User summary:
The Starfinder Universe is a developing setting that focuses primarily on the environs of Golarion, long after the time period of Pathfinder. During the events considered in Starfinder, the planet Golarion in fact has vanished (an event referred to as "The Gap") - and investigating the mystery of the disappearance is one of the major preoccupations of the Starfinder Society.
The earliest concepts of Starfinder Universe antedate the game itself, and are found in Distant Worlds.
The Starfinder Universe has several developed regions, including Near Space, The Vast, The Drift, and, especially, the Pact Worlds System (the solar system that formerly contained the forgotten planet Gloarion).