Conceptual representation of the opening to a wormhole moving through a nebula. A wormhole (or Einstein-Rosen bridge) is a theoretical 'tunnel' through spacetime, allowed by the theory of general relativity. In principle, a wormhole connects two regions in the universe - or two different regions in space as well as time. An object entering the wormhole at one end might emerge in a very different region of the cosmos, an arbitrary distance from the start point and/or at a totally different time. As such, wormholes seem to permit faster-than-light travel. Nobody has every detected a wormhole and it is highly possible that they may exist merely as mathematical constructs rather than actual physical phenomena