Asked by: Stuart Laws, by email
Some physicists have attempted to combine quantum mechanics with the General Theory of Relativity and concluded that black holes may not contain a ‘singularity’, the point at which density becomes infinite. This would open up the possibility that black holes are shortcuts to other universes. Actual tunnels through space-time, called ‘wormholes’, may be a better bet for traversing between universes. But although they’re predicted by Einstein’s theories, no wormholes have yet been discovered, and there are doubts that they could occur naturally at all.