I know that folding spacetime is completely possible, and i'm pretty sure that the answer i'm looking for is in Einstein's field equations. I just don't know enough about tensor calculus (yet) to figure this out for myself. So my question: how much energy is required to completely fold a certain portion of spacetime? for example, how much energy would be required to fold enough spacetime to travel 1 lightyear. I know cosmic strings have quite a bit of energy, and that if two cross just right we think that they will have enough energy to fold spacetime completely. If the answer is really in the field equations, could someone please go step by step? like i said, im not that familiar with tensor calculus yet but this question is really starting to bug me.