From UFStarfleet LCARS
The Sol system (or Solar system or Terran system) is a star system located in Sector 001, in the Alpha Quadrant. It contains 9 planets. The Sol system formed approximately 5 billion years ago out of a slowly condensing cloud of debris and gas left over from previous supernovae.
Location
The Sol system is located in the Sol Sector on the spinward edge of the Alpa/Beta Quadrant Border. Earth, capital planet of the United Federation of Planets is located within the system along with many key Federation orbital facilities.
The Solar System consists of the Sun and the astronomical objects bound to it by gravity, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. Of the many objects that orbit the Sun, most of the mass is contained within eight relatively solitary planets whose orbits are almost circular and lie within a nearly flat disc called the ecliptic plane. The four smaller inner planets, Mercury, Venus, Earth and Mars, also called the terrestrial planets, are primarily composed of rock and metal. The four outer planets, the gas giants, are substantially more massive than the terrestrials. The two largest, Jupiter and Saturn, are composed mainly of hydrogen and helium; the two outermost planets, Uranus and Neptune, are composed largely of ices, such as water, ammonia and methane, and are often referred to separately as "ice giants".
The Solar System is also home to two regions populated by smaller objects. The asteroid belt, which lies between Mars and Jupiter, is similar to the terrestrial planets as it is composed mainly of rock and metal. Beyond Neptune's orbit lie trans-Neptunian objects in a region known as the Kuiper Belt. These are composed mostly of ices such as water, ammonia and methane.