5 The Solar System

The Solar System

In space. The Earth is a planet. It's a huge, round lump of rock floating in space. The Earth is one of eight planets that travel around the Sun. The Sun and the planets are called the Solar System. This is what the Earth looks like from space.

What's out there? The planets in the Solar System move around the Sun. Pieces of rock, called asteroids, travel around the Sun, too.

The planets are shown close together on these pages. Really, they are very, very far apart. As well as planets, there are lots of other things that move around the Sun, from specks of dust to 'dwarf planets' such as Pluto.

How it started. Scientists think that the Solar System formed millions and millions of years ago. It began as a huge cloud of gas and dust in space, like this one. The swirling cloud of gas and dust slowly got thicker and thicker. Part of the cloud heated up, making a hot ball of gas. This became the Sun.

Over millions of years, the gas and dust spun around the Sun. Gradually, the dust and gas joined together to make the planets.