 This was made possible by the space tunnels, a network of FTL warp gates that were created by a now-lost progenitor race.Humanity is not united under a common government and political system; instead, the various governments in the Solar System and beyond have united as the "Solar Alliance Defense Network" in light of the war against the Fallers.The Terrans have also discovered a number of alien races, most of them vastly similar in body format, living conditions and even DNA, leading to the hypothesis that the aforementioned progenitor race seeded the galaxy with sentient life, which then evolved according to the conditions on each planet.