JOHN SANFORD / SCIENCE PHOTO LIBRARY JOHN SANFORD / SCIENCE PHOTO LIBRARY
Waxing half Moon. Optical image of a waxing (increasing in apparent size) half Moon. This stage in the phases of the Moon is known as the first quarter. The phases of the Moon (new Moon, first quarter, full Moon and then back to new Moon) are due to its orbit around the Earth. When it lies in between the Earth and the Sun, only the unlit side faces us (new Moon). When the Earth lies between it and the Sun, we see a full Moon. Each cycle takes around 28 days. The lunar hemisphere that faces Earth has bright highlands and dark seas, or maria, which are lowland plains full of dark solidified lava. Several large craters are also seen. Photographed from California, USA, on 26 January 2007.
Model release not required. Property release not required.