Sun and its planets. Artwork of the eight planets of the solar system arrayed from top to bottom in their order from the Sun (at left). The size of the Sun and planets is to scale. The four small, rocky planets of the inner solar system are Mercury, Venus, Earth and Mars. The four large, gas giant planets of the outer solar system are Jupiter, Saturn, Uranus and Neptune. In August 2006, Pluto (not shown) became a Dwarf planet. Planetary rings and moons, and a solar flare, are also shown. The Sun contains 99.9% of the mass of the solar system.