Solar System

The Solar System was the star system in which the Earth was located, and in which most of human history took place. The Solar System was centred around the Sun, contained 7 major planets (3 rocky planets, 2 gas giants and 2 ice giants) and numerous minor planets, planetoids, asteroids, centaurs and comets. By the Second Century AU, the Solar System also contained numerous spacecraft, space stations and habitats.

Structure and composition
The Solar System contained a single star, the Sun, which served as it's barycentre.

The Solar System contained 30 planet bodies, including two gas giant planets (Jupiter and Saturn) 2 ice giant planets (Uranus and Neptune), three rocky major planets (Earth, Venus and Mars), ten minor planets (the largest being Mercury, Eris, Pluto, Sedna) and 13 major moons (including Earth's Moon and those around Jupiter, Saturn, Uranus and Neptune, in addition to Charon).

In addition to this, the Solar System contained numerous sub-planetary bodies (i.e those not massive enough to be rounded by their own gravity). These included planetoids such as Pallas, and Vesta, asteroids such as Eros and Cruithne, Centaurs, Comets, Meteoroids, gas and dust.

History
The Solar System formed form a protoplanetary disk 30 million years after the Sun itself, but 30 million years before the complete formation of the Earth, in approximately 4.57 billion BU. It is likely that the formation of the solar system was triggered by a supernova.

The Solar System originally contained hundreds of spherical minor planets, but most of these underwent collisions that either destroyed them (reducing them to asteroids) or caused them to merge into larger objects.

Larger rocky objects in the outer reaches of the solar system amassed huge quantities of hydrogen and helium gases in their atmospheres, becoming gas giants and ice giants.

In around 3.9 billion BU, a huge quantity of asteroids moved through the solar system, causing the late heavy bombardment.

In the centuries prior to the Century War, the humans that lived on the Earth developed spacefaring capability and sent numerous unmanned probes into the solar system, including the pioneer, voyager and new horizons probes. The first manned missions were sent to the Moon at this time. Decades later, manned missions were sent to Mars.

During the Century War, there was little exploration of the Solar System. Various parties launched manned missions to the Moon in order to claim it's resources as their own (although no lunar resources were actually used during the war). The Averte Statum launched the Sun Gun into space in 30 BU. The weapon was parked at the L1 Lagrange point, a vantage point form which it could focus a large area of solar energy into a single beam, and direct that beam at the Earth. The Sun Gun was destroyed in 11 BU by a nuclear weapon dispatched by the Australian Empire and the Vostok Union.

During the Dark Ages, exploration of the Solar System resumed under the World Empire. Permanent bases for human habitation were constructed on the Moon, Mars, Venus, Mercury, Ceres and the Jovian Moons.

During the Settlement, millions of people emigrated from Earth to inhabit the various other planets of the solar system, even though terraforming was still in it's infancy. The outer solar system, including very distant bodies in the scattered disk, was colonised. The first manned vessel reached the outer Oort Cloud in 144 AU.

During the Sleeper Age and the following Superluminal age, more and more spacecraft began to leave the Solar System. In addition to this, the solar system became populated with ever more large spacecraft, space stations and habitats.