The Moon's 'Blue' Last Quarter Phase Explained

As the moon moves around Earth in its monthly orbit, there are four points at which it is in exact geometry with the sun and Earth: new moon, first quarter, full moon, and last quarter. At new moon, the moon is between Earth and sun, so we are trying to see the moon's dark side in front of the brilliant sun. Because of the tilt of the moon's orbit, most of the time it passes either above or below the sun, but still close enough that it is lost in the sun's glare.