Solar system. Computer artwork showing the planets of the solar system and their orbits. The terrestrial planets (Mercury, Venus, Earth and Mars) are separated from the gas planets (Jupiter, Saturn, Uranus, Neptune and Pluto). The asteroid belt (between Mars and Jupiter) and the Kuiper belt (between and beyond Neptune and Pluto) are also shown. The open lines represent the points of orbit where the planets pass closest to the sun (perihelia), while the closed lines represent the points of orbit where the planets pass furthest from the sun (aphelia).