One theory of time travel is that space is six-dimensional and so therefore can't be grasped fully by our primitive three-dimensional optical receptors(i.e. eyes). In this case, space can exist in many possible shapes. One example: Say that space is shaped as a cone. Use a pizza for a visual model; cut one slice out of the pizza and touch cut edge to cut edge.....notice the cone shape? Now, the distance around the upper edge is shorter than the distance to the point of the cone and back. In theory, if one could travel instead of the full distance the "folded distance", one would arrive at the destination before the follower of the other path.