Earth is the third planet from the sun in the Sol System. It is unique among the Sol System planets in that it is the only one which can support human life without the aid of terraforming technology. As such, Earth has supported various life forms for several millennia.
Earth has always had a thing for conquering, and when it entered the space age, this greed for new territory only increased. In the 22nd century, Earth was subtly taken over by a new mega-corporation, Centro Systems, which expanded its empire to the moon, Venus, Mars, and several asteroids and moons in the Outer Rim. Under the Centro banner, Earth quickly colonized these territories and fought a series of wars (see: the Rim Wars, the Martian Revolution) to keep its new colonies under control.