Purple Void

The Purple Void is a nebula inside the Milky Way that is notable for a high amount of artifacts, exotic stars, and habitable planets. The space immediately surrounding it is known by its human population as "Sector Prime". Many civilizations including humans inhabit this sector.

Astrography
The greatest obstacle to interstellar travel in the Purple Void is itself. Most forms of superluminal travel are impossible while passing through it, entailing specialized equipment and tricks to avoid travel at a measly c. Black holes are also threatening to spacecraft, many of them undiscovered to boot. The sector is also on the verge of experiencing a supernova.

Notable among the cosmic aberrations are green stars, which have been noted as theoretically impossible by Terran scientists. They're seen as signs that the universe has been destroyed and imperfectly reconstructed.