CHRIS MADELEY / SCIENCE PHOTO LIBRARY CHRIS MADELEY / SCIENCE PHOTO LIBRARY
Gibbous Moon in the night sky. The moon passes through a complete set of phases, from new moon to new moon, once every 29.53 days (a synodic month). It is described as gibbous when more than half its disk is illuminated. The moon does not produce its own light, but it can be seen because it reflects the light of the sun. The dark areas, or 'seas', are the remains of ancient plains of lava. Craters visible are the result of meteorite impacts. The same side of the moon always faces the earth.
Model release not required. Property release not required.