Phases+of+the+Moon+and+Lunar+Months

The **new moon** occurs when the moon is positioned //between// the earth and sun. The three objects are in approximate alignment (why "approximate" is explained below). The entire illuminated portion of the moon is on the back side of the moon, the half that we cannot see. At a **full moon**, the earth, moon, and sun are in approximate alignment, just as the new moon, but the moon is on the opposite side of the earth, so the entire sunlit part of the moon is facing us. The shadowed portion is entirely hidden from view. The **first quarter** and **third quarter** moons (both often called a "**half moon**"), happen when the moon is at a 90 degree angle with respect to the earth and sun. So we are seeing exactly half of the moon illuminated and half in shadow.


 * __Lunar Month__**

The time it takes the moon to revolve around the earth: 29 days 12 hours 44 minutes

A lunar month is a period of time measured in relationship to the movement of the moon. There are actually several different ways to calculate a lunar month, which means that it can vary in length depending on which system is used. Several religions use lunar months to establish their calenders and the lunar month is also sometimes seen used to mark time in a pregnancy; a pregnancy is around 10 lunar months long.