Stargate

"That is how we're supposed to travel light years across the galaxy to other planets."

- Cameron Mitchell

The Stargates, also called the Astria Porta in Ancient and the Chappa'ai in Goa'uld, are a series of devices, built by the Ancients, that can create artificial Wormholes between distant worlds. The Stargates are often considered to be the Ancients' greatest creation, and so the Ancients are often called the Gate Builders. The Ancients, the Nox, the Asurans, the Tollan (with the assistance of the Nox), and the Ori are the only known races that have managed to build Stargates.

The original Stargate design was invented by an Alteran named Amelius, from an idea he formulated the night before the Alterans left their home galaxy for the Milky Way. It is unknown if he actually built the first of the Stargate Network. They are among the oldest examples of Ancient technology found in the Milky Way galaxy, the Stargate found in Antarctica on Earth has been estimated to be over 50 million years old.

Names
"If that's what you want to call, Ring of the Gods is good."

- Jack O'Neill

The Ancients placed Stargates on thousands of worlds across several galaxies, but the gate network was open to use by all, and continues to be a convenient form of travel for many races. Some races, such as the Goa'uld, grew their ways of life around the gates, which became integral to the functioning of their culture.

In turn, most races developed their own names for the Stargates. The Ancients called them "Astria Porta". The English word "Stargate" is a calque of the Goa'uld word "Chappa'ai", courtesy of a direct translation by Daniel Jackson, and "Chappa'ai" is itself a calque of "Astria Porta". The Wraith call the Stargate the Portal.

Although Stargates are present on many planets, most of the races which inhabit them are relatively primitive, and view the gates as no more than divine, sacred or terrifying relics, as evidenced by such names as "Ring of the Gods" and "Circle of Darkness". The K'Tau call their Stargate "the annulus". In the Pegasus galaxy, villagers know them as Rings of the Ancestors and variations thereof. They are also commonly referred to as as simply "the ring" or "the gate".

Technical specifications
"Kind of a ring thing, comes with a dialler, you hit the symbols, it spins around and lights come on, it kind of flushes sideways..."

- Jack O'Neill

The Stargate is essentially an enormous superconductor, capable of harnessing power from a wide variety of energy sources, especially electricity. When entering through the event horizon, the matter passing through is converted to energy, and then rematerialized at the event horizon of a Stargate. Wormholes are one way only, though it is unknown what happens if someone goes through an incoming wormhole (It is equally unknown what would happen if someone entered the Stargate via the 'back' rather than the 'front'. However, Teal'c once stated that he knew someone who attempted that on one occasion and that his death was "most unpleasant", but further details are unknown. The inner track is a safety feature. When the gate has absorbed enough energy this track will unlock, allowing a manual dial in case something has happened to the D.H.D.

The Stargate has symbols (39 for the Milky Way, 36 for the Pegasus galaxy and others visited by Destiny) which are combined to form a seven-symbol address. Six of the symbols, representing constellations, indicate the destination's three-dimensional coordinates in space, while the seventh indicates the point of origin. For Stargates accessing a destination outside of its galaxy, a seventh constellation symbol is necessary, bringing the total to eight. There are 9 chevrons around the device, allowing up to 9 symbols to be dialled. The ninth chevron was revealed to connect to a specific Stargate aboard the Destiny, as opposed to the normal method of connecting to a specific area and the gate inside it. The Stargates on a planet link it to the so called Stargate network. How far it spans is unknown, but it is known to link the Alteran Home Galaxy, the Milky Way, Pegasus, and the Ida galaxy, and most likely many others through the use of Ancient Stargate seeding ships.

Generally, Stargates have dialling devices (DHDs, an acronym for Dial Home Device) placed in front of them, which can be used similarly to a telephone dial to select the place where the connection should go. The Stargate found on Earth in Egypt was missing its dialling device. It was later discovered that Russia was in possession of the missing DHD. The Russians acquired the DHD during the Second World War, when they invaded Germany.

Opening the Stargate requires an amount of energy much larger than what is required to keep the wormhole open, resulting in an unstable vortex emerging at the "front" of the device. This energy blast will disintegrate anything in its way; however, the vortex can only form if there is a large enough space (several microns) in front of the event horizon. Devices like the iris prevent the vortex from forming. . The vortex creates a pressure wave that is able to move small objects such as hanging lamps. This can be seen at the Kelownan Stargate just before the Tau'ri arrive at Kelowna.

Stargates stay open for a limited period of time; a DHD will force a wormhole to close once the object has reached the other side of the wormhole and no new object has entered, but they are supposed to "time out" at about 38 minutes because a DHD cannot provide enough power to sustain one for longer. There have been rare circumstances where a wormhole has remained active longer, but it requires immense power such as a ZPM or black hole. If there is enough power the gate will automatically remain open if something is still passing through the event horizon. Because it is composed of Naquadah, the Stargate is incredibly durable; some have survived ship impacts, black holes, and even meteor impacts.

