Question

What causes the Moon's phases?

Answer 1

The moon's phases are dependent on the relative position of the Earth and the Sun respectively.

Moon does not make its own light like the Sun. Instead, the moon reflects the Sun's light just like the Earth.

Whenever the the position of the moon lies between the Earth and the Sun, the moon casts a shadow (partial) on Earth. This results in the moon's phases. This is the reason that the moon appears different during every night. The phases changes from fully dark (new moon) to thin crescent and then into fully bright (full moon). The brightness or illuminated part gradually changes between the phases.