The Sun and the Solar System

The Sun and the Solar System

Our nearest star is not one of the tiny points of light twinkling in the night sky. It is an enormous ball of fire that lights and warms our whole world - the Sun.

The Solar System consists of the Sun and all the objects going around it. These objects include eight main planets, moons, glowing comets and lumps of rock called asteroids and meteoroids. In the outer reaches of the Solar System, there are also small planets called dwarf planets. All these objects go around, or orbit, the Sun. They travel around the Sun not in circles, but in elongated ovals called ellipses. The strength of the Sun's gravity keeps the objects in the Solar System from flying away into deep space.

Where is the Sun?

The Sun is about two-thirds of the way from the centre to the edge of the Milky Way. Despite being a small-to-medium star, the Sun is still around 109 times wider than Earth. In space terms, the Sun is near to Earth (150 million kilometres, or 93 million miles), which is why it looks huge in our sky. Earth is the third planet from the Sun.

How the Sun shines?

Like all stars, the Sun is mainly hydrogen. The immense pressure and temperature at the Sun's centre cause its hydrogen atoms to undergo nuclear fusion. This means they squash together to form heavier atoms of helium and give out vast amounts of heat, light and other forms of energy.