In the Pegasus Galaxy, some Stargates have been placed in space in orbit above planets, rather than on their surfaces. Because there is no connected DHD, "Spacegates" are powered by three power nodes that also serve as stabilizers, and dialling is accessed by a panel on a spaceship. Puddle jumpers and Wraith Darts are both equipped with such DHDs, and are among the few ships capable of going through the Stargate. In the Milky Way galaxy, the Goa'uld once used a special glider to fit through the Stargate, but this tactic was abandoned a century ago.

The Ori are known to use the Stargates, as this was the way they originally sent Priors from their galaxy to the Milky Way. This means that they are compatible with the Milky Way Stargates, but all other details about them at this point are unknown.

The eighth chevron's purpose was originally unknown until Colonel Jack O'Neill had the information capabilities of the Ancient's stored within his mind through their Repository of knowledge. Using the Power Booster Device he created, along with modifications he made to the SGC's dialling computer, the Eighth Chevron's purpose was revealed. It added an extra distance calculation to the gate allowing it to travel to other galaxies. Since the Stargate possesses 39 glyphs, the gate network can theoretically access 38 galaxies (disregarding the origin symbol).

The ninth chevron's purpose was also unknown until a reference to it was found in the Ancient database. It works as a code to identify and dial specific Stargates. The only one known address so far is to the gate on Destiny. Dialling it required an enormous amount of power that was supplied through a mechanism which used energy from the core of a planet. The point of origin was Earth even though the aforementioned mechanism wasn't located there. The power core was destabilized when the Lucian Alliance attacked resulting in the destruction of the planet.

Destiny's Gate
"Rush figures that this gate predates all the others we know of, like a prototype."

- Eli Wallace

The Stargate on the Destiny, and those constructed by Stargate seeding ships, are of yet another design of Stargate. These Stargates are suspected to be the first, "prototype" version of the gates—more specifically the gate aboard Destiny, which all others are based on. It was unknown how to activate the ninth chevron of the Stargate until Eli Wallace discovered that it requires a code instead of a coordinate to locate and dial the specific gate aboard Destiny. When activating the eighth chevron, it requires a lot of power to dial, usually supplied by a Zero Point Module. The power requirements for the ninth chevron are even greater; the SGC tapped the naquadriah core of an Icarus-type planet for this purpose.

In the Destiny Gate design, the individual glyphs are separated as opposed to the designs for Pegasus and the Milky Way where they are on an inner ring. They appear not to represent any constellations like Pegasus and Milky Way gates do. The chevrons also appear to be of a slightly different design to what has appeared previously. The triangular part of the chevrons appear to be smaller and more angular at the ends, and the three lines on either side of the triangle are more distinct as individual lights. When dialled, the entire gate spins, unlike the Milky Way Stargate where only the center ring spins. The gate rotates clockwise until the first address glyph is directly below an orb-shaped bearing indicator which hangs above the gate and functions like the chevrons on other gates: it lights up briefly as each symbol locks directly under it. After the previous glyph is locked, the gate changes direction, spinning counter-clockwise until the next glyph is locked. This alternating process continues until the point-of-origin (7th, 8th or 9th) glyph locks, at which point the Gate bearing remains lit and a final chevron in the floor lights as well. As the gate disengages, all lights turn off at the same time. On the Destiny, this is followed by a short blast of CO2 from vents either side of the gate.

Planetary Destiny-style Stargates have no gate bearing. The symbols merely lock where the bearing would be. Planetary gates also emit no CO2 upon disconnection. Planetary gates otherwise work in much the same way. They are semi-embedded in tan-coloured platforms, which allows the gate to freely spin inside it but remain safely secured in place. Upon a Stargate's activation and during its active period, twin strips of yellow-orange lights illuminate each side of the platform to serve as a path to the event horizon.

Matter transmission
"We're going to be demolecularized, transmitted over two thousand light years through subspace, and then, uh, rematerialized on the other side."

- Samantha Carter

When an object passes through the event horizon, it is not immediately transferred to the destination Stargate, but rather the portion that has passed through is dematerialized and held in a "hyperspatial buffer". An object that has not completely passed through the event horizon may be pulled out again, and its atoms will be rematerialized 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. Objects in the buffer remain in a state of suspension. This has been used to "store" people in medical need, but this is a dangerous manoeuvre, since any disintegrated matter in the buffer "ceases to exist" if the wormhole shuts down before the signal is transmitted. Furthermore, each time the gate is activated the buffer is wiped clean to receive new information. If the control crystal of a connected DHD is removed then an event horizon will form without establishing a wormhole, allowing any memory stored in the Stargate to be reintegrated.

Several facets of the Stargate are necessary for it to function as a useful personnel transporter. Matter emerging from a Stargate retains any kinetic energy it had while entering, so a person running into one Stargate will hit the ground running upon emerging from another. (Weapon projectiles also maintain their trajectory and momentum upon transit: a bullet fired through a Stargate is just as dangerous as it would be otherwise.) Also, the transmitting Stargate does not allow the air molecules of the local atmosphere to pass through: the Stargate differentiates between objects attempting to pass through the event horizon and things that would naturally exert pressure, such as water, air, lava, etc. In one case, the constant pressure of water from a broken ice dam applying pressure to the event horizon and to Atlantis's iris shield kept the wormhole active for the maximum amount of time.

