What is the moon phase called when it is positioned between Earth and the Sun, making it invisible from Earth?

The phase of the moon when it is positioned between Earth and the Sun, resulting in it being invisible from Earth, is known as the New Moon. During this phase, the side of the moon that is illuminated by the Sun is facing away from Earth, making it difficult for observers on the planet to see the moon at all. The alignment of the moon directly between the Earth and the Sun during this time is crucial, as it prevents sunlight from reflecting off the moon's surface toward Earth, hence its invisibility.

In contrast, other phases like the Crescent or Full Moon are characterized by varying degrees of visibility. A Crescent Moon occurs when only a small portion of the moon is illuminated and visible from Earth, while a Full Moon occurs when the entire face of the moon is fully illuminated by the Sun. The Waning phase refers to the process after a Full Moon when the visible illuminated portion of the moon decreases, also making it distinct from the New Moon phase.