Underspace

From Earth Central

Underspace (or U-Space) is a bizarre dimension that forms the basis of much polity technology, notably runcibles, space travel, and interstellar communication. Humanity began exploiting underspace in the 22nd century, although real progress in this area was only made in 2190, when Skaidon interfaced with AI and discovered runcible technology and more advanced underspace engines. The physics on which underspace operates is extremely complicated, and only fully understood by Polity AIs (although cored Prador are also used to operate U-Space engines).

Underspace remains the basis of all Polity interstellar travel and communication; all interstellar starships use U-Space engines for faster-than-light travel, allowing a distance of one light year to be travelled in 1-2 days in Polity Agent (travel across greater distances, however, can still take years). The speed of underspace travel is affected by "tides" in underspace (a starship entering during an optimal "tide" may reach its destination sooner than a starship entering earler under less favourable conditions). It can also be stopped using USERs (Underspace Interference Emitters) which create disturbances in underspace which prevent all but the most powerful interstellar vessels from crossing affected regions. Runcibles also make use of underspace, in a manner only AIs fully understand.

Underspace can also be used for time travel, but this normally yields extremely destructive results.