Wormholes are subspace shortcuts. A wormhole allows starships to cover great distances in a single move, but if the wormhole does not have an endpoint, the starships will be lost.
Finding wormholes with an endpoint can only be accomplished with trial-and-error.
On the strategic map, wormholes are identified only by their sector - no distinction is made between wormholes with an endpoint and those without.
Any ship that successfully passes through a wormhole will be set to 'Avoid' on the next turn.