Editing Stargate (device) (section)

== Operation ==
[[Image:Seventh chevron.jpg|thumb|The final [[Chevron (insignia)|chevron]] in the series]]
Within the ''Stargate'' [[fictional universe]], stargates are hyper-advanced large rings that allow interplanetary and intergalactic travel. Objects can travel only from the origin to the destination, while certain electromagnetic waves can travel either way (for instance, visible light does not pass through at all, but radio transmissions pass in both directions).

A stargate's destination is not fixed; any stargate can connect to any other stargate in the network.<ref name=CHILDREN>{{cite episode|title=Children of the Gods|episode-link=Children of the Gods (Stargate SG-1)|series=Stargate SG-1|series-link=Stargate SG-1}}</ref> Stargates have an inner ring akin to a [[rotary dial]] inscribed with a number of symbols, and nine prominent points ("chevrons") spaced equally around their circumference. Between 7 and 9 symbols are combined to identify a destination, by assigning them to each of the chevrons in sequence. These "addresses" are selected by turning the ring until the next symbol in the address is correctly aligned, which associates it with the next chevron. The 8th chevron, if used, specifies a different galaxy; the first 6 chevrons identify points in space within that galaxy to triangulate a physical location;<ref name="film" /> the 7th is a symbol unique to the specific gate, which identifies it as the point of origin; and the 9th is reserved for special destinations.

The gates were originally constructed with complementary control panels nearby, inscribed with the same symbols as can be found on the ring. Pressing these symbols would supply power to the gate and cause the inner ring to spin automatically until the selected symbol is aligned and the chevron engaged. However the gate can also be dialled by manually forcing the ring to move into each position.

Once a valid address is dialed by the traveler, if a functioning counterpart device exists close enough to those coordinates, the stargate generates a stable [[wormhole]] between itself and its counterpart.

The advanced technology of the stargate allows it to accept a wide range of power sources, which it can absorb by direct conduction if required.<ref name=TANTALUS>{{cite episode|title=The Torment of Tantalus|episode-link=The Torment of Tantalus (Stargate SG-1)|series=Stargate SG-1|series-link=Stargate SG-1}}</ref> The power source in most situations is provided by the control panel, which contains a long-lasting power source.

Objects in transit between gates are broken down into their individual [[Chemical element|elemental]] components, and then into energy as they pass through the event horizon, and then travel through a wormhole before being reconstructed on the other side.<ref name="film" /> The journey takes a few seconds, even for the greatest distances. Objects passing between stargates behave as if they pass through a doorway; momentum, for instance, is conserved at either end of the wormhole.

Human travellers exit the stargate with a sense of the journey that has been traversed.<ref name=CHILDREN /> This normally feels effortless, but if the stargate has been improperly operated or is not functioning correctly, can be an uncomfortable experience.<ref name=CHILDREN />

===Addresses===
Each location in the ''Stargate'' universe has its own unique "address", which is a combination of six or more non-repeating symbols appearing on the dialing stargate.{{fact|date=September 2018}}<ref name="Avenger 2.0">{{cite episode|title=Avenger 2.0|episode-link=Avenger 2.0 (Stargate SG-1)|series=Stargate SG-1|series-link=Stargate SG-1|quote=seven symbols chosen from a pool of 38 non-repeating candidates, that's about 63 billion possible combinations.}}</ref> By "dialing" these symbols in the correct order, the traveler selects a three-dimensional destination.

<gallery mode="packed" heights="200px">
Image:Milky Way stargate.png|Schematic diagram of a Milky Way stargate with glyphs
Image:Pegasus stargate.png|Schematic diagram of a Pegasus stargate with glyphs
Image:Destiny stargate.png|Schematic diagram of Destiny's stargate with glyphs
</gallery>

