A new moon is the phase when the Moon is between Earth and the Sun, making the side facing us almost completely dark. During a new moon, you usually can't see the Moon in the night sky because almost no sunlight reflects off its Earth-facing surface.

The Moon doesn't make its own light. It only shines by reflecting the Sun's light, like a mirror in space. As the Moon orbits Earth each month, we see different amounts of its sunlit side. When the Moon moves to the same side of Earth as the Sun, its bright side faces away from us, leaving the side we can see in shadow. That's a new moon.

After a new moon, a thin crescent appears in the evening sky and grows night by night until we see the full moon about two weeks later. Then it shrinks back through another two weeks until the next new moon arrives. This cycle takes about 29.5 days and repeats over and over.