Solar system. Composite computer artwork of the nine planets of the solar system that orbit the Sun (far right). In order of their distance from the Sun and anticlockwise from top right they are: Mercury, Venus, Earth, Mars (the four small rocky planets of the inner solar system), Jupiter, Saturn, Uranus, Neptune (the four large gas giant planets of the outer solar system) and Pluto, a small planet of rock and ice. Not to scale.