[[Image:SG1stargate.jpg|thumb|300px|A typical [[Milky Way]] Stargate.]]
'''Stargates''' are large, ring-shaped devices in the ''[[Stargate]]'' [[science fiction]] [[fictional universe|universe]] that utilize advanced technology for nearly instantaneous personal travel across the vast distances of space. These devices were first seen in fiction with the 1994 film ''[[Stargate (film)|Stargate]]'', directed by [[Roland Emmerich]], and then subsequently in the TV series ''[[Stargate SG-1]]'' and ''[[Stargate Atlantis]]'' (as well as the animated series ''[[Stargate Infinity]]''). The Stargate is the central [[plot generator]] of these productions, allowing for stories focused on a small team of [[protagonist]]s exploring other planets and meeting other races on foot, rather than the more prevalent, grandiose "[[space opera]]" of interstellar [[starship]]s seen elsewhere in science fiction.
Stargates are marked out by nine "chevrons" spaced equally around their circumference, and roughly 39 symbols displayed on an inner ring[[[MGM]] Official Website for ''[[Stargate SG-1]]'', trivia, URL: http://www.stargatesg1.com/stargatehb.html]. Although typically 22 feet (6.7 m) in diameter and made of a fictional heavy mineral called "[[Fictional materials in the Stargate universe#Naqahdah|Naqahdah]]" (''see also: [[#Making of the Stargate|actual constitution]]''), the gates are almost always seen standing vertically.
In the mythology of the [[canon (fiction)|canon]], their creators were an alien race known as the [[Ancient (Stargate)|Ancients]][[[MGM]] Official Website for ''[[Stargate SG-1]]'', trivia, URL: http://www.stargatesg1.com/stargatehb.html] (properly, the Alterans[{{sgcite|Avalon|show=ref}}| [http://wiki.stargate-sg1-solutions.com/index.php/9.01_%22Avalon_Part_1%22_Transcript Transcript Part I], [http://wiki.stargate-sg1-solutions.com/index.php/9.02_%22Avalon_Part_2%22_Transcript Transcript Part II]]), who scattered them on habitable planets throughout the [[Milky Way]] and other galaxies, millions of years ago. Collectively, these comprise what is often called the "Stargate Network", which facilitates travel throughout the cosmos. Stargates are present on many planets but, to primitive peoples, they are no more than relics carrying associations of the divine and sacred, or of fear, as evidenced by such names as "Ring of the Gods"[Several early ''SG-1'' episodes, e.g. {{sgcite|The First Commandment|1}} | [http://wiki.stargate-sg1-solutions.com/index.php/1.06_%22The_First_Commandment%22_Transcript#Transcript Transcript]] and "Circle of Darkness"[{{cite episode|title=Demons| episodelink=Demons (Stargate SG-1)| series=Stargate SG-1| serieslink=Stargate SG-1}} | [http://www.stargatefan.com/scripts/s3/demons.html Transcript]]. Thus the plot of ''Stargate'' effectively begins when the [[United States Air Force|US Air Force]] discovers how to use the device discovered on Earth[''[[Stargate (film)|Stargate]]'' (1994) | [http://www.gateworld.net/movies/01.shtml Producer comments]].
==Name and origin==
The idea of the Stargate was invented by the writers of the original [[Stargate (film)|feature film]] of the same title, [[Dean Devlin]] and [[Roland Emmerich]]. Similar devices have been seen in previous fiction, but the complete conception of a Stargate, as seen in the [[Stargate]] canon, is quite original — though there has been contention as to whether they plagiarised the idea from a previous script submission.[[[Internet Movie Database]] trivia, URL: http://www.imdb.com/title/tt0111282/trivia] The name was a logical choice ("gate to the stars"), but in retrospect has caused the series and film to be mistaken for the unrelated series ''[[Star Trek]]'' and ''[[Star Wars]]''. The Stargate was further developed conceptually by the creators of the spin-off TV series ''[[Stargate SG-1]]'', [[Brad Wright]] and [[Jonathan Glassner]].
[[Image:Worm3.jpg|thumb|Analogy of a wormhole]]
The concept of a Stargate is based heavily in [[theoretical physics]], particularly that of [[black hole]]s and [[wormhole]]s. Some scientists believe that a wormhole is a warping of [[spacetime]] causing space to become "folded" and can allow for "shortcuts" through space. This view is not widely held to be true,[{{cite web | author=Krasnikov, Serguei | title=The quantum inequalities do not forbid spacetime shortcuts| work=arXiv eprint server | url=http://arxiv.org/abs/gr-qc/0207057 | accessdate=August 12| accessyear=2005 }}] especially of travel for human beings, as such wormholes would most likely be created by black holes, the [[gravitation|gravity]] of which would destroy any potential traveller.[{{cite web| url=http://cosmology.berkeley.edu/Education/BHfaq.html| title=Black Holes FAQ (Frequently Asked Questions) List| first=Ted| last=Bunn| accessdate=2006-03-25}}] A Stargate creates an "artificial", controlled black hole of sorts, yielding a "stable wormhole".
The idea of a "[[Portal (fiction)|portal]]" for travellers has been seen often throughout the history of both [[fantasy]] and [[science fiction]], often taking a similar form, a device or magical object shaped as a [[regular polygon|regular]] or [[Enriques-Kodaira classification|irregular]] [[Closed manifold|closed geometric form]] filled with a [[water]]-like, [[Ripple (physics)|rippling]] [[puddle]] that represents the boundary point between two locations (''see below section: [[#Common envisioning|common envisioning]]''). The Stargate picks up on this conception, emphasising the "watery puddle" for the sake of an [[Extraterrestrial life in culture|alien]] mystique, and explaining it all in terms of advanced technology.
The origins of the Stargates are expounded upon in great detail in ''[[Stargate SG-1]]'', the follow-up [[television program|TV series]] to the film, which involves a rich background of alien races, each of which have discovered the Stargates separately and grown around them. The Alterans, (also known as the Ancients), who built the gates, appear to have called them ''Astria Porta''. The [[Jaffa (Stargate)|Jaffa]] and [[Goa'uld]] call them the ''Chaapa'ai'', and the English word "Stargate" is supposedly a direct [[calque]] of this word. It seems that ''Chaapa'ai'' is itself a calque of ''Astria Porta''. In the Pegasus galaxy, villagers know them as ''Rings of the Ancestors'' and variations thereof. They are also referred to as "the ring", "the [[annulus]]", or "the gate".
== Operation ==
The film ''Stargate'' rushed very quickly over how a Stargate actually works and is operated, but the subsequent TV shows go into this area in a great amount of detail. In ''SG-1'' it is explained that the Stargate generates a [[wormhole]] between itself and a remote gate by being supplied with a threshold amount of raw electricity, and that the destination gate is singled out by a process known as "dialing", described below. Objects in transit are broken down into their individual [[element]]al components and then reconstructed on the other side, yet walking through a Stargate is superficially no different from stepping through a doorway.
=== Dialing ===
[[Image:Stargatesg1diallingcomputer.jpg|thumb|The [[SGC]]'s Dialing Computer compiling an address.]]
Each location served by a Stargate has its own unique "address", which is a combination of six or more non-repeating["seven symbols chosen from a pool of 38 non-repeating candidates, that's about 63 billion possible combinations." {{cite episode| title=Avenger 2.0| episodelink=Avenger 2.0 (Stargate SG-1)| series=Stargate SG-1| serieslink=Stargate SG-1}} | [http://wiki.stargate-sg1-solutions.com/index.php/7.09_%22Avenger_2.0%22_Transcript Transcript]] symbols appearing on the dialing Stargate. By "dialing" these symbols in the correct order, the traveler can select a destination.
