Dark Shift is the colloquial term for the high power setting of the Zero Point Energy Drives or ZPE Drives. The ZPE drive was the universal mode of long distance space transport. It is a machine that gathers Zero Point Energy from the limitless background radiation in the vacuum of space in order to power them through space.
The high power mode known as "Dark Shift" is when the ship's drive gains so much power that the strength of the field used to allow the acceleration causes the ship to slip out of normal space and into the dark matter streams that ran like a maze throughout the universe making up most of its unseen mass.
In the dark matter streams the ships traveled at such velocity that they could cover a light year in ten minutes, however due to the fact that in the dark matter streams time moves much slower when the ships emerge only minute or so will have passed in the real world.
LOOK INTO DARK ENERGY THEOREM