Wormholes can be found at the edge of every sector. Space is folded here in a way that allows movement of ships between sectors that are otherwise far removed. Wormholes are often surrounded by ambushing pirates waiting for their prey - take care when approaching one! If you encounter a wormhole that leads nowhere, don't be alarmed - science has simply not yet found a way to open it.
To jump through a wormhole, simply click on Jump to destination-sector in the Commands window. At the beginning, a wormhole jump will cost you over 20 APs. This value will decrease if you gain maneuver skill.