Here's why:

* Lunar Cycle: The moon orbits the Earth roughly every 29.5 days, which is called a lunar cycle.

* New Moon: A new moon occurs when the moon is positioned between the Earth and the Sun. Since the sunlit side of the moon is facing away from us, we can't see it.

* Phases: As the moon orbits, it appears to change shape (phases). After the new moon, we see a waxing crescent, first quarter, waxing gibbous, full moon, waning gibbous, last quarter, and waning crescent before the cycle starts again with the next new moon.

Let me know if you have any other questions about the moon!