The sectors that make up the Distant Fringe are generally considered to lie on the rimward edge of the Orion Spur, the local spiral arm of the galaxy. The far (rimward) edge of the Great Void – the coreward edge of the Perseus Arm, the next spiral arm outwards – lies around 600 parsecs distant at its closest point. It has never been charted in detail.
The Great Void is the vast and largely empty region of space, generally running spinward-trailing, that lies between the spiral arms. It is considered to have an average width of some 800 parsecs and an approximate length of around 10,000 parsecs, and covers an estimated 5000 sectors. While they do contain occasional isolated stars, for the most part these so-called Void Sectors are empty.
The Great Void is composed of the interstellar medium (ISM), the matter and radiation that exists within the space between the stars. This matter includes gas in ionic, atomic, and molecular form, as well as dust and cosmic rays.
The following sectors are considered to lie within the Great Void:
- Abyss Sector; Chasm Sector; Deep Sector; Denison Sector; Gulf Sector; Lon Beon Sector; Pestilent Sector; Quell Sector; Samardin Sector; Stand Sector; and Yearn Sector.
The Great Void is sometimes referred to as "Old Man Void", particularly in poetry and song.