Earth-That-Was could no longer sustain our numbers; we were so many. We found a new solar system: dozens of planets and hundreds of moons. Each one terraformed- a process taking decades- to support human life. To be new Earths.
The Central Planets were the first settled and are the most advanced, embodying civilization at its peak. Life on the outer planets is much more primitive and difficult. That’s why the Central planets formed the Alliance, so everyone can enjoy the comfort and enlightenment of true civilization.
That’s why we fought the War for Unification…. There are dangers on the outer planets. So why would they fight so hard against us? … We’re not telling people what to think. We’re just trying to show them how.
Standard Introductory Lesson on the War for Unification