Moon phases. Composite timelapse image of the phases of the Moon (outer ring), as seen in the sky during a lunar month, with an artwork showing why they occur (inner ring). The Moon phases are (anticlockwise from top): new moon causing a sol ar eclipse; waxing crescent; first quarter; waning gibbous; full Moon; waxing gibbous; last quarter; & waning crescent. Lunar phases occur because the Moon does not produce light, but reflects sunlight (coming from top). As it orbits the Earth (blue), parts of the Moon (green) facing our planet are shadowed by the Moon itself. New Moons occur when the Moon lies between the Earth & Sun, & full moons occur when the Moon is furthest from the Sun.
