Milky Way

The Milky Way, home to the Solar System, is one of the densest, most massive spiral galaxies known, and the dominant member of the Local Group by mass. While its stellar disc is physically smaller than Andromeda's, our home galaxy has about half again the mass of its already giant neighbor, at least 1.9 trillion Solar Masses, about a third of which is baryonic, and half of that luminous. This suggests a total stellar population around 600 billion, but could be as high as a few trillion.

An extremely pronounced bar structure appears to dominate the central region of the Milky Way, suggesting that the galaxy has yet to encounter a major collision event, though eventually Andromeda will make such a collision. The central black hole, massing an estimated 3.7 million solar masses, is exceedingly tiny compared to that of many galaxies of much smaller mass.

The Chinese call it the Silvery River, and the term Silver River has come to be another name for the galaxy. Its massive halo, close to three hundred thousand parsecs in diameter, covers many nearby dwarf galaxies, including the Large Magellanic Cloud - currently called Albacre after the name its original discoverer gave it (Al Bakr or the White Ox). Thus, mobius patterns can thrive here, making it a rather desirable region of space.

The hyporion is a unique dark matter particle found only within the halo of the Milky Way. As it is the only means by which hypomatter may be produced, it is intensely valuable, and fought over constantly - even between factions of a species.

Star systems

A few notable star systems:

Solar System - now called Lost Sol, its original location has been replaced by the Hellskearn.
Alpha Centauri - In addition to being the closest system known, it was also host to the Centaurus Relic and the first known example of extraterrestrial life, even though it was single-celled. Humans reclaimed the system after the First Hellnacht, and is sometimes considered to be their 'home' system.
Procyon - a large, yellow sun with a white dwarf companion. It is host to a number of scorched, mineral-rich worlds, hopeless for terraforming but some rogue artificial sapiences made a new civilization there, eventually becoming the Procyon Concord, and even after the Hellnachts it remains as their galactic seat.
Sirius - a very young, but brilliant star, with a white dwarf companion. The nearest hyperspace gate is here, and it is highly militarized in preparation for the Third Hellnacht.