Moon Phases
The revolution of the Moon around the Earth makes the Moon appear as if it is changing shape in the sky. This is caused by the different angles from which we see the bright part of the Moon's surface. These are called "phases" of the Moon. The phase you see when you look at the moon depends on its location in relationship to the Sun and Earth. The Moon doesn't create any light itself; it just reflects the light of the Sun. The fraction of the moon that appears illuminated changes since the moon is orbiting the earth. The time it takes the Moon to complete one orbit around the earth (with respect to the sun) is also the amount of time it takes to complete one cycle of moon phases. This period, known as the synodic month, is about 29.5 days. The phases always follow one another in the same order.
Define Moon Phases
New moon – moon is between the Earth and Sun so it is not visible in the night sky
Waxing Crescent
Waxing - "growing" or expanding in illumination
Crescent - the moon is less than half illuminated
First quarter moon; half of the moon is visible
Waxing Gibbous
Waxing - "growing" or expanding in illumination
Gibbous- the moon is more than half illuminated
Full moon – about 2 weeks after a new moon
Waning Gibbous
Waning - "shrinking" or decreasing in illumination
Gibbous - the moon is more than half illuminated
Third quarter moon; half of the moon is visible
Waning Crescent
Waning - "shrinking" or decreasing in illumination
Crescent - the moon is less than half illuminated
New moon – Cycle begins again
Blue moon - the second full moon in a calendar month