Krasnikov tube

A Krasnikov tube is a mechanism for faster than light space travel involving the warping of spacetime into permanent superluminal tunnels. The resulting structure is analogous to a wormhole with the endpoints displaced in time as well as space. The tube is a distortion of spacetime that can be created in the wake of travel near the speed of light. The tube allows for a return trip that takes travelers back to the time right after they left. Experiencing the effect requires that the traveler race along the tube at speeds close to that of light.