Structure

The galaxy was between 100,000 and 120,000 light years across, or 37,000 parsecs (a parsec is 3.258 light years), and approximately 13 billion years old. The galaxy's luminous disk contained some four hundred billion stars, of which around a quarter had been properly surveyed by the galactic community by the time of the Galactic Empire. The luminous disk revolved around the Galactic Center, a supermassive black hole that massed as much as four million suns. As late as the Declaration of a New Order, only probe droids had ever visited the black hole at Galactic Center.

The galaxy bulged around Galactic Center to form a bright sphere known as the Deep Core. This region was around seven thousand light-years across and contained some thirty billion tightly-compacted stars. Towards the center the stars of the Deep Core were only around a hundredth of a light-year apart, and were known to collide and rip out each other's stellar cores. Most of the stars of the luminous galaxy were in a disk of spiral arms rotating around the Deep Core. Galactic civilization named four spiral arms: the Bakchou Arm, the Ettarue Arm, the South Arm, and the Tingel Arm. The brightest supergiant stars were concentrated in the spiral arms, as well as glowing clouds of gas and dust, which contributed to the apparent gaps between the arms even though those areas were full of stars.

Most stars were within a thousand light-years above or below the plane of the luminous disk, forming a two thousand-light-year region known as the "thin disk". For three thousand, five hundred light-years on either side was the "thick disk", which was poorer in stars than the thin disk and even fewer of these had a system of planets.

Stellar Halo

Beyond the thick disk was the stellar halo, a huge sphere surrounding the entire galaxy with a few billion stars in highly elliptical orbits. Nearly two hundred globular clusters orbited in this region. The globular clusters were typically lifeless, packing hundreds of thousands of extremely old, inhospitable stars into only a hundred light-years. Many of the globular clusters, however, were considered extremely beautiful sights, such as Cosm's Well.

The galaxy was orbited by seven dwarf satellite galaxies, some of which contained twenty billion stars. They were ranked in order of distance. The closest was Companion Aurek, also known as the Rishi Maze, a complex tangle of stars high above the galactic plane. Companion Besh, also known as Firefist, was some 150,000 light-years away from the galaxy and had only ever been surveyed by probots. The other satellite galaxies, Companions Cresh through Grek, were much further out. Most of the Companions were described as having ancient, metal-poor remnants of stars and not much life.

A hyperspace disturbance beyond the edge of the galaxy severely complicated hyperspace travel outside the disk and generally discouraged extra-galactic exploration. A band of whorls and eddies that spun around the galaxy too quickly to be traversed at faster-than-light speeds, a number of astrophysicists believed this to be a creation of a mysterious ancient race known as the Celestials. Beyond the galaxy's rim, separating it from other galaxies, was a vast expanse of starless space known as the Intergalactic Void.