Here's how it works:
* The Moon's orbit: The Moon orbits the Earth, and as it does, the angle at which the Sun's light hits the Moon changes.
* Lunar phases: The different amounts of illuminated surface we see from Earth create the lunar phases, which are:
* New Moon: The Moon is between the Earth and the Sun, so we see its dark side.
* Waxing Crescent: A small sliver of the Moon's illuminated side becomes visible.
* First Quarter: Half of the Moon's illuminated side is visible.
* Waxing Gibbous: More than half of the Moon's illuminated side is visible.
* Full Moon: The entire illuminated side of the Moon is facing the Earth.
* Waning Gibbous: Less than half of the Moon's illuminated side is visible.
* Last Quarter: Half of the Moon's illuminated side is visible (but the opposite half from the First Quarter).
* Waning Crescent: A small sliver of the Moon's illuminated side is visible.
So, as the Moon goes through its phases, the amount of light reflecting from its surface appears to increase until it reaches the Full Moon, and then it appears to decrease again.