The show is consistent with the mechanics of address-dialing. The process involves associating a unique symbol of the inner ring to each of at least the first seven of the chevrons on the outer circumference. The main "address" is invariably dialed first, followed by the gate's "origin" symbol, which acts as the final trigger for the completion of the address sequence. As each symbol is dialed, the chevron is said to "engage" and usually responds by lighting up or moving. When the final symbol of an address is dialed, that chevron is said to "lock" and the wormhole opens (this terminology is arbitrary and often interchangeable, but preferred by the recurring character [[Walter Harriman]]). If the address is incorrect or does not correspond to an existing or otherwise functional Stargate, the last chevron will not lock, and all of the chevrons will disengage.
There are 3 ways that a Stargate has been seen to be dialed:
*'''With a Dial Home Device'''
The most common method is with a [[Dial-Home Device]] (DHD), a control console usually found accompanying a Stargate. The console has a button for each of the symbols on its accompanying gate, and travellers use these to compile their address. The gate is then powered by the DHD itself. [[Puddle jumper (Stargate)|Puddle Jumper]]s have an [[Puddle jumper (Stargate)#Puddle Jumper DHD|on-board DHD panel]], which functions as a [[remote control]] to the gate {{sgcite|Moebius|show=all}}.
*'''By Dialing Manually'''
If no dialling system is present, a user must manually select the address. On a Stargate of [[Milky Way]] design, this involves using sheer force to rotate the inner ring to select each of the seven symbols located on it (like rotating a colossal combination lock). A manual power-source is also required; the element the gate is composed of is described as a [[Superconductivity|superconductor]] to which electricity can be fed directly, and so lightning strikes have been shown to be minimally sufficient {{sgcite|The Torment of Tantalus|1|show=all}}. Pegasus Galaxy Stargates do not have a movable ring and so manually dialing these may be impossible.
*'''With an Alternate Dialer'''
If no DHD is present, travellers will be forced to emulate one. The technology within a DHD is described as far superceding Earth technology, making DHD emulation particularly difficult. Examples of alternate dialers include:
**''The [[Stargate Command]] Dialing Computer:'' this is the technology built in the film by humans to make use of the gate. Essentially, it operates on the same principle as manual dialing, except the dialing computer controls electric motors that move the ring around; in normal manual dialing, the ring would be moved by hand. This results in an acceptable rate of dialing, but is slower than most other methods.
**''The [[Atlantis (Stargate)|Atlantis]] Gate dialer:'' essentially a Puddle Jumper DHD; however, it appears to have extra features, like blocking out certain gate addresses ("[[Before I Sleep (Stargate Atlantis)|Before I Sleep]]").
**''Remote dialers:'' these can be held in the hand or worn on the wrist, and have been used by the [[Goa'uld]] and [[Asgard (Stargate)|Asgard]] in various episodes, as well as by the character Cassandra in the episode "[[1969 (Stargate SG-1)|1969]]". The [[Nox (Stargate)|Nox]] character Lya was seemingly able to engage the Stargate through her own powers, but perhaps had an unseen remote dialer ("[[Enigma (Stargate SG-1)|Enigma]]").
=== Addresses ===
[[Image:StargateCoordinates.png|thumb|right|This diagram illustrates [[Daniel Jackson|Dr. Jackson]]'s theory of how Stargate symbols translate to physical coordinates.]]
The symbols used to comprise addresses are actually images of [[constellation]]s. By identifying six constellations in space, a single point can be extrapolated that corresponds to the destination desired[''[[Stargate (film)|Stargate]] (1999)]. It is assumed by the show that this is enough to identify the position of any Stargate within a galaxy. The symbols dialed are often referred to as "coordinates", and are written as an ordered string; for example, this is the address used in the show for the planet [[Abydos (Stargate)|Abydos]]: {{Milky Way Gate Address|27|07|15|32|12|30|pixelwidth=16|openbracket=|closebracket=}}.
[[Image:Seventh chevron.jpg|thumb|left|The seventh chevron.]]
Eight-symbol addresses were introduced in the episode {{sgcite|The Fifth Race|1}}, to connect to Stargates in a different galaxy. The eighth symbol acts as a type of "area code"[{{cite episode|episodelink=The Fifth Race (Stargate SG-1)| title=The Fifth Race| series=Stargate SG-1| serieslink=Stargate SG-1}} | [http://wiki.stargate-sg1-solutions.com/index.php/2.16_%22The_Fifth_Race%22_Transcript Transcript]]. Such connections, in comparison to seven symbol codes, required substantially more energy to complete a functional wormhole — much more than any standard dialing method can provide. So far, a [[Zero Point Module|ZPM]] (Zero Point Module) or a power modulator based on Ancient technology[{{cite episode|episodelink=The Fifth Race (Stargate SG-1)| title=The Fifth Race| series=Stargate SG-1| serieslink=Stargate SG-1}}] are the only power sources shown to have been capable of initiating an intergalactic wormhole. However, an [[Atlantis (Stargate)|Atlantis]]-Earth wormhole powered by five [[naqahdah generator]]s was established for just over one second to allow a high-density data-burst to be transmitted (''[[Stargate Atlantis|Atlantis]]'': "[[Letters from Pegasus (Stargate Atlantis)|Letters from Pegasus]]") and the [[Ori (Stargate)|Ori]] have shown the capability to establish an intergalactic wormhole by tapping the energy extant in a black hole[{{cite episode|episodelink=Camelot (Stargate SG-1)| title=Camelot| series=Stargate SG-1| serieslink=Stargate SG-1}}| [http://wiki.stargate-sg1-solutions.com/index.php/9.20_%22Camelot_Part_2%22_Transcript Transcript]].
Nine-symbol addresses have never been dialed, and their purpose is as yet unknown. The eighth and ninth chevrons are so rarely used that Stargates are often seen with those two chevrons embedded within the stone platform that holds the gate upright (see the image at the top of this article). This has often led to the misconception that a Stargate only has seven chevrons.
=== Dial Home Device ===
[[Image:Dhd.jpg|thumb|A Dial-Home Device]]
{{Main|Dial-Home Device}}
The Dial-Home Device, almost always referred to as the "DHD" for short, is depicted as a pedestal-shaped device with a round inclined control panel on top, consisting of two concentric circles of "keys", and a translucent red hemisphere in the center; the keys represent the symbols on the rim of the Stargate and the central hemisphere serves as an "[[Carriage return|Enter]]" key to activate the Stargate once a destination has been dialed. The DHD also provides power for the Stargate and has been shown to include a complex programming interface that is not normally needed by the operator[{{sgcite|Home|A|show=ref}} | [http://www.moon-catchin.net/gatenoise/sgatranscripts/s1/109home.htm Transcript]]. One of the most basic and repeated axioms of [[Wormhole physics (Stargate)|Wormhole Physics]], the (fictionalised) field of study pioneered by [[Samantha Carter]], is that unless an extraordinary amount of energy is being generated at either end, a wormhole can only be maintained for 38 minutes at a time.
[[Image:Wormhole old.jpg|thumb|The classic-style wormhole.]]
