4.1 Dissecting the Universe

Galaxies

Within the universe, there are galaxies that contain billions of stars. Around some stars there are planets, asteroids and comets.

A galaxy contains stars, gas, and dust, all held together by gravity. Even the smallest galaxies contain hundreds of thousands of stars. The Milky Way galaxy, which is where we live, contains more than 100 billion stars.

Galaxies can be classified, or sorted, by their shape. Elliptical galaxies are either round or oval shaped. Spiral galaxies look like pinwheels with curved arms that reach out from the centre. Galaxies that don't fit into these two groups are called irregular galaxies.