The moon doesn't actually produce any light of its own. It shines because it reflects sunlight. The reason why it appears dark at one stage of the lunar cycle is due to the relative positions of the sun, Earth, and the moon:

* New Moon: During this phase, the moon is positioned between the sun and Earth. Its sunlit side is facing away from us, making it appear completely dark.

* Waxing Crescent: As the moon orbits Earth, it starts moving away from the sun's position. A sliver of the sunlit side starts becoming visible, appearing like a crescent.

* First Quarter: At this stage, the moon is positioned at a 90-degree angle to the sun and Earth. Half of its surface is illuminated, creating a half-moon shape.

* Waxing Gibbous: As the moon continues its orbit, more of the sunlit side becomes visible, resulting in a larger, gibbous shape.

* Full Moon: The moon is opposite the sun, directly across from Earth. The entire sunlit side of the moon faces us, giving us a full, bright moon.

* Waning Gibbous: After the full moon, the illuminated portion of the moon starts decreasing, moving back into a gibbous shape.

* Last Quarter: Again, the moon is at a 90-degree angle to the sun and Earth, but this time the opposite half is illuminated, creating another half-moon shape.

* Waning Crescent: The illuminated portion of the moon continues to shrink, becoming a thin crescent before disappearing completely at the next new moon.

Therefore, the moon appears dark during the new moon phase because the sunlit side is facing away from Earth.