[[Image:Stargatesg1diallingcomputer.jpg|thumb|right|The [[Stargate Command|SGC]]'s Dialing Computer compiling the address of the planet Abydos]]
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]]: <span style="white-space: nowrap;">[[Image:Stargate SG·1 symbol 27.svg|16px]] [[Image:Stargate SG·1 symbol 07.svg|16px]] [[Image:Stargate SG·1 symbol 15.svg|16px]] [[Image:Stargate SG·1 symbol 32.svg|16px]] [[Image:Stargate SG·1 symbol 12.svg|16px]] [[Image:Stargate SG·1 symbol 30.svg|16px]]</span> (corresponding to the constellations of [[Taurus (constellation)|Taurus]], [[Serpens Caput]], [[Capricornus]], [[Monoceros (constellation)|Monoceros]], [[Sagittarius (constellation)|Sagittarius]] and [[Orion (constellation)|Orion]]). As explained by Dr. Daniel Jackson in the movie, the Stargate requires seven correct symbols to connect to another Stargate. As shown in the picture opposite, the first six symbols act as coordinates, creating three intersecting lines, the destination. The Stargate uses the seventh symbol as the point of origin allowing one to plot a straight line course to the destination. With the stargates of the Milky Way, with 38 address symbols and one point of origin, there are 1,987,690,320 possible six symbol co-ordinates (leading to 38!/(38-6)!/8/6=41,410,215 addresses as the six symbol addresses are composed of three tuples that can be permuted in 6 ways and the two symbols within each tuple are invariant for 8 more permutations.). With the stargates of the Pegasus or Destiny, with 35 address symbols and one point of origin, there are only 1,168,675,200 possible six symbol coordinates.

[[Image:StargateCoordinates.svg|thumb|right|This diagram illustrates how Stargate symbols translate to physical coordinates.]]
By identifying six constellations in space, a single [[triangulation|sextangulation]] point can be interpolated that corresponds to the destination desired.<ref name="film">''[[Stargate (film)|Stargate]]'' (1999)</ref> As only a small portion of the possible combinations of Stargate symbols represent valid addresses, dialing the Gate at random is largely futile. In "[[Children of the Gods (Stargate SG-1)|Children of the Gods]]", SG-1 discovers a room on Abydos with a list of valid Stargate addresses and (luckily) a map that allows the SGC to compensate for thousands of years of [[stellar drift]]. In the series, the fictional planet Abydos could be dialed because it is relatively close to Earth, although in the film, Abydos was located in the fictional Kaliam Galaxy.<ref name="film" /> It was initially believed that the Goa'uld created the Stargates, but this was proven false in "The Torment of Tantalus" when the SGC discovered that Earth had accidentally dialled an address in 1945 that was not on the Abydos cartouche. Following this revelation, a larger list of Stargate addresses is provided by [[Jack O'Neill (Stargate)|Jack O'Neill]] in "[[The Fifth Race (Stargate SG-1)|The Fifth Race]]" from knowledge downloaded into his mind by a repository of the Ancients, allowing them to travel to worlds unknown to the Goa'uld.<ref name="The Fifth Race">{{cite episode|title=The Fifth Race|episode-link=The Fifth Race|series=Stargate SG-1|series-link=Stargate SG-1}}</ref> In "[[Rising (Stargate Atlantis)|Rising]]", a list of Stargate addresses in the Pegasus galaxy is found in the [[Atlantis (Stargate)|Atlantis]] database.<ref name=Rising>{{cite episode|title=Rising|episode-link=Rising (Stargate Atlantis)|series=Stargate Atlantis|series-link=Stargate Atlantis}}</ref> The SGC assigns designations to Stargate-accessible planets in the form P''xx-xxx'' or M''xx-xxx''. [[Samantha Carter]] explains in "[[The Broca Divide (Stargate SG-1)|The Broca Divide]]" that the designation "is based on a binary code the computer uses for extrapolation".

