The Population Wars were a series of armed conflicts that engulfed Earth and many of her original colonies when the government decide to forcebly ship off large numbers of people from the overcrowded homeworld to other planets.
The wars led to a complete breakdown of interstellar transport, known to future generations as the Hiatus.2:2 They culminated in continent-destroying bombardments of several planets, including Earth, around 3148 CE.3:7
Cinnabar was only a generation old at the time, and thus was not involved as a participant. That preserved it and similar minor colonies from asteroid bombardment, and eventually led some of them to become the new powers.2:2