The actual portal of a Stargate appears inside the inner ring when an address is correctly dialed. This has the appearance of a vertical [[puddle]] of water, called the [[event horizon]] by the show. In non-fictional parlance, an event horizon is the surface of a [[black hole]] through which one could pass into a ''theoretical'' wormhole; the magic of the Stargate technology is thus to form a [[spacetime]] distortion (wormhole) without the gravitational effects of a black hole. The wavering undulations characteristic of water are said to be "fluctuations in the event horizon"[{{cite episode|episodelink=Children of the Gods (Stargate SG-1)| title=Children of the Gods| series=Stargate SG-1| serieslink=Stargate SG-1}}| [http://wiki.stargate-sg1-solutions.com/index.php/1.01_%22Children_Of_The_Gods_Part_1%22_Transcript Transcript Part I], [http://wiki.stargate-sg1-solutions.com/index.php/1.02_%22Children_Of_The_Gods_Part_2%22_Transcript Transcript Part II]] according to [[Samantha Carter]]. This puddle may then be entered (usually accompanied by a water-like sound), and the traveller will emerge from a similar pool at the destination Stargate. The show makes it clear that transit is strictly one-way; the episode "[[A Hundred Days (Stargate SG-1)|A Hundred Days]]" demonstrates that matter attempting to enter an incoming wormhole is destroyed. The gate is meant to be entered from the same side as the "kawoosh"; the show has not demonstrated what happens when someone tries to enter from the wrong side.
[[Image:New wormhole.jpg|thumb|The new-style wormhole.]]
The show is ambiguous in how it displays wormhole travel. Transit is sometimes almost instantaneous, and other times it may last up to 20 seconds. Most commonly the process lasts about 3 seconds. Passage through a Stargate is usually accompanied by a visual effect of shooting through a tunnel in space, and it is unclear whether this is meant to be a [[Grammatical person|first person]] traveller's-eye-view representation, or just a visual aid. The former interpretation, though technically impossible (as a traveller's eyes are, along with the rest of his or her body, deconstructed into their individual atoms in transit), is often suggested by the show, as novice travellers often emerge from the gate trembling as if they've been on a "[[roller coaster]] ride"[{{cite episode|episodelink=Children of the Gods (Stargate SG-1)| title=Children of the Gods| series=Stargate SG-1| serieslink=Stargate SG-1}}], and the character [[Charles Kawalsky]] describes travel like "pull[ing] out of a simulated bombing run in an [[F-16 Fighting Falcon|F-16]] at eight plus [[Acceleration due to gravity|gee]]s"[{{cite episode|episodelink=Children of the Gods (Stargate SG-1)| title=Children of the Gods| series=Stargate SG-1| serieslink=Stargate SG-1}}]. The visual effect resembles a spinning wispy tube, and was in Season 9 (and the first season of ''[[Stargate Atlantis|Atlantis]]'') updated to resemble a misty tunnel lit by shooting rings of light.
== Complexities of function ==
Stargates are immensely complex, and are the masterworks of the Alteran race. Often through complete accident, some further function is discovered by [[SG-1]]. A detailed description of the further functionality of the Stargate is given below; you may wish to skip this section if you are only after an overview of the Stargate.
=== Secondary gates ===
[[Image:Antarctic gate.jpg|thumb|The "Antarctic Stargate", Earth's secondary gate]]
Some planets are known to possess "secondary" or "backup" Stargates. The second Stargate is normally inactive, with the primary Stargate receiving all incoming wormholes. If a Stargate experiences a power surge while an outgoing wormhole is open, the other end of the wormhole automatically "jumps" to the next closest gate in the network. In the case of a planet with two gates, the other inactive gate is used as the backup. On at least one occasion, a Stargate was hit by an energy weapon as [[SG-1]] team members were using it to return to Earth. This caused them to be transmitted to a second, previously unknown gate on Earth that was located beneath the ice of [[Antarctica]].[{{cite episode| episodelink=Solitudes (Stargate SG-1)| title=Solitudes| series=Stargate SG-1| serieslink=Stargate SG-1}} | [http://wiki.stargate-sg1-solutions.com/index.php/1.18_%22Solitudes%22_Transcript Transcript]] However, the ability to defer an incoming wormhole to a nearby gate appears to be something more than a failsafe, as it is seen as a defensive measure in the episode "[[Prototype (Stargate SG-1)|Prototype]]".
The [[Dial-Home Device]] (DHD) is apparently responsible for determining whether a Stargate is primary or secondary. The Russians, in their position of controlling the secondary gate, were able to use their DHD to override the American Stargate's (the SGC's) reception of incoming wormholes to retrieve their own returning Stargate exploration teams. In the absence of a DHD (as in the two-year period on Earth between the disconnection of the Russian gate and its rental to the United States), the primary gate is apparently determined by which gate has a power source attached to it.
=== Matter transmission ===
[[Image:event horizon emerge.jpg|thumb|People emerging from a Stargate's event horizon.]]
When an [[Physical body|object]] passes through the event horizon, it is not immediately transferred to the destination Stargate, but rather the portion that has passed through is dematerialised and held in some kind of [[Hyperspace (science fiction)|hyperspatial]] [[Buffer (computer science)|buffer]]. An object that hasn't completely passed through the event horizon may be pulled out again, and its atoms will rematerialise from the buffer as it is extracted. The gate does not begin transmitting an object until it has entirely passed through the event horizon. This ensures that only complete objects are transferred. If a Stargate is shut down while an object is halfway through, the portion that is already through the event horizon ceases to exist.
A Stargate transmits matter in [[Discrete mathematics|discrete unit]]s. Before an object is transmitted through the matter stream from the originating Stargate to its destination, the object must completely cross the event horizon of the wormhole. Matter travelling through a Stargate wormhole retains any [[kinetic energy]] it had while entering the event horizon, so a person running into one Stargate will hit the ground running upon emerging from another Stargate. Also, any matter that has entered the event horizon, but has not been transmitted through the wormhole, will remain in a state of suspension. This has been used to "store" people in medical need[{{cite episode| series=Stargate Atlantis| serieslink=Stargate Atlantis| episodelink=Thirty-Eight Minutes (Stargate Atlantis)| title=38 Minutes}} | [http://www.moon-catchin.net/gatenoise/sgatranscripts/s1/10438minutes.htm Transcript]], but the risk of premature Stargate shutdown makes this a dangerous maneuver.
Matter stuck in the hyperspatial buffer may be recoverable. Recovering a stored object requires creating an event horizon without connecting to a wormhole; in connecting, the unstable vortex ("kawoosh") wipes the buffer clean to receive new information.[{{cite episode| series=Stargate SG-1| serieslink=Stargate SG-1| episodelink=48 Hours (Stargate SG-1)| title= 48 Hours}} | [http://wiki.stargate-sg1-solutions.com/index.php/5.14_%2248_Hours%22_Transcript Transcript]]
The transmitting Stargate does not allow the air molecules of the local atmosphere to pass through. Doing so could be disastrous should a receiving gate be located in a vacuum. The gate also prevents water from passing through if it's submerged. There's a seeming inconsistency in the ''Stargate Atlantis'' Episode "Inferno", in which lava passed through the gate and would have emerged in the Atlantis gate room had the forcefield not be activated. This is explained in one episode by Carter[{{cite episode| series=Stargate SG-1| serieslink=Stargate SG-1| episodelink=Watergate (Stargate SG-1)| title= Watergate}} | [http://wiki.stargate-sg1-solutions.com/index.php/4.07_%22Watergate%22_Transcript Transcript]], saying that the Stargate differentiates between objects attempting to pass through the event horizon and things that would naturally exert pressure, such as water.