Eight-symbol addresses are introduced in "[[The Fifth Race (Stargate SG-1)|The Fifth Race]]", opening up new plot lines by connecting Stargates to different galaxies. The additional symbol acts as a type of "area code". Such connections, in comparison to seven symbol codes, require substantially more energy to complete a functional wormhole – much more than any standard dialing method can provide. In the first instance, opening an intergalactic wormhole is shown to exceed the total power generation capacity of the SGC at the time. O'Neill fashioned an additional power source using spare parts and the liquid naquadah power core of a staff weapon using the same enhanced knowledge that had allowed him to determine this address in the first place,<ref name="The Fifth Race" /> but this new power source only functioned twice and required repair work to operate the second time.<ref name="Point of View">{{cite episode|title=Point of View|episode-link=Point of View (Stargate SG-1)|series=Stargate SG-1|series-link=Stargate SG-1}}</ref> A fully charged [[Vacuum energy|Zero Point Module]] (ZPM) can provide enough power for regular travel between galaxies.<ref name="Rising"/><ref name="Letters from Pegasus">{{cite episode|title=Letters from Pegasus|episode-link=Letters from Pegasus (Stargate Atlantis)|series=Stargate Atlantis|series-link=Stargate Atlantis}}</ref><ref name="Camelot">{{cite episode|title=Camelot|episode-link=Camelot (Stargate SG-1)|series=Stargate SG-1|series-link=Stargate SG-1}}</ref> The 8th chevron is a key element in the [[Stargate Atlantis]] series, allowing travel to the [[Pegasus Galaxy (Stargate)|Pegasus Galaxy]]. For the stargates of the Milky Way, with 38 address symbols and one point of origin, there are 63,606,090,240 possible seven symbol coordinates. The stargates of the Pegasus or Destiny, with 35 address symbols and one point of origin, provide only 33,891,580,800 possible seven symbol coordinates.

''[[Stargate Universe]]'' introduces the concept of a nine-symbol address, the purpose of the ninth chevron never having been explored in the previous series.<ref>{{cite web|url=https://gateworld.net/news/2007/03/universe-deals-with-ninth-chevron/|title=Universe deals with ninth chevron|date=March 25, 2007|publisher=[[GateWorld]]|access-date=March 25, 2007}}</ref> The nine-symbol addresses act as codes to dial specific Stargates, with the only two known nine-symbol addresses used to dial from the [[Milky Way]] galaxy to ''Destiny'', a massive Ancient vessel that was part of a project to explore the universe, with the project being abandoned when they started researching into ascension among other things, and from ''Destiny'' to [[Earth]]. It is unknown if any other Stargates are reachable with a nine-symbol address, or if this is a feature unique to the Stargates on Destiny and Earth. Like eight-symbol addresses, the dialing of this address requires a significant amount of power, such that the scientists on Icarus Base had to tap into the planet's naqahdriah core. With the Stargates of the Milky Way, with 38 address symbols, there are 1,971,788,797,440 possible eight-symbol destinations. With the Stargates of the Pegasus or Destiny, with 35 address symbols, there are only 948,964,262,400 possible eight symbol destinations. Provided the ninth symbol is your point of origin. If the ninth symbol can also be added to the destination, even 59,153,663,923,200 combinations with a Milky Way stargate or 25,622,035,084,800 combinations with a Pegasus or Destiny Stargate are possible.

===Dial-Home Device===
[[Image:Dial-Home Device.jpg|thumb|The Dial-Home Device]]

There are a handful of methods used in the shows to dial a Stargate, and the most common is with the use of a Dial-Home Device. Almost always referred to as the "DHD" for short, it 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 (Milky Way) or blue (Pegasus) hemisphere in the center; the keys represent the symbols on the rim of the Stargate. By pressing these keys a traveler builds an address. The central hemisphere serves as an "[[Carriage return|Enter]]" key to activate the Stargate once a destination has been dialed. Each DHD only has 38 keys, 19 on each ring. According to [[Radek Zelenka|Dr. Zelenka]], dialing an address leaves a small imprint on the control crystals of the DHD, and about fifty addresses can be recovered from a DHD using the proper equipment. However, this gives no indication of the order in which the addresses were dialed, and no guarantee can be made as to the accuracy of the recovered addresses.<ref name="The Lost Boys">{{cite episode|title=The Lost Boys|episode-link=The Lost Boys (Stargate Atlantis)|series=Stargate Atlantis|series-link=Stargate Atlantis}}</ref>

