Information on the 8 Moon Phases

The moon is a sphere and one-half of it always faces the sun. It is Earth's relation to the sun and the moon that gives us the perspective of eight different light and shadow phases.

New Moon

The surface is completely shadowed. The moon is between the Earth and moon. The moon is not in eclipse because it is not in Earth's shadow. All the sunlight is striking the far side of the moon, which we cannot see.

Waxing Crescent

Decreasing shadow portion. Waxing means the illumination is expanding. Crescent means less than half is illuminated.

First Quarter

Known as a "half moon," the moon is at a 90-degree angle to both the Earth and the sun. The right half is lit. This occurs approximately one week after the new moon. It takes 29.5 days for the moon to travel around the Earth.

Waxing Gibbous

Waxing means an increase to the sunlit portion. Gibbous means that more than half is illuminated.

Full Moon

In its orbit the moon is now 180 degrees from the sun. The surface is completely sunlit and is facing us. The far side, which we cannot see, is completely dark.

Waning Gibbous

This is an increasing shadow portion. Waning means a decrease in illumination and gibbous means more than half illuminated.

References

• Shadow Phases
• Moon Orbit