=== Gate obstruction ===
[[Image:Buried gate.jpg|thumb|A gate obstructed by means of burial]]
A wormhole is prevented from forming if a significant obstruction is present inside the Stargate's ring. Consequently, it is fairly common for Stargates to be semi-sealed or permanently sealed by burying them; this action invalidates that Stargate address. Another means of controlling travel through a Stargate is by placing a barrier a minuscule distance (less than two micrometres) from the event horizon, which allows wormholes to be formed but prevents the reconstitution of matter upon arrival through the gate. The [[Iris (Stargate)|Iris]] on the Earth Stargate and the Iris Shield on the [[Atlantis (Stargate)|Atlantis]] Stargate perform this function and are an effective defense while still allowing radio communication through the open wormhole. Iris-type barriers suppress the kawoosh. Several aliens, including the [[Asgard (Stargate)|Asgard]] and the [[Nox (Stargate)|Nox]] have demonstrated the ability to open a wormhole without the "kawoosh".
=== Power source ===
Power is always required to establish an outgoing wormhole, usually from the DHD, but any Stargate can receive a wormhole whether it has a power supply or not; the dialing gate is the one that supplies power to both. In a few cases, Stargates have been dialed "manually" when more sophisticated means were not available. This was accomplished by providing sufficient raw power to the gate and then rotating the symbol ring by hand to lock each chevron (e.g. "[[The Torment of Tantalus (Stargate SG-1)|The Torment of Tantalus]]" and "[[Prisoners (Stargate SG-1)|Prisoners]]"). Power can be fed directly into the [[Fictional materials in the Stargate universe#Naqahdah|Naqahdah]] that comprises the gate; a lightning strike has been shown to be sufficient.
The Stargate that establishes an outgoing wormhole determines how long the wormhole is held open, and can generally close the wormhole at will. There are inconsistencies in how this is portrayed in the series. Sometime the gate appears to stay open without anything passing through it — other times it snaps closed as soon as the last person has emerged.
=== Durability ===
[[Image:GateExplode.jpg|thumb|right|A Stargate intact at the centre of a [[Fictional materials in the Stargate universe#Naqahdriah|naqahdriah]]-enhanced nuclear blast.]]
The Stargates themselves are particularly resistant to damage or destruction: in one case, a Stargate survived a direct hit from a meteor,[{{cite episode| episodelink=A Hundred Days (Stargate SG-1)| title=A Hundred Days| series=Stargate SG-1| serieslink=Stargate SG-1}} | [http://wiki.stargate-sg1-solutions.com/index.php/3.17_%22A_Hundred_Days%22_Transcript Transcript]] whilst another was still capable of creating a stable wormhole while on a planet near a newly-formed black hole.[{{cite episode| episodelink=A Matter of Time (Stargate SG-1)| title=A Matter of Time| serieslink=Stargate SG-1| series=Stargate SG-1}} | [http://wiki.stargate-sg1-solutions.com/index.php/2.15_%22A_Matter_Of_Time%22_Transcript Transcript]] A Stargate has also been seen to continue functioning whilst entering a sun,[{{cite episode| episodelink=Exodus (Stargate SG-1)| title=Exodus| series=Stargate SG-1| serieslink=Stargate SG-1}} | [http://wiki.stargate-sg1-solutions.com/index.php/4.22_%22Exodus_Part_1%22_Transcript Transcript]] though it was protected by a portable forcefield for a portion of its journey.
In the ninth season of ''Stargate SG-1'' the [[United States]] is revealed to have developed a [[Fictional materials in the Stargate universe#Naqahdriah|naqahdriah]]-enhanced "Gatebuster" [[Nuclear weapon|nuclear bomb]] that was theoretically capable of destroying a Stargate (The Mark IX). However, when it was first used it failed to destroy the intended Stargate. This could have been for several reasons: the Stargate was active, which may have increased its durability; the [[Prior (Stargate)|Prior]] made contact with the Stargate a moment before the explosion, perhaps harnessing an [[Ori (Stargate)|Ori]]-induced power; the shield surrounding the Stargate could have absorbed the blast; or the bomb may have simply not been powerful enough.
However, there ''have'' been incidents when a Stargate was destroyed. [[Anubis (Stargate)|Anubis]] used a piece of Ancient technology to destroy the [[Stargate Command|SGC]]'s Antarctic gate, and used a weapon of his own creation to destroy the gate on Abydos.
=== Exceptions ===
Normally, a wormhole can only be maintained for slightly more than thirty-eight minutes. This time-limit has been exceeded on three occasions: first, when the Earth gate was connected to a gate in proximity to a black hole ("[[A Matter of Time (Stargate SG-1)|A Matter of Time]]"); second, after an energy-producing water maintained the power for a gate while a Russian vehicle had its transmitter stuck ("[[Watergate (Stargate SG-1)|Watergate]]"); third, [[Anubis (Stargate)|Anubis]] used a weapon made by the [[Ancient (Stargate)|Ancients]] (or with their technology) to slowly feed energy to a Stargate, eventually causing it to explode ("[[Redemption (Stargate SG-1)|Redemption]]"). Also, the [[Ori (Stargate)|Ori]] possess the ability to keep a [[Supergate (Stargate)|Supergate]] open indefinitely between galaxies ("[[Beachhead (Stargate SG-1)|Beachhead]]") but this is most likely due to the use of a black hole as a power source.
=== Other uses ===
In several episodes of the series, the Stargate network was used for a purpose other than interplanetary travel. These extra functions of the Stargate are, however, usually discovered by a fluke, and were not intended in the design of the network and individual Stargates. Two such occurrences regard the Stargate's interaction with time, such as "[[1969 (Stargate SG-1)|1969]]", in which the SG-1 team accidentally travels backward in time to the year 1969, as a result of the matter transmission stream passing through a [[solar flare]]. This resulted in a slingshot phenomenon which sent their matter back to Earth, but to a much different time. Carter intentionally uses this phenomenon in the episode "[[2010 (Stargate SG-1)|2010]]", where she uses advanced technology to predict a flare and send a message back in time. Time is also a factor in the episode "[[Window of Opportunity (Stargate SG-1)|Window of Opportunity]]", when a scientist uses a failed time machine built by the Ancients to isolate a region defined by 14 Stargates from the rest of the space-time continuum, causing a [[time loop]].
In several episodes, the Stargate, and the cobbled-together dialing program utilized by the SGC, nearly were the cause of disaster. In the episode "[[Red Sky (Stargate SG-1)|Red Sky]]", the bypassing of a system error caused the Stargate to introduce atoms of a [[Transuranium element|super heavy element]] into the center of a star, causing the star to become unstable. In the episode "[[Ripple Effect (Stargate SG-1)|Ripple Effect]]", the passage of a Stargate matter stream through a black hole caused the creation of a passageway into alternate realities. The Tok'ra use a Stargate's "kawoosh" to disintegrate their dead, a method necessary to them as a covert body. Finally, one Stargate can be caused to dial multiple other gates simultaneously, allowing a blast wave such as that of the [[Dakara Superweapon]] to extend almost indefinitely throughout the galaxy, as is seen in "[[Reckoning (Stargate SG-1)|Reckoning]]".
== Surrounding plot ==
{{spoiler}}
[[Image:Film stargate.jpg|thumb|The Stargate is found, and raised out of the sand.]]
