Known Universe





The term the Known Universe referred to the area of the portion of the Universe that was explored and documented by humans. The vast majority of this space was claimed to be within the Imperium, the realm of the Padishah Emperors (who referred to themselves as "Padishah Emperors of the Known Universe" as a result).

Though the Padishah Emperors laid claim to ruling the Known Universe, in reality, it was considered to be at least slightly greater than the size of the Imperium itself. During the reign of the God-Emperor Leto Atreides II, the Bene Tleilax sought to establish colonies outside of the God-Emperor's Empire, but still within the Known Universe, for instance. The Tleilaxu believed that Leto's prescience ended at the borders of the Imperium (they were incorrect, however, as Leto came to demonstrate).

The size of the Known Universe increased sporadically over history, as humanity explored more and more of previously uncharted space. The most significant growth came at two specific historical points: The second instance was facilitated by the invention of Ixian No-ships, which did not require a melange-addicted Guild Navigator to pilot.
 * when space folding was invented, following the Butlerian Jihad, and
 * when The Scattering occurred, following the death of the God-Emperor.

Behind the Scenes
The borders of the Known Universe are never accurately described. Even after the merger of the Bene Gesserit and the Honored Matres, when the Known Universe was larger than it had ever been, the full extent of manned space is undisclosed.

However, some projections can be made, based upon the known locations of stars, and basic Dune history. The human race began on Old Earth, and colonized numerous worlds around other stars. These ranged from nearby stars within 20 light years, to several stars 100-200 light-years away from Earth, and the furthest known colonized star of the Imperium, Beta Lyncis, which was 410 light-years away. However, even Beta Lyncis (and its planet Ishia) is well within the Orion Arm of the Milky Way Galaxy. Also, it seems that the Old Imperium remained centered on the general region of Earth - consider that the Atreides and Harkonnen homeworlds, Caladan and Geidi Prime, were each about 20 light years from Old Earth respectively. Assuming that the Dune series takes place in the Milky Way Galaxy, it can be clearly surmised that the Old Imperium remained situated in the Orion Arm (even though Frank Herbert calls it a "multigalactic empire"). Taking Frank Herbert's words into account, it is possible that the Imperium extended outside of this region of the Milky Way Galaxy, encompassing the entire Milky Way, and extending into the nearby Andromeda Galaxy (such as Tupile, or the Ixian colony that Leto II discovered through prescient vision), with only the most prominent planets of the pre-Scattering Imperium being in the Orion Arm. The Scattering changed all this, however - the people of the Scattering not only spread throughout the Milky Way Galaxy, but made fold-space jumps to other galaxies, such as Andromeda. In this way, people lived too far and wide to be governed by a single prescient force, as God-Emperor Leto II had intended. This, combined with the prescience-cloaking genes spread by Siona Atreides' descendants, achieved Leto II's Golden Path.