Structure and Layout of the Solar System
The Sun is a main sequence G2 star that contains 99.86% of the system's known mass. Its two largest orbiting bodies, Jupiter and Saturn, account for 91% of the remainder.
In broad terms, the charted regions of the solar system consist of the Sun and its planetary system: the eight bodies in relatively unique orbits commonly called planets or major planets and two belts of smaller objects, which can be called minor planets, planetoids, meteoroids, or planetesimals. Pluto, the ninth planet, is also considered a member of the outer belt, and its status is currently uncertain. Most objects in orbit round the Sun all lie within the same shallow plane, called the ecliptic plane, and orbit in the same direction. Many are in turn orbited by moons, and the largest are encircled by planetary rings of dust and other particles.
The major planets are, in order, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto.
Distances within the solar system are measured most often in astronomical units, or AU. One AU is the mean distance between the Earth and the Sun, or 149 598 000 kilometres. Other units in common use include the gigametre (Gm, one million kilometres) and the terametre (Tm, one billion/milliard kilometres).
Pluto is roughly 38 AU (5.9 Tm) from the Sun, while Jupiter lies at roughly 5.2 AU (778 Gm).
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