Fun facts about the Moon

The Moon is Earth's only natural satellite. At about one-quarter the diameter of Earth (comparable to the width of Australia), it is the largest natural satellite in the Solar System relative to the size of its planet, the fifth largest satellite in the Solar System overall, and is larger than any dwarf planet Why does the Moon change shape? Phases of the Moon © NASA/Bill Dunford The Moon goes through a series of phases each month, from the new Moon to the full Moon and back again. So why is it sometimes a full circle and sometimes only a crescent – or even not visible at all? The Sun’s light will only hit one half of the Moon at a time, giving it a day side and a night side – just like on Earth. The shape that the Moon appears to us on Earth depends on where it is compared to the Sun. If it’s directly between the Earth and the Sun, then the Sun’s light only falls on the side we can’t see, and so we get a new Moon: it appears completely dark in the sky. However, when the Moo...