Wormholes are standard fare in contemporary Science Fiction. The movie Stargate and its syndicated television spin-off series Stargate SG-1 were predicated on the idea that an advanced race of humans (the Ancients) were able to build a network of portals each of which was capable of establishing a stable wormhole to any other portal in the galaxy. This capability made it possible for people to travel from one side of the galaxy to the other in just a few seconds. The voyagers of Stargate SG-1 even discovered how to use the portal system to travel between galaxies.
A wormhole is a rip in space and time. Einstein's General Theory of Relativity allows for the possibility of wormholes. And given that there are roughly 10500 possible formulations of string theory it seems reasonable to assume that at least some variations would allow for the possibility of stable wormholes. From a purely mathematical point of view, such disturbances may come in many sizes and forms. They might be infinitesimal; they might span the length of a galaxy or of the universe itself. They might be shaped like a pipe with two distinct ends, or they might fork into two or more separate paths. They might not even have anything even remotely like a path at all; they might just open into a dead end nowhere with no possible avenue of exit.
There is no known natural process which might give rise to a wormhole. A few such processes have been hypothesized, but there is no evidence that any of them actually occur in nature. There are really only two ways that a wormhole might conceivably be used for interstellar travel. The first is to encounter a naturally occurring stable wormhole with one terminus at or near one's preferred point of departure and the other, single terminus near the preferred destination. Aside from the problem of locating such a phenomenon there is the none too trivial problem of trying to determine the location of the remote terminus from the features which are observable at the local terminus. That would only be possible if there were some well known features, such as nebulae or constellations, that were readily identifiable through the local terminus. That seems very unlikely. In the absence of such points of reference a traveler of the wormhole would simply be launching into the unknown and would wind up somewhere else, but not necessarily somewhere with a known location relative to the traveler's point of origin. That doesn't seem like a very useful form of travel.
The second possibility is that an advanced civilization might find a way to build machines that are capable of creating stable wormholes between two fixed endpoints. It seems unlikely that such machines could be built to establish a wormhole from only one endpoint. That is, the idea of opening a wormhole to a distant location seems to require having a machine at each end-- one to act as the point of origin and the other to act as the destination endpoint. And that means that such a system would require that members of the proposed advanced civilization must have traveled to each endpoint to install a wormhole opening machine. That is precisely the model that was adopted in the movie Stargate. The Ancients seeded the galaxy with millions of machines, each of which could serve as either a point of origin or a terminus. To establish a stable wormhole, the traveler would tell the machine at his point of origin the location of the machine at his preferred terminus, and the two machines would open a wormhole between them. This was done with a device known as a “Dial Home Device,” or DHD. But the point here is that to build such a system of gates one would have to travel to every preferred endpoint to install a wormhole-generating machine first. And that means that the advanced civilization would need to have a way to travel fairly rapidly from one part of the galaxy to another without the aid of a wormhole. We'll discuss that possibility in another topic, but the point here is that building a system of wormhole-generating gates depends on the ability to travel quickly from one part of the galaxy to another without the benefit of a wormhole.
Is it actually feasible to build a wormhole-opening machine? Let's forget about the presumed requirement that such a machine would have to employ some form of exotic matter to be able to keep the wormhole open and talk exclusively about the power requirements. One estimate says that it would take more power than could be provided by the Sun over its entire lifetime to open a wormhole that might be longer than a few millimeters. That just doesn't seem very practical. There are, of course, larger stars that generate far more power than our Sun; perhaps one of them could be used as a power source. But that would mean that we would need a method of capturing a large percentage of the power generated by a much larger star-- and that is a highly non-trivial problem to solve.
Another possibility is that we could try to harness the power of a pulsar. Such stars are generally smaller than our Sun, and they generate immense electromagnetic fields. A station in orbit around such a star might be capable of capturing part of the energy of the star by simply building an immense antenna. But shielding such a station from the harmful effects of the pulsar's radiation would be prohibitively expensive.
All in all a system of gates such as those envisioned in the Stargate SG-1 television series seems highly infeasible. It made for great adventure telling, but it is highly unlikely that any such devices would ever actually be built.
Copyright (c) 2011 by David S. Moore. All rights reserved.