This is of course a broad generalization with sectors assigned to whichever faction has the greatest control. This is also just before major hostilities break out between the UEG and the Saurians, approximately 280 years after the war between Earth and the Martian/L-3 Alliance. Closer to the galaxy's core, there is a "Dead Zone" where probes fail and starships that enter never return. Telescopes and other sensors also are of limited use for precise navigation due to the ambient radiation levels but there also appears to be some other kind of interference at work. As such, there are modern and ancient buoys warning vessels to stay away, leading to increased speculation and unusual rumors as to what may lay beyond this border. This would also be the basis for the standard map in a 4X type game.