The [[Stargate (film)|''Stargate'']] film begins in 1928, when the titular alien device is first discovered and unearthed at [[Giza]]. It quickly skips to the "present day" (1994), in which an unsuccessful archaeologist [[Daniel Jackson]] is giving a lecture about his outlandish theories that the [[Egyptian pyramids]] were not built by the [[pharaoh]]s. After he is laughed away, an aged [[Catherine Langford]] meets with him, and recruits his [[egyptology|egyptological]] talent, taking him to a top-secret military base at Creek Mountain, where he is instructed to decipher the unique [[Egyptian hieroglyph]]s present on a set of cover-stones. He realises that the indecipherable glyphs are in fact not words but images of [[constellation]]s, such that by identifying 7 of them a position in space can be extrapolated. He is then shown the Stargate itself, uses his new understanding to identify the 7th symbol, and the gate is opened for the first time.
It was thought that only two Stargates existed, connecting Earth and the planet [[Abydos (Stargate)|Abydos]], which was visited in the film. At the beginning of the ''Stargate SG-1'' series, however, a large set of additional valid coordinates were discovered engraved in ruins on Abydos. Because the coordinates pick out stars, and because time leads to [[Big Bang|stellar drift]], other addresses were impossible to dial until [[Samantha Carter]] reworked the dialing system on Earth to account for this movement.
The alien race encountered in the original movie is later developed in ''SG-1'' as the [[Goa'uld]], the dominant evil power in the Milky Way. The leaders of this race, the [[System Lord]]s, pose as Gods and use the Stargates to cart slaves between worlds; this accounts for why many peoples encountered on other planets either fear the Stargate or associate it with the Gods, and also why they are human. For a long time it was thought that the Goa'uld were the builders of the Stargate network, but it was later discovered that they had merely made use of the relics left behind by the Ancients.
For most of ''[[Stargate SG-1]]'', Earth is under constant threat from the Goa'uld, and is no match for their superior technology. The top-secret base is dubbed [[Stargate Command|the SGC]] (Stargate Command), and teams are gathered that will use the Stargate to travel to other planets for the sake of building alliances and procuring technology that could help to defend Earth. The primary team is called [[SG-1]], and the series follows their adventures.
At the climax of ''SG-1'''s 6th season, Daniel Jackson discovers that the Earth myth of [[Atlantis]] is in fact founded upon the Lost City of the Ancients, and Season 7 is spent trying to locate it. At the beginning of the show ''[[Stargate Atlantis]]'', which coincides with the beginning of ''SG-1'''s 8th season, the city is found in the Pegasus Galaxy, and 8 chevrons are dialed to send an expedition there on what could be a one-way trip. It is there that they discover a whole other system of gates, and are plagued by the nemesis of the Ancients, the [[Wraith (Stargate)|Wraith]].
== Milky Way ==
[[Image:Milky Way Stargate (blank).png|thumb|Schematic diagram of a Milky Way stargate]]
A [[Milky Way]] Stargate has thirty-nine inscribed symbols on the inner ring. When dialing, this inner ring rotates until the dialed symbol is aligned with the seventh chevron, at which point the ring pauses, the seventh chevron moves down and up, and the appropriate chevron in the sequence engages. In the ''[[Stargate SG-1]]'' series, an engaged chevron glows red. In the original ''[[Stargate (film)|Stargate]]'' film, all of the chevrons use this motion, and none of them glow red.
With 39 symbols, the Stargate Network in the Milky Way has:
:38×37×36×35×34×33 = 1,987,690,320 possible addresses.
8-symbol addresses will yield:
:38×37×36×35×34×33×32 = 63,606,090,240 possible addresses.
However, not all of them represent valid coordinates (i.e. ones where a Stargate is present). Most sets of destination coordinates do not have a Stargate located at them; there are sufficiently few valid coordinate sets that randomly dialing the Stargate is largely futile.
Because the gate on Earth was found without a DHD, the Stargate team on Earth developed the technology to interface with the gate in order to power it and dial it by the use of computers. In ''[[Stargate SG-1]]'', when dialing the Stargate using a DHD, its inner ring does not spin, it simply just activates each chevron as they are entered on the DHD. Some species in the series (such as the [[Nox (Stargate)|Nox]]) possess the ability to instantanously activate a wormhole, thus being able to dial the gate without using a dialing device.
=== Symbols at Giza ===
The Stargate found at [[Giza]], [[Egypt]] was the first discovered by humans of Earth, and was the one used by the [[Stargate Command|SGC]] for a long time to explore other galaxies. Its symbols are as follows:
{| class="wikitable" border="1" cellspacing="0" cellpadding="2" style="background-color:white;"
|-
!style="background-color:#F5F5F5;"|Position
!style="background-color:#F5F5F5;"|Glyph
!style="background-color:#F5F5F5;"|Constellation
!style="background-color:#F5F5F5;"|Position
!style="background-color:#F5F5F5;"|Glyph
!style="background-color:#F5F5F5;"|Constellation
!style="background-color:#F5F5F5;"|Position
!style="background-color:#F5F5F5;"|Glyph
!style="background-color:#F5F5F5;"|Constellation
|-
|1
|[[Image:StargateGlyph01.png]]
|Origin symbol*
|14
|[[Image:StargateGlyph14.png]]
|[[Microscopium]]
|27
|[[Image:StargateGlyph27.png]]
|[[Taurus (constellation)|Taurus]]
|-
|2
|[[Image:StargateGlyph02.png]]
|[[Crater (constellation)|Crater]]
|15
|[[Image:StargateGlyph15.png]]
|[[Capricornus]]
|28
|[[Image:StargateGlyph28.png]]
|[[Auriga (constellation)|Auriga]]
|-
|3
|[[Image:StargateGlyph03.png]]
|[[Virgo]]
|16
|[[Image:StargateGlyph16.png]]
|[[Piscis Austrinus]]
|29
|[[Image:StargateGlyph29.png]]
|[[Eridanus (constellation)|Eridanus]]
|-
|4
|[[Image:StargateGlyph04.png]]
|[[Boötes]]
|17
|[[Image:StargateGlyph17.png]]
|[[Equuleus]]
|30
|[[Image:StargateGlyph30.png]]
|[[Orion (constellation)|Orion]]
|-
|5
|[[Image:StargateGlyph05.png]]
|[[Centaurus]]
|18
|[[Image:StargateGlyph18.png]]
|[[Aquarius]]
|31
|[[Image:StargateGlyph31.png]]
|[[Canis Minor]]
|-
|6
|[[Image:StargateGlyph06.png]]
|[[Libra]]
|19
|[[Image:StargateGlyph19.png]]
|[[Pegasus (constellation)|Pegasus]]
|32
|[[Image:StargateGlyph32.png]]
|[[Monoceros]]
|-
|7
|[[Image:StargateGlyph07.png]]
|[[Serpens|Serpens Caput]]
|20
|[[Image:StargateGlyph20.png]]
|[[Sculptor (constellation)|Sculptor]]
|33
|[[Image:StargateGlyph33.png]]
|[[Gemini]]
|-
|8
|[[Image:StargateGlyph08.png]]
|[[Norma (constellation)|Norma]]
|21
|[[Image:StargateGlyph21.png]]
|[[Pisces]]
|34
|[[Image:StargateGlyph34.png]]
|[[Hydra (constellation)|Hydra]]
|-
|9
|[[Image:StargateGlyph09.png]]
|[[Scorpius]]
|22
|[[Image:StargateGlyph22.png]]
|[[Andromeda (constellation)|Andromeda]]
|35
|[[Image:StargateGlyph35.png]]
|[[Lynx (constellation)|Lynx]]
|-
|10
|[[Image:StargateGlyph10.png]]
|[[Corona Australis]]
|23
|[[Image:StargateGlyph23.png]]
|[[Triangulum]]
|36
|[[Image:StargateGlyph36.png]]
|[[Cancer (constellation)|Cancer]]
|-
|11
|[[Image:StargateGlyph11.png]]
|[[Scutum]]
|24
|[[Image:StargateGlyph24.png]]
|[[Aries]]
|37
|[[Image:StargateGlyph37.png]]
|[[Sextans]]
|-
|12
|[[Image:StargateGlyph12.png]]
|[[Sagittarius]]
|25
|[[Image:StargateGlyph25.png]]
|[[Perseus (constellation)|Perseus]]
|38
|[[Image:StargateGlyph38.png]]
|[[Leo Minor]]
|-
|13
|[[Image:StargateGlyph13.png]]
|[[Aquila (constellation)|Aquila]]
|26
|[[Image:StargateGlyph26.png]]
|[[Cetus]]
|39
|[[Image:StargateGlyph39.png]]
|[[Leo]]
|}
*This symbol is unique to the Stargate recovered from Giza. In the movie, Dr. Jackson interpreted it as representing the Sun over the peak of a pyramid. Other Stargates have their own unique origin symbols, including the Antarctic Stargate that was also found on Earth.
