The term "stargate" was first coined by Arthur C. Clarke in his novel 2001: A Space Odyssey, and was at least one function of the mysterious black monoliths found in his seminal novels. Today the concept of stargates are most famously known from the Stargate movie and TV series. Stargate-like systems have also been used in the Hyperion novels by Dan Simmons, the novel A Million Open Doors by John Barnes, the anime series Iria: Zeiram The Animation, and the science fiction wargame Starcraft, among others.
A stargate is a means of traveling interstellar distances without the need of a spaceship. It is perhaps the ultimate form of interstellar travel. One dials up a destination, steps through the gate, and you end up on another planet light years, or maybe even galaxies, away. Whereas standard wormholes created permanent tunnels through space/time that only have two openings, a stargate system allows the user to travel to any number of destinations from a single departure point.
One aspect all stargate systems seem to have no matter their operating principle is the necessity of both a transmission station and a receiving station, the same device usually acting as both. In many ways stargates superficially resemble closed teleportation systems, only with reaches of interstellar, or even intergalactic, distance. See the article on Teleport Drives for further details.
The availability of stargates to interstellar civilizations would have major implications. Societies where interstellar ships are the predominant form of travel are usually envisioned as networks of separate cultures, like islands connected by boats, or even like towns connected by a highway system. Even though worlds may share common characteristics or heritage, they are still very much separate entities from each other, with their own ideas and traditions.
When other worlds are only a short walk away, however, interstellar civilizations can achieve a level of homogeneity previously impossible. All worlds connected to the stargate network can easily become subsumed into the mainstream interstellar metaculture. This is the case in both the Gua’uld of the Stargate universe and the Hegemony/WorldWeb of the Hyperion universe. A culture trying to resist such assimilation is the main theme in John Barne’s novel A Million Open Doors.
One of the main difficulties after the technology is developed is actually establishing the stargates and the stargate network on the various different worlds of the building civilization, which could number hundreds, thousands, or even millions. This is much more complicated than just building bridges between islands. All destinations are moving targets (planets spin and revolve about their parent stars, which in turn move about the center of the galaxy.) Not only do the multitude of such devices have to be physically built, but a dynamic multi-dimensional coordinate and navigation system would have to be developed for them to remain active. Standard starships would also still be needed to transport or construct stargates at new destinations.
These are the stargates used in the movie Stargate and the TV series Stargate SG-1 and Stargate Atlantis, named after the race in that fictional universe (also known as the "Ancients") who created them. These are the best examples of stargates as the concept exists in the popular imagination.
The Stargate system itself consists of three major components: a potent power source (usually a "naquadah" generator housed underground, but nuclear reactors on Earth are also used), a dialing device (to determine the general destination of the wormhole using a three-dimensional, seven coordinate system), and the wormhole-generating device itself, in this case in the form of a large 30 foot-wide ring.
Alteran Stargates create temporary wormholes between one gate and another. Its assumed that the wormholes created are similar in general to the Standard Wormholes described in the Wormholes article in the FTL section, only access to them is highly "customized" by the machines for practical travel purposes and tactical convenience. For example, a standard wormhole should allow travel both ways through it once established, but the Stargates allow travel only from the activating gate to the receiving gate, blocking any traffic that tries to go back through the other way.
How exactly the gates create these wormholes is never really addressed. There seems to be no loss of matter involved, only the influx of large amounts of energy. Since its specifically stated that the wormholes are created as opposed to mined from quantum foam, one might conclude that they use the energy input into them to create quantum-level kugelblitzes, singularities formed solely by the intense concentration of energy. The gates must also use that same energy input to create the negative energy needed to pry open the kugelblitz singularity to form the wormhole needed. This process would of course be insanely complex and require a very intimate knowledge of space/time topology and quantum mechanics, especially given the relatively low energy levels used to create these wormholes, hence the Stargates’ extremely high Tech Level.
In standard wormhole formation, the wormhole mouth can exist just fine independent of a gate. The receiving stargate may be just there to "guide" the wormhole mouth to the proper destination for travel convenience. Being able to precisely place a wormhole mouth at a moving target in three dimensional space across light-years of distance would be a feat of exact calibration that would be difficult to imagine. Therefore the receiving gate may just function similarly to runway lights for airplanes; it guides the wormhole in from higher-dimensional space to a precise three-dimensional "landing" at its location.
