The Sun and the Moon in Our Sky

The Sun is a star — an enormous ball of hot, glowing gas. It makes its own light and heat, which is why it is so bright and so warm. It looks small in our sky only because it is very, very far away.

The Moon is Earth's closest neighbour in space. Unlike the Sun, the Moon makes no light of its own. We can see it because sunlight lands on it and bounces back to us — a little like a mirror in the sky.

The Moon slowly travels around the Earth, taking about a month to go all the way round. As it moves, the lit-up part we can see changes shape — a thin crescent, then a half, then a full round Moon, and back again. These changing shapes are called the Moon's phases.

Worked example. On a clear night the Moon looks bright — but if the Sun could be switched off, the Moon would go dark, because it has no light of its own. The Sun is the true light; the Moon only passes it on.