Note that some of these constellations, such as Microscopium and Sculptor, were not defined until 1763, and, therefore, could not have been included on an artifact of the gate's age.
== Pegasus galaxy ==
[[Image:Pegasus-gate2.jpg|thumb|The Atlantis Stargate]]
In the [[spin-off|spinoff]] series ''[[Stargate Atlantis]]'', an expedition dials the 8-symbol address {{Milky Way Gate Address|39|21|02|16|15|08|{{SGGlyph|Stargate|37|16}}|{{SGGlyph|Stargate|01|16}}|pixelwidth=16|openbracket=|closebracket=}}
from [[Stargate Command]] to travel to the [[Ancient (Stargate)|Ancients]]' [[Atlantis (Stargate)|Lost City of Atlantis]], located in the [[Pegasus Galaxy (Stargate)|Pegasus Galaxy]]. They find that the Ancients seeded planets throughout the Pegasus galaxy with Stargates too, but used gates of a slightly different design. However, the differences are mostly cosmetic.
Pegasus Stargates have teal chevron lights instead of red ones, and the address symbols are groups of small blue lights that appear to "rotate" across the ring instead of embossed figures. Unlike the Milky Way gates, there are 36 Symbols on the gate, but 7 symbols are still required to dial an interplanetary address — which totals 1,168,675,200 possible combinations from each Pegasus galaxy Stargate, fewer than those in the Milky Way but adhering to the same constraints. The address ring does not rotate; instead, the symbols light up sequentially to indicate which one is currently selected. This probably means that manual dialing of Pegasus gates is not possible.
[[Image:Pegasus-gate.jpg|thumb|An orbital Stargate in the Pegasus Galaxy]]
In an apparent departure from the standard "anywhere to anywhere" dialing capabilities of Stargates, the only Stargate in the Pegasus galaxy that's capable of reaching Stargates in the Milky Way is the one located in Atlantis. This is due to a special control crystal apparently unique to the Atlantis DHD without which a Pegasus Stargate cannot encode its eighth chevron. This is likely a deliberate feature, as the Ancients fled the Pegasus galaxy to take refuge in the Milky Way and sealed their fortified city behind them; they did not wish to inflict the [[Wraith (Stargate)|Wraith]] on the Milky Way, for obvious reasons.
Unlike any other known gates, the Atlantis Gate can also identify the point of origin of the gate that tries to dial in, and can block an incoming wormhole. This was used to keep Atlantis sealed for 10,000 years and was programmed in by the Ancients before they fled the city after meeting an alternate Dr. Weir. This Dr. Weir then revealed this to the "second" Atlantis expedition after being revived from an Ancient stasis pod.[{{cite episode| episodelink=Before I Sleep (Stargate Atlantis)| title=Before I Sleep| series=Stargate Atlantis| serieslink=Stargate Atlantis}} | [http://www.moon-catchin.net/gatenoise/sgatranscripts/s1/115beforeisleep.htm Transcript]]
Some Pegasus Stargates are orbital: they lead to open space, something never seen in the Milky Way. These apparently have no DHD, and are used exclusively for [[spacecraft]] travel, specifically that of the [[Puddle jumper (Stargate)|Puddle jumper]] ship-class and the enemy [[Wraith dart]]s. Orbital Stargates are powered by three power nodes spaced equally along the outer ring. These nodes take the place of the standard DHD in powering the Stargate. The Puddle Jumpers have inbuilt DHDs making travel back through these gates possible, and it appears that Wraith Darts have a similar capability, as they were able to open a wormhole remotely during their first encounter with the Atlantis team.[{{cite episode| episodelink=Rising (Stargate Atlantis)| title=Rising| series=Stargate Atlantis| serieslink=Stargate Atlantis}} | [http://wiki.stargate-sg1-solutions.com/index.php/9.08_%22Babylon%22_Transcript Transcript Part I], [http://www.moon-catchin.net/gatenoise/sgatranscripts/s1/102risingpt2.htm Transcript Part II]]
The Atlantis Stargate also features a protective force field which can prevent enemy travellers or weapons from rematerializing, much like the [[Iris (Stargate)|Iris]] installed on Earth's Stargate by the [[Stargate Command|SGC]]. A similar technology appeared in ''Stargate SG-1'', where it was used by [[Anubis (Stargate)|Anubis]] to protect his [[Kull Warrior|super soldier]] production facility; however, this shield could be safely penetrated by wearing a super solider's armor; a similar shield also appeared in the episode "[[Orpheus (Stargate SG-1)|Orpheus]]".
