What is the setting of Citizen of the Galaxy by Robert A. Heinlein?

Citizen of the Galaxy is set in our galaxy at some point in the future. We are not told exactly how far in the future the events take place, but we can assume that it is several centuries after the present day. Humanity is no longer bound to earth, but has spread throughout the galaxy, occupying many planets and moons. Earth is still proudly regarded as the birthplace of the human race, but many people are so far removed from earth, by both distance and time, that they regard the stories they hear of earth to be mere legends. Earth is also at the center of the Terran Hegemony, which at first appears to be one large government entity, but later turns out to be a loosely connected alliance of independently governed planets.