Dimensional transference, possibly also known as a black light explosion (if that was the only cause), was a theory that related to the stability of the universe. Some scientists believed that a black light explosion could cause a chain reaction that would spread until all matter in the galaxy was exhausted. Others believed the instability would spread to consume the entire universe.
Drathro nearly allowed his black light convertor to overload as the Sixth Doctor had told him the event was unique, but this was prevented. Seemingly there was never an explosion in the history of the universe.
The Seventh Doctor told Kadiatu Lethbridge-Stewart she could escape 1871 by diving her shuttle into the sun. When she hit a hot enough section of chronosphere, the temperature should trigger dimensional transference; effectively, an unlimited power source to let her keep making jumps in time. (PROSE: Set Piece)