=== Symbols at Atlantis ===
{| class="wikitable" border="1" cellspacing="0" cellpadding="2" style="background-color:white;"
|-
!style="background-color:#F5F5F5;"|Position
!style="background-color:#F5F5F5;"|Glyph
!style="background-color:#F5F5F5;"|Position
!style="background-color:#F5F5F5;"|Glyph
!style="background-color:#F5F5F5;"|Position
!style="background-color:#F5F5F5;"|Glyph
|-
|1
|[[Image:AtlantisGlyph01.png|55px]]
|13
|[[Image:AtlantisGlyph13.png|55px]]
|25
|[[Image:AtlantisGlyph25.png|55px]]
|-
|2
|[[Image:AtlantisGlyph02.png|55px]]
|14
|[[Image:AtlantisGlyph14.png|55px]]
|26
|[[Image:AtlantisGlyph26.png|55px]]
|-
|3
|[[Image:AtlantisGlyph03.png|55px]]
|15
|[[Image:AtlantisGlyph15.png|55px]]
|27
|[[Image:AtlantisGlyph27.png|55px]]
|-
|4
|[[Image:AtlantisGlyph04.png|55px]]
|16
|[[Image:AtlantisGlyph16.png|55px]]
|28
|[[Image:AtlantisGlyph28.png|55px]]
|-
|5
|[[Image:AtlantisGlyph05.png|55px]]
|17
|[[Image:AtlantisGlyph17.png|55px]]
|29
|[[Image:AtlantisGlyph29.png|55px]]
|-
|6
|[[Image:AtlantisGlyph06.png|55px]]
|18
|[[Image:AtlantisGlyph18.png|55px]]
|30
|[[Image:AtlantisGlyph30.png|55px]]
|-
|7
|[[Image:AtlantisGlyph07.png|55px]]
|19*
|[[Image:AtlantisGlyph19.png|55px]]
|31
|[[Image:AtlantisGlyph31.png|55px]]
|-
|8
|[[Image:AtlantisGlyph08.png|55px]]
|20
|[[Image:AtlantisGlyph20.png|55px]]
|32
|[[Image:AtlantisGlyph32.png|55px]]
|-
|9
|[[Image:AtlantisGlyph09.png|55px]]
|21
|[[Image:AtlantisGlyph21.png|55px]]
|33
|[[Image:AtlantisGlyph33.png|55px]]
|-
|10
|[[Image:AtlantisGlyph10.png|55px]]
|22
|[[Image:AtlantisGlyph22.png|55px]]
|34
|[[Image:AtlantisGlyph34.png|55px]]
|-
|11
|[[Image:AtlantisGlyph11.png|55px]]
|23
|[[Image:AtlantisGlyph23.png|55px]]
|35
|[[Image:AtlantisGlyph35.png|55px]]
|-
|12
|[[Image:AtlantisGlyph12.png|55px]]
|24
|[[Image:AtlantisGlyph24.png|55px]]
|36
|[[Image:AtlantisGlyph36.png|55px]]
|}
*This origin symbol is unique to the Stargate in Atlantis. Other Stargates have their own unique origin symbols.
==Ori "Supergates"==
{{main|Supergate (Stargate)}}
[[Image:Supergate.jpg|thumb|An Ori "Supergate".]]
In the ninth season of ''Stargate SG-1'', it was discovered that the Ancients, originally called the Alterans, were not native to the Milky Way, but originated from another galaxy more distant from Earth than the Pegasus galaxy.
While it is not known what the Stargates in the Ori galaxy look like, their presence is implied by the fact that the [[Ori (Stargate)|Ori]] (Alterans who remained behind and did not follow the others of their kind to the Milky Way) were able to send [[Prior (Stargate)|Priors]] (religious messengers) to the Milky Way through a Stargate. Since the transport rings used in the Origin galaxy are white and pearly in appearance, it is fair to assume that the Origin Stargates have a similar appearance. Any gates in the Origin galaxy would far predate both the Pegasus system gates and the Milky Way system gates.
The Ori have demonstrated a far greater knowledge of Stargates and wormhole physics than anyone in the Milky Way with the possible exception of the Ancients. On at least two occasions[{{cite episode| episodelink=Beachhead (Stargate SG-1)| title=Beachhead| series=Stargate SG-1| serieslink=Stargate SG-1}} | [http://wiki.stargate-sg1-solutions.com/index.php/9.06_%22Beachhead%22_Transcript Transcript]][{{cite episode| episodelink=Camelot (Stargate SG-1)| title=Camelot| series=Stargate SG-1| serieslink=Stargate SG-1}}] they attempted to create a massive Stargate, 300 to 400 metres in diameter, which was made of individual modules which formed the ring around what Lt. Col. Carter called a "[[Supergate (Stargate)|Supergate]]". The lack of an inner track on the supergate suggests that it must be remotely dialed. By means of a blackhole this connection is likely to be permanent.
== Making of the props ==
Two full Stargate [[Theatrical properties|prop]]s were originally built for the ''SG-1'' [[television pilot|pilot]] {{sgcite|Children of the Gods|1}}, the second of which was reconstructed from the prop used in the [[Stargate (film)|film]]. They are made of [[steel]] and [[fiberglass]], and are 22 feet in diameter. The second prop is less detailed, and is used for exterior scenes; in the pilot it was used solely on the planet [[Chulak]]. The primary one, however, is quite sophisticated. It is fully automated, and capable of rotating and emitting light. This is achieved by the use of a specially-designed 22-foot circular [[gear]], which turns the inner ring on a precise [[pinion]] drive wheel, using an eight [[horsepower]] electric motor. The top seven chevrons emit [[laser]] pulses which are read by a sensor fed into a computer responsible for the gate's movement, which is consequently able to start and stop the rotation very quickly. This main prop is kept almost immovably at the permanent set of the [[Stargate Command|SGC]], at Bridge Studios, [[Vancouver]].[Production notes for ''Stargate SG-1''; URL:
http://www.rdanderson.com/stargate/productn/productn.htm]
[[Image:Iris prop.jpg|thumb|The Iris prop]]
There are further Stargate props which are no more than two-dimensional or semi-three-dimensional (jar-lid shaped) Stargates, being more lightweight and so easier to erect on location. These are always filmed front-on to preserve the illusion. If a shot involves the [[Iris (Stargate)|Iris]], this is added in post-production, as the mechanics of it opening and closing would be very difficult to build. However, when a Stargate is filmed with just a closed Iris (i.e. without it moving), a tangible prop is inserted into place.
[[Image:Stargate greenscreen.jpg|thumb|left|Stargate prop with rear [[Bluescreen|greenscreen]]]]
The visual effects for ''Stargate SG-1'' and ''Stargate Atlantis'' are predominantly produced by the company ''[[Rainmaker Digital Effects|Rainmaker]]''. The "kawoosh" effect, both in the film and series, on account of being "difficult to achieve"[Stuart Bradley, special effects supervisor, ''SG-1''.], was generated only once and recorded from various angles; this recording is the same used for all kawoosh shots. Rather than being a jet of water, it is actually the image of high-pressure air being blasted ''into'' a tank of water. The effect was achieved by mounting a jet airplane engine two feet above a water tank, and using its 180 mph windstream to create the sufficient water displacement. In post production, the surrounding water was removed with computer editing, and the image of the air-jet pasted into the centre of the opening Stargate.
To cut down on costs, the opening of a Stargate is often just ''implied'' rather than shown, by a costless sound-effect followed by distinct lighting effects characteristic of light being shined through water (as the event horizon is depicted). The [[Stargate SG-1 DVD|DVD]] commentary for ''Stargate SG-1'' explains that these effects are produced by reflecting light off a large sheet of [[aluminium]].
The Stargate itself is nearly always filmed against a [[bluescreen|blue or green]] backdrop, not only making it easier to paste the kawoosh imagery onto the scene, but also facilitating the superimposition of the "event horizon ripple effect", which is entirely [[computer-generated]]. On occasion, the Stargate itself is also completely swapped out for a computer generated model, usually in cases where it is being moved, or is depicted in space. Series producer [[Robert C. Cooper]] explained that it often costs a lot to erect a Stargate on location, and so in some cases offworld gates are also entirely a visual effect[[[GateWorld]] interview, URL: http://www.gateworld.net/articles/interviews/cooper01.shtml].
== Other uses of the concept ==
The basic concept of a Stargate did not originate with the movie ''Stargate''. [[Arthur C. Clarke]] first coined the term "Star Gate" in his novel ''[[2001: A Space Odyssey (novel)|2001: A Space Odyssey]]'' (1968) as a fictional device allowing rapid travel between distant locations. Clarke’s "Star Gate" does not resemble the one described in this article; nevertheless, ''[[Stargate SG-1]]'' paid homage to Clarke in the two episodes "[[2001 (Stargate SG-1)|2001]]" and "[[2010 (Stargate SG-1)|2010]]," which correspond to the first two books in his ''Space Odyssey'' series: ''[[2001: A Space Odyssey (novel)|2001: A Space Odyssey]]'' and ''[[2010: Odyssey Two]]''.
