Solar system planetary distances. Illustration of the solar system, indicating the distances of the planets from the Sun. The innermost planets, Mercury to Mars, are huddled very close to the Sun, within 1.6 astronomical units (1 AU = Earth-Sun distance). The giants, meanwhile, are an order of magnitude further out, with Neptune fully 30 times the distance from the Sun that Earth is. Dwarf planet Pluto orbits in the Kuiper Belt, at a distance of 39.5 astronomical units. The giants and the rocky inner planets are separated by a vast, sparse reservoir of Solar System debris, the asteroid belt.