More Physics Questions Back to Ask the Experts Richard F. Holman is a professor of physics at Carnegie Mellon University. The first wormhole-like solutions were found by studying the mathematical solution for black holes. The throat is a dynamical object attached to the two holes that pinches off extremely quickly into a narrow link between them. This property goes back to the usual statement that if one could travel faster than light, that would imply that we could communicate with the past. The question now arises of whether it would be possible to actually construct a wormhole and move it around in such a way that it would become a usable time machine.
Wormhole geometries are inherently unstable.
The only material that can be used to stabilize them against pinching off is material having negative energy density, at least in some reference frame. No classical matter can do this, but it is possible that quantum fluctuations in various fields might be able to. This is known as the Chronology Protection Conjecture. Wormholes are great theoretical fun, and are seemingly valid solutions of the Einstein equations. There is, however, no experimental evidence for them.