Other writers have since used the name. In the [[personal computer|PC]] [[MMORPG]] ''[[EVE Online]]'', a large object called a Stargate lets you travel between solar systems. [[Stephen Robinett|Stephen Robinett's]] book "''Stargate''" (1976) revolves around the corporate side of building extra-dimensional and/or transportational stargates. In the novel, the Stargate is given the name "Jenson Gate", after the fictional company which builds it.
Authors Lynn Picknett and Clive Prince also write of "''The Stargate Conspiracy: The Truth About Extraterrestrial Life and the Mysteries of Ancient Egypt''". The book details an alternative theory which ingrains the term Stargate with Egypt's past: either the pyramid itself is a gateway to the stars (because of the shafts pointing to a star) or the building of Heaven on Earth based on geographical location of the great and outlying pyramids (cf. [[Orion]]).
=== Common envisioning ===
[[Image:STCityForever.jpg|thumb|right|The ''Enterprise'' crew ([[Star Trek: The Original Series|TOS]]) in front of the Stargate-like [[Guardian of Forever]].]]
There is a widespread conception within science fiction culture of what a "portal" should look like, with a large proportion of such devices bearing resemblances to a Stargate. The "ripple effect" is the most common part of this conception. Examples include the "warp gates" in ''[[Jak 3]]'' which are rings containing a rippling blue substance used for transportation; a portal in ''[[ReBoot]]'', created by the characters Megabyte and Dot displays a rippling "event horizon"; and the "Waygates" in ''[[Warcraft III]]'' which bear a shimmering portal.
The [[Guardian of Forever]], an artefact of the [[Star Trek|Star Trek universe]], bears a strong resemblance. The device could open [[spacetime]] portals to any point in history on any world in the universe, and was ring-shaped with a watery "event horizon". It was first seen in the ''[[Star Trek: The Original Series]]'' episode "[[The City on the Edge of Forever (TOS episode)|The City on the Edge of Forever]]" (1967) and later in the ''[[Star Trek: The Animated Series]]'' episode "[[Yesteryear (TAS episode)|Yesteryear]]" (1974). Again in ''Star Trek'', portals (with angular frames) and ripple effects are seen in the ''[[Star Trek: Deep Space Nine]]'' episode "[[To The Death (DS9 episode)|To The Death]]".
=== Common functions ===
[[Image:X3 Jumpgate.jpg|thumb|A "[[jumpgate]]" of the [[X universe]], part of a space-travel network.]]
The concept of "gates" that can span huge distances are used abundantly in science-fiction to cast protagonists into new territory. In the PC game ''[[Outcast (game)|Outcast]]'' ([[Appeal]]), stargate-like devices called "the Daoka" can be used to travel between the many regions of the game world Adelpha, and in the PC game ''[[Master of Orion]]'' by [[MicroProse]] "Stargates" can be built to orbit individual star systems. The games ''[[Primal]]'' ([[SCEE]]) and ''[[Turok|Turok the Dinosaur Hunter]]'' feature gateways that allow instantaneous travel between locations. Portals of this kind are particularly popular in computer games as they can be used to neatly split a game into [[level]]s.
An early precursor to Stargate-like devices can be seen in the television series ''[[Buck Rogers in the 25th Century (TV series)|Buck Rogers in the 25th Century]]'' (1979-1981), where travel between stars was also accomplished by a Stargate network, similar to [[jumpgate]]s in other series. Each Stargate carries a designation such as "Stargate 4." These stargates however were only shown as a diamond-shaped quartet of stars that shimmered when a vessel was making transit.
Controversially, in the 1982 ''[[Fringeworthy]]'' role-playing game, travellers use a device that very much resembles a Stargate to travel to other dimensions. It was also built by an ancient race long gone. Some members of the gaming industry have claimed that the movie ''Stargate'' directly plagiarized from this game[{{cite web| url=http://forums.guildofgreeters.com/index.php?showtopic=8083&pid=120349&mode=threaded| title= New Movies - Guild of Greeters General Off-Topic forum| month=April 13| year=2005| accessdate=2006-03-09| authors=Robyn}}].
The 1984 cartoon series ''Transformers'' also featured a Stargate-like device called the Space Bridge, which consisted of two rings laying on the ground. When activated, what was inside the ring would be drawn into a subspace tunnel and sent to the other destination. Much like the Stargate, the Space Bridge Earth station featured a spinning ring. Unlike the Stargate, matter was not broken down, but stayed instact inside the subspace tunnel.
Other games involving Stargate-like devices include ''[[Descent: Freespace]]'', in which humans discover gigantic, ship-sized rings (called "Knossos portals") used for faster-than-light travel, created by a race known as "the Ancients"; ''[[Metroid Prime 2: Echoes]]'' ([[Nintendo Gamecube|Gamecube]]), in which a number of ring-shaped dimensional portals allow the main characters to travel between a "Light" and "Dark" version of a planet; and ''[[Homeworld 2]]'' (PC), in which "Hyperspace Gates" serve as the centerpiece of one of the game's final missions; these are massive rings that create wormholes capable of transporting matter great distances.
=== Other similar concepts ===
In a ''[[Star Wars]]'' novel, an ancient system of "Hypergates" were used by an extinct alien species known as the Gree Enclave. These were nowhere near as sophisticated as the "Gates" of the Stargate Universe, and are considered an inferior technology to the abundant "hyper-drives" of the ''Star Wars'' universe.
In [[C. J. Cherryh|C. J. Cherryh's]] ''[[The Morgaine Stories|Morgaine]]'' series (1976), a set of "gates'" potential for facilitating [[time travel]] makes them a danger to [[causality]] and therefore to the future of civilization. The title character is engaged on a centuries-long quest that takes her from world to world via the gates, setting each gate to [[self-destruct]] just after she has used it to move on to the next. Cherryh has cited similar time-gate devices in the works of [[Edgar Rice Burroughs]] and [[Andre Norton]] as influences on the development of her gate system.[{{cite web|url=http://www.cherryh.com/www/list.htm|title=Cherryh.com|work=Author's website}}]
[[Dan Simmons|Dan Simmons']] ''[[Hyperion Cantos|Hyperion]]'' universe (1989) contains devices called "farcasters" which permit instantaneous travel between them via dialed or permanent connections. Farcasters can be either terrestrial in the form of doors or rings, or orbital in the form of rings. These were discovered to be part of a plot by the AI TechnoCore to use human brainpower to assist in the creation of the "Ultimate Intelligence", a sort of machine [[God]]. After this was discovered, the farcaster network was destroyed.
==See also==
*[[List of Technology in the Stargate universe]]
*[[List of Stargate planets]], which lists all known gate addresses
*''[[Stargate SG-1]]''
*''[[Stargate Atlantis]]''
*[[List of Stargate SG-1 episodes|List of ''Stargate SG-1'' episodes]]
*[[List of Stargate Atlantis episodes|List of ''Stargate Atlantis'' episodes]]
==References==
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[[Category:Faster-than-light travel]]
[[Category:Fictional gates]]
[[Category:Stargate technology]]
[[Category:Transportation in fiction]]
[[Category:Wormholes in fiction]]
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