[[Image:Dhdjumper.jpg|thumb|Pegasus/Atlantis puddle jumper DHD console]]
The [[Atlantis (Stargate)|Atlantis]] DHD is more similar to the Earth's dialing computer than an actual DHD, and looks more like a set of crystal panels. It can block out certain gate addresses.<ref name="Before I Sleep">{{cite episode|title = Before I Sleep| episode-link = Before I Sleep (Stargate Atlantis)| series = Stargate Atlantis| series-link = Stargate Atlantis}}</ref> The Atlantis DHD also has an extra control-crystal allowing the dialing of an eighth chevron during the dialing sequence and is the only DHD in the Pegasus Galaxy capable of dialing Earth.<ref name="Home">{{cite episode |title=Home |episode-link=Home (Stargate Atlantis) |series=Stargate Atlantis |series-link=Stargate Atlantis}}</ref> A similar DHD is also used on Puddle Jumpers, where the set of used glyphs corresponds to the galaxy of the Puddle Jumper. The [[Wraith (Stargate)|Wraith]] also travel through Stargates in small spacecraft called darts and have some means of remote-dialing them in a manner similar to Ancient ships.<ref name="The Lost Boys"/>

The show makes it clear that every Stargate originally had its own DHD, located directly in front of the gate and facing it.{{r|TANTALUS}} Over time, however, some DHDs have been damaged or lost. This has been the source of plot difficulties for the protagonists on several occasions, as it is still possible to travel to a Stargate that lacks a DHD, meaning that dialing home again will be much more difficult, if not impossible. One of the primary functions of the Mobile Analytic Laboratory Probe (M.A.L.P.), an [[unmanned ground vehicle]] that precedes an [[SG team]], is to confirm the presence of a DHD.{{r|TANTALUS}} In the absence of a DHD, a user must select the address by manually rotating the inner ring of the Stargate, and use an external power source, as the ring will not rotate unless it is energised.{{r|TANTALUS}} Pegasus Galaxy Stargates do not have a movable ring, so manually dialing these is impossible. Travelers can also emulate a DHD through a dialing computer as present at [[Stargate Command]]. Remote dialers have been used by several races like the [[Goa'uld]] and [[Asgard (Stargate)|Asgard]] in various episodes. As the Stargates in Stargate Universe are a different (less advanced model) the crew of the Destiny are forced to use such a device as no planet visited so far has any variation of DHD present.

===Wormhole===
[[Image:Kawoosh side.jpg|thumb|right|Side-on view of a stargate as an unstable vortex is ejected]]
Once an address is dialed, the gate is said to have created a "stable [[wormhole]]" between itself and the gate dialed. The creation process is depicted with great consistency, and hence has become one of the defining [[Motif (art)|motif]]s of ''Stargate'', at times being central in both the ''SG-1'' and ''Atlantis'' title sequences. It involves the generation of the "puddle of water" portal that lasts roughly two seconds, and is completed by the ejection of an unstable energy vortex resembling a surge of water or [[mercury (element)|quicksilver]]. The vortex is portrayed as a symbol of the stargate's power, invariably causing characters to become affected by [[awe]].<ref name="The Scourge">{{cite episode|title=The Scourge|episode-link=The Scourge (Stargate SG-1)|series=Stargate SG-1|series-link=Stargate SG-1}}</ref> Any matter that comes into contact with the vortex is annihilated on a molecular level, as is dramatically demonstrated by a pair of smoking shoes in the episode "[[Prisoners (Stargate SG-1)|Prisoners]]".<ref name="Prisoners">{{cite episode|title=Prisoners|episode-link=Prisoners (Stargate SG-1)|series=Stargate SG-1|series-link=Stargate SG-1}}</ref> In season 9's "[[Crusade (Stargate SG-1)|Crusade]]", the unstable vortex was [[Onomatopoeia|onomatopoeidiacally]] referred to by Col. Carter as the "Kawoosh", emulating the sound of the initial vortex. This aspect has been used in some cases to dispose of highly hazardous materials. The vortex is also used on one occasion to dispose of a body in a formal funeral service – the body was placed on a pyre in front of the gate, which was then activated.

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, which represents the "event horizon" in the show. In non-fictional parlance, an [[event horizon]] is the perimeter around a [[black hole]] or wormhole beyond which the gravitational pull of the singularity would be too strong to overcome. The wavering undulations characteristic of water are supposed to represent the "fluctuations in the event horizon".<ref name="Children of the Gods">{{cite episode|title=Children of the Gods|episode-link=Children of the Gods|series=Stargate SG-1|series-link=Stargate SG-1}}</ref> This puddle may then be entered (usually accompanied by a watery squishing sound), and the traveler will emerge from a similar pool at the destination Stargate.

