Planet Terra is home to the Terran Nationalists and the Eastern Alliance. The Eastern Alliance would have eliminated the Nationalists in a nuclear attack if not for the intervention of Apollo and the Galactica. Despite hopes that Galactica had finally reached its destination, it is revealed that Terra is not Earth (Experiment in Terra).
Colonists from Terra founded the Lunar Colonies. The Galactica first encounters "Earthlings" when they discover a ship from the Lunar Colonies. The people aboard were attempting to flee the influence of the Eastern Alliance by travelling to Paradeen (Greetings from Earth).