During the Mid-22nd Century, Earth was gripped by a global Religious War between the Mithraic and the Atheist factions. The war saw the deployment of advanced weaponry, including the necromancer android super-weapons used by the Mithraic.
The Atheists ultimately lost the war, but managed to deploy bombs that rendered the planet uninhabitable. Either before or shortly after this, the Mithraic deployed an ark ship to colonize the planet Kepler-22b.