Our Solar system began to form about billion years ago from a cloud of dust and gas. This dust and gas began to spin and flatten out into a disc shape. In the centre of the disc was formed the Sun and other planets. At first people have been watching the night sky through telescopes, now we send spacecrafts to take photos of the Solar system.There are nine planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. They all orbit the Sun.