The show makes it clear that transit is strictly one-way; an attempt to travel "backwards" causes the traveler to be destroyed.<ref name="A Hundred Days">{{cite episode|title=A Hundred Days|episode-link=A Hundred Days (Stargate SG-1)|series=Stargate SG-1|series-link=Stargate SG-1}}</ref> Although in the first episode the Goa'uld who come through at the beginning appear to walk back through the event horizon after taking a hostage, in actuality they dialed out again using a hand-held device, as the whooshing sound is audible in the background.<ref name="Children of the Gods" /> As matter is only transmitted through a Stargate once the whole object has passed the event horizon, a person or object could be retrieved from the event horizon before entering completely, as the Stargate would automatically reintegrate the traveler.

[[Image:Wormhole Travel Stargate Movie.jpg|thumb|Original wormhole travel from the [[Stargate (film)|''Stargate'']] movie and ''[[SG-1]]'' seasons 1-8]]
Passage through a Stargate's wormhole is depicted as a visual effect of shooting through a tunnel in space. The average travel time between Stargates is 3.2 seconds.<ref name="Insiders">{{cite episode|title=Insiders|episode-link=Insiders (Stargate SG-1)|series=Stargate SG-1|series-link=Stargate SG-1}}</ref> In the movie and early ''SG-1'' episodes, travelers exit from the Stargate covered in frost and at high speed (often being knocked from their feet), feeling as though they have been on a "roller coaster ride". The character Major [[Charles Kawalsky]] describes Stargate travel as worse than "pulling out of a simulated bombing run in an [[F-16 Fighting Falcon|F-16]] at [[g-force|eight-plus ''g'']]", with Major [[Louis Ferretti]] adding that on the other side one is "frozen stiff like having just been through a blizzard naked".<ref name="Children of the Gods" /> In later episodes the experience is no different from stepping through a door,<ref name="Shades of Grey">{{cite episode|title=Shades of Grey|episode-link=Shades of Grey (Stargate SG-1)|series=Stargate SG-1|series-link=Stargate SG-1}}</ref> explained as a result of refinements made to the dialing computer at the [[Stargate Command|SGC]].

Under normal circumstances, a wormhole can only be maintained for slightly more than 38 minutes.<ref name="Thirty-Eight Minutes">{{cite episode|title=Thirty-Eight Minutes|episode-link=Thirty-Eight Minutes (Stargate Atlantis)|series=Stargate Atlantis|series-link=Stargate Atlantis}}</ref> Extending the wormhole duration beyond that requires tremendous amounts of power, such as that provided by a nearby [[black hole]].<ref name=AMatterofTime>{{Cite episode|title=A Matter of Time|episode-link=Stargate SG-1 season 2|series=Stargate SG-1|series-link=Stargate SG-1|airdate=1999-01-29|season=2}}</ref><ref name="First Strike">{{cite episode|title=First Strike|episode-link=First Strike (Stargate Atlantis)|series=Stargate Atlantis|series-link=Stargate Atlantis}}</ref>

While the "kawoosh" effect in the movie was created by filming the actual swirl of water in a glass tube, and looked like a vortex on the back of the Gate,<ref>DVD commentary for the ''Stargate'' film</ref> on the TV series, this effect was completely created in [[Computer graphics|CG]] by the Canadian [[visual effects]] company [[Rainmaker Digital Effects|Rainmaker]]''.''<ref>''Stargate Magic: Inside The Lab.'' Special feature on [[Stargate SG-1 DVD]] Volume 37 (Lost City).</ref> At the beginning of Season 9, the original movie wormhole sequence was substituted by a new sequence similar to the one already used on ''Stargate Atlantis'' but tinted bright blue (whereas in ''Atlantis'' it is green).<ref>Audio commentary for "The Ties That Bind", SG-1.</ref> ''Stargate Universe'' uses a darker shade of blue.

Throughout the run of the television franchise, it cost $5,000 to show a person stepping through the event horizon, using visual effects.<ref>Audio commentary for ''[[Stargate: Continuum]]''</ref>