The Enterprise trapped in a space-time continuum.
Space-time continuum is a term used to describe any universe, dimension or reality which exists independently and is self-contained, sometimes having its own set of physical laws.
In 2268, the Starship Enterprise accidentally entered a space-time continuum when passing through the negative energy barrier at the edge of the galaxy at a high warp factor. Lacking any reference point with which to determine a course back to the Milky Way, the Enterprise was only able to return with the assistance of Kollos, whose species possessed a high level of navigational expertise. (TOS: "Is There in Truth No Beauty?")