Extra-Universal Travel is the process of tunneling through dimensions into another universe. It is a large power consuming device that requires massive amounts of energy that are only able to be produced by highly advanced civilizations.
To this date only four civilizations are confirmed to have this technology, the Arkhangelsk Empire, Precursor, Architects, and the Paracytill. Two other civilizations are speculated to have the ability the Ancients and the Celestials. Today's extra-universal drives are more efficient than ever but still use the amount of energy equal to 100,000 of the largest stars.
History[]
Early History[]
Before the Arkhangelsk Empire it is clear that both the Precursor and the Architects developed the ability to travel between universes. Scientists theorize that it is highly similar to modern day extra-universal travel.