a black hole isn't necessarily a hole in space but a dense mass and the visible vortex effect often associated with black holes is merely the accretion disk of visible matter being drawn toward it. Decker's line is most likely to inform that it was probably a wormhole that Voyager 6 entered, although the intense gravity of a black hole does warp the fabric of spacetime. The setting of the television series Star Trek: Deep Space Nine is a space station, Deep Space 9, located near the artificially-created Bajoran wormhole. This wormhole is unique in the Star Trek universe because of its stability. In an earlier episode of Star Trek: The Next Generation it was established that wormholes are generally unstable on one or both ends – either the end(s) move erratically or they do not open reliably. The Bajoran wormhole is stationary on both ends and opens consistently. It provides passage to the distant Gamma Quadrant, opening a gate to starships that extends far beyond the reach normally attainable, is the source of a severe threat to the Alpha Quadrant from an empire called the Dominion, and is home to a group of non-physical life forms which make contact with Commander Benjamin Sisko and have also interacted with the Bajorans in the past. Discovered at the start of the series, the existence of the wormhole and the various consequences of its discovery elevate the strategic importance of the space station and is a major factor in most of the overarching plots over the course of the series. In Star Trek: Voyager, in episode "Counterpoint", an alien scientist explains that the term wormhole is often used as a layman's term and describes various spatial anomalies. Examples for those wormholes in Star Trek are intermittent cyclical vortex, interspatial fissure, interspatial flexure or spatial flexure in episode "Q2" respectively spatial vortex in episode "Night". In the episode "Inside Man" an artificially created wormhole was named geodesic fold. In the 2009 Star Trek film, red matter is used to create artificial black holes. A large one acts a conduit between spacetime and sends Spock and Nero back in time. Doctor Who The Rift which appears in the long-running British science-fiction series Doctor Who and its spin-off Torchwood is a wormhole. One of its mouths is located in Cardiff Bay, Wales and the other floats freely throughout space-time. It is the central plot device