Centauri Dreams recently examined wormholes and their possible survival from the early universe through the mechanism of a negative mass cosmic string. But what exactly is a cosmic string? Here’s Lawrence Krauss on the subject:

“During a phase transition in materials — as when water boils, say, or freezes, the configuration of the material’s constituent particles changes. When water freezes, it forms a crystalline structure. As crystals aligned in various distances grow, they can meet to form random lines, which create the patterns that looks so pretty on a window in the winter. During a phase transition in the early universe, the configuration of matter, radiation, and empty space (which, I remind you, can carry energy) changes, too. Sometimes during these transitions, various regions of the universe relax into different configurations. As these configurations grow, they too can eventually meet — sometimes at a point, and sometimes along a line, marking a boundary between the regions. Energy becomes trapped in this boundary line, and it forms what we call a cosmic string.

“We have no idea whether cosmic strings actually were created in the early universe, but if they were and lasted up to the present time they could produce some fascinating effects. They would be infinitesimally thin — thinner than a proton — yet the mass density they carry would be enormous, up to a million million tons per centimeter. They might form the seeds around which matter collapses to form galaxies, for example. They would also ‘vibrate,’ producing not subspace harmonics but gravitational waves. Indeed, we may well detect the gravitational wave signature of a cosmic string before we ever directly observe the string itself.”

From The Physics of Star Trek (New York: HarperCollins, 1995), pp. 149-150.

Of course, what Landis, Forward and the other authors of the paper “Natural Wormholes as Gravitational Lenses” were talking about was not just a cosmic string, but one possessing negative mass, and it would have to wrap itself around a wormhole in order to stabilize it so it could survive to the present time. Do such structures exist? If so, it is possible that advances in both space-based and ground astronomy will eventually prove the point, but even then, we’ll be left to speculate about where or when such a wormhole might lead.