7161 for the two graphs combined.