1. As the Moon orbits our planet, its varying position means that the Sun lights up different regions, creating the illusion that the Moon is changing shape over time. This is because it rotates once on its axis in exactly the same time it takes to orbit Earth – 27 days and seven hours.
2. The phases occur because the Sun lights different parts of the Moon as the Moon revolves around the Earth. That means the reason we see different phases of the Moon here on Earth is that we only see the parts of the Moon that are being lit up by the Sun.
3. During the New Moon the far side of the Moon is illuminated by the Sun, while the side that faces the Earth lies in darkness so the Moon is invisible. As the Moon follows its path from the New Moon position more and more of the Earth-facing side becomes illuminated resulting in the “waxing” phases.
