Groups of galaxies
Galaxies cluster in local groups. Our group has two subgroups centred on the biggest members, the Milky Way and the Andromeda

Milky Way
The Milky Way is a spiral, rather like a Catherine wheel, burning with the light of mire than 200 billion stars. Our Sun lies about two-thirds of the way out from the centre.

Sun
Our Sun, the central star of the Solar System, is a luminous ball of burning gas. Its massive gravity guides the nine planets, including the Earth, around the sky.

Earth in space
The Earth is a third closet planet to the Sun. It is unique in the Solar System in having vast oceans of liquid water and an oxygen-rich atmosphere.