The Solar System
The solar system is made up of a star called the sun, nine major planets, their satellites (moons), comets (particles of dust and frozen gases), asteroids (planetlike objects), and meteoroids (pieces of iron, stone and frozen gases). The nine planets, in order of their distance from the sun, are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. Jupiter is the largest planet and Pluto is the smallest. The sun is over 1000 times as heavy as Jupiter.

The sun is thought to have existed for over 5 billion years. It provides all the light and heat for the other planets. Without its sunlight they would not be visible in the sky. All of the planets move around the sun in circular patterns called orbits and the sun's gravitational pull stops them from moving out of these orbits. We have night and day because the Earth is also spinning round on its axis. It is daytime on the part of the Earth that is facing the sun and night-time on the part that is not. The solar system is only a small part of our galaxy (a large group of stars). Our galaxy is called the Milky Way.