Solar system planets. Computer artwork of the nine planets of the solar system arrayed from bottom to top in order of their distance from the Sun (not shown). The four small, rocky planets of the inner solar system are: Mercury, Venus, Earth and Mars. Then come the four large, gas giant planets of the outer solar system: Jupiter, Saturn, Uranus and Neptune. Finally, Pluto is a small planet of rock and ice that orbits at the outer edges of the solar system. Not to scale.