What are worm holes?
A worm hole is a particular solution to Einstein’s relativistic equation for gravity in which two parts of space may be joined together. Unlike black holes, they have no internal singularities, at least in the vacuum solution, but certain rotating Kerr-type black holes may serve the same worm hole-like function. In relativity, all world lines either start on a singularity or end on one. The only way to ensure this kind of condition in rotating Kerr black holes is to make certain that when a world line passes from large distances to zero and extend to negative radial distances. For Schwarzschild black holes, all world lines entering the event horizon absolutely must terminate on the singularity at R = 0. for Kerr black holes, the singularity is avoidable, and these other space-times required for completing the world lines in this way can be reached, at least mathematically, by a single world line from our own space time. This is sometimes called the traversable Kerr worm hole solution.
