The Pleiades Nebula, California Nebula, Colonia Region, Witch Head Nebula, and Coalsack Nebula have become major hubs of expansion since the start of the 34th century. A few dozen isolated Asteroid Bases have been built in various nebulae. Human settlements are considerably rarer outside the bounds of the Core Systems.
The Core Systems occupy a volume of approximately 13.8 million cubic light-years that contains over 20,000 inhabited systems with more than 470,000 Starports, Outposts, Asteroid Bases, Surface Ports, and Settlements. It is where the Federation, Empire, Alliance, and other powers compete for influence, resources, territory, and control. The Core Systems, also known as the Core Worlds and The Bubble, are an ellipsoidal region of star systems approximately 200 light years in radius around Sol in the Inner Orion Spur that contains the bulk of human civilization in the Milky Way galaxy. The Core Systems highlighted in the Powerplay overview mode of the Galaxy Map
