DEFINITION

The Solar System is made up of the Sun, the planets, their moons, asteroids and comets

The Sun

The Sun is a star that lives at the centre of the Solar System. Its huge gravity holds the planets in place.

The planets

The planets all revolve around the Sun. There are nine in total - Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto.

Moons

Moons rotate around their parent planet. Earth has one moon, but some planets have over 30. Only Mercury and Venus do not have any moons.

Asteroids

Asteroids are rocky bits of debris up to 1,000km (620 miles) across. Most live in the asteroid belt between Mars and Jupiter. They are the remnants from early planets that collided and were torn apart.

Comets

Comets are dirty snowballs of ice and dust that revolve around the Sun in long orbits. When they approach the Sun they heat up, leaving a trail of gas behind them, which looks like a tail.