As stated, the Alteran Stargates seem to "customize" travel through the wormholes for various reasons. Besides the one-way feature, the stargates also use "subspace buffers" to make sure only whole objects are transferred through the gate. Any object being pushed through the gate is redirected to one of these buffers, where it is held in temporal suspension until it completely passes through the transfer horizon. Only after that is it sent through the wormhole to the destination gate. An object can still be pulled back out of the gate as long as it has not fully entered one of these buffers. What exactly constitutes subspace here is left extremely vague, and why it would be able to stop the temporal clock of objects entering them is unknown.
In earlier seasons of Stargate SG-1, they likened the stargates in some ways to Star Trek’s transporter, saying that the traveler was "dematerialized" in the subspace buffer and then "reconstructed" once on the other side. However, like with the Enterprise’s original transporter concept, that would mean you would die every time you entered the gate, and an exact copy of you--but not you--would be reconstructed on the other side. The show’s creators have since seemed to downplay that interpretation of the Stargates’ operation, and now vaguely suggest that the object remains whole in the subspace buffer the entire time its held there.
The Warp Gates seen in the science fiction computer game Starcraft seem to be conceptually similar to the Alteran Stargates.
The Farcaster network was one of the essential features of Dan Simmon’s classic Hyperion novels, the first two especially. It takes the concept of a stargate even further. Whereas Alteran Stargates are highly-prized, ultra-tech artifacts coveted and guarded by the owning civilizations, in the Hyperion universe they are so ubiquitous as to be living room conveniences. A number of works, such as John Barnes’ A Million Open Doors and the Anime Iria: Zeiram The Animation use similar from-the-living-room-to-distant-worlds model for stargates, but with not quite the casual ease shown in Dan Simmons’ Hegemony/WorldWeb civilization.
In orbit about each planet of the World Web, a particular kind of quantum singularity would be constructed, one that tapped into the "Void Which Binds" a subspace-like dimensionless void of near-unlimited quantum potential. The exact nature of the Void Which Binds is left vague. In some theories of cosmology, however, its contemplated that the Big Bang may have given birth to many more dimensions that the ones we’re familiar with. Depending on the theory, these "extra" dimensions may number ten or eleven, or even be as many as twenty-six. The reason why we don’t perceive these dimensions is that all but four of them "collapsed" to the planck-scale level of the universe within nanoseconds after the moment of creation. They are still present and still suffuse the cosmos much like our more familiar dimensions of space and time, but are completely inaccessible unless one is able to reach down and manipulate the planck-scale level of existence.
The Void Which Binds may be one of these collapsed dimensions, a quantum realm of no space or time which nevertheless reaches every point in the cosmos past and future.
Once a singularity was constructed, millions of farcaster portals could be potentially constructed on and around the planet, using the rip in space/time provided by the singularity. From what is described in the novel, the singularity seems to create folds in space/time in close proximity to itself at the farcaster portal locations, folds that connect from the planet to destinations light-years distant through the planck-scale non-dimension of the Void Which Binds. The connection apparently remains stable with little maintenance energy needed as long as the portal and the mother singularity remain intact.
Enormous farcaster portals were placed in orbit to facilitate large transport of goods, but large portals were also placed in cities, much like tunnel entrances along a road. Though the portals were usually "locked" on one destination, they could be shifted to other destinations if desired.
On large and affluent worlds, there would be farcaster portals everywhere. Malls would have stores, each on different worlds, with farcaster portals built into the store entrances. The wealthy often had multi-world mansions, with different rooms on different worlds. It was a common occurrence for one or more people in a family to live on one world and commute to work on another through a neighborhood farcaster connection.
The Farcaster system represents manipulating singularities, collapsed dimensional spaces, and folds in the fabric of time and space with extreme precision and miraculous ease, hence its just a smidgen below the god-like technology levels.
In The Media:
The Stargate Movie
Stargate SG-1 and Stargate Atlantis TV series
Starcraft computer game
Iria:Zeiram The Animation anime
The Hyperion series by Dan Simmons
A Million Open Doors by John Barnes
Cosmic Wormholes By Paul Halpern
In Search of The Big Bang, In Search Of Schroedinger’s Cat, and Schroedinger’s Kitten by John Gribbin
Hyperspace: A Scientific Odyssey Through Parallel Universes, Time Warps, and the 10th Dimension by Michio Kaku
On The Web: