(Event) The Great Exodus
Humanity left the Old Earth after years of conflict over diminishing resources and political struggles. After a limited Nuclear exchange, the major world powers began focusing efforts on abandoning the homeworld in search of new worlds to settle.
Originally started by the Western Alliance with Exodus ship 'Eridonia', the Exodus was intended to colonise Mars, but discovery of a Wormhome in the outer reachs of the Sol System, and CEG interest in Mars prompted a more distant target. Eventually, the Eridonia would find herself in another Galactic Arm - the Aquarius Cluster.
The Descendents of the Eridonia would go on to form the largest and most powerful civilisation in known human history: The Unified Terran Nations, with the Capitol world of Eridonia - named for the the Ark that carried them to the stars.
The United Kingdom is known to have initiated its own exodus, arriving in the Aquarius Cluster sometime before the Eridonia arrived - supposedly through the same Wormhole. The UK would go on to leave Aquarius forever after limited contact with the early UTN. Their current fate is unknown.