Interestingly, it has been found that a Pegasus galaxy Stargate will 'override' a Milky Way gate due to their more advanced design. This was first seen aboard the Midway Space Station and required a special macro to be written allowing both gates to be dialled. A second instance when this effect has been observed was when the Wraith known as 'Kenny' brought a Pegasus gate aboard his ZPM-Powered Hive Ship which overrode the native Earth gate and prevented the Tau'ri from escaping to the Alpha Site. Furthermore, to dial this gate, Dr. Rodney McKay was required to modify the Pegasus DHD to allow it to dial Milky Way co-ordinates, though it was a simple job and took only minutes.

Gate obstruction
"We have in place an impenetrable shield called an Iris."

- George S. Hammond

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- or permanently sealed by burying them.

Another means of controlling travel through a Stargate is by placing a barrier a minuscule distance (less than three micrometers) from the event horizon, which allows the wormhole to form but prevents the reconstitution of matter upon arrival through the gate. In other words, a connection can be made but any matter trying to exit the gate will not regain its original structure, and hence will be annihilated. The iris on the Earth Stargate and the shield on the Atlantis Stargate perform this function, and have been seen to be used as an effective defensive precaution, while still allowing radio communication through the open wormhole. The Goa'uld have also been seen to utilize shields to create much the same effect.

Iris-type barriers also suppress the formation of an unstable vortex by not allowing the matter to form. Such barriers, however, are not the only way to prevent the vortex. Several races, including the Asgard and the Nox, have demonstrated the ability to open a wormhole without the vortex forming, presumably through a more efficient form of energy transmission.

Power source
"The Stargate just got a huge power boost. It's drawing ten times more power than normal."

- Samantha Carter

Power is always required to establish an outgoing wormhole, and is usually supplied by the DHD, but any Stargate can receive a wormhole whether it has a power supply or not; the dialling gate is the one that supplies power to both. In a few cases, Stargates have been dialled "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. Power can be fed directly into the Naqahdah that comprises the gate; power harnessed from lightning strikes 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". Under some conditions, a gate only needs enough power to connect briefly, then the receiving gate can provide enough power to maintain the connection. The same is true if the outgoing gate loses power while transmitting; if the incoming gate has a DHD, it will take over powering the gate until reintegration is complete.

Secondary Stargates
Some planets are known to possess "secondary" or "backup" Stargates. The second Stargate is normally inactive, with the primary Stargate (defined by the presence of a functioning Dial-Home Device) receiving all incoming wormholes. If a Stargate experiences a power surge while an outgoing wormhole is open, the other end of the wormhole has been observed to "jump" to the next closest gate in the network. The effect can also be used as a defensive measure or to close a connection with the receiving Stargate. In the case of a planet with two gates, the closest is the inactive secondary gate. This scenario resulted in the discovery of the Beta Gate in Antarctica by SG-1.

The Antarctic gate was later revealed to have originally been the primary Stargate on Earth, built by the Ancients. The Alpha Gate, found in Giza and originally used in the SGC, was brought to Earth, by Ra, from another planet. Since Stargate addresses correspond to planetary locations and not individual gates, the new gate inherited the same address as the one in Antarctica. Because the Antarctic gate had been abandoned millennia earlier by the Ancients and the DHD had become inactive and disconnected, Ra's gate became the primary as it had a DHD with it.

It has been revealed that the Stargates of the Pegasus galaxy superseded the older, more outdated Stargates, such as the one on Earth. Earth was unable to dial out from the SGC when the Wraith "Super-hive" ship was in orbit with it's own Pegasus Stargate; the programming of the newer gates force it to take precedence over incoming wormholes to the older outdated Stargates, and thus, disabled the Earth gate at the SGC from dialling out. A similar situation was encountered at the Midway Station with the Milky Way and the Pegasus gates.

Durability and Susceptibility
"It could be as much as 50 million years old."

- Samantha Carter

Stargates are very durable; the oldest in the universe is probably the Beta Gate from Antarctica, 50 million years old; though the power source may be younger. The Stargates themselves are extremely resistant to damage or destruction: in one case, a Stargate survived a direct hit from a meteor, while another was still capable of creating a stable wormhole while on a planet near a newly-formed black hole. A Stargate has also been seen to continue functioning whilst entering a sun, though it was protected by a portable force field for a portion of its journey. Even a Naquadah bomb sent by the SGC that destroyed an entire planet left its Stargate intact.

Eventually, the United States developed a Naquadria-enhanced 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, as an Ori shield defending the gate was being powered by the weapon attacks attempting to destroy it. A later attempt against a Pegasus Galaxy Stargate, however, succeeded by placing the bomb behind the gate, so that the energy would not be absorbed by the open wormhole.

Stargates are highly susceptible to subspace interference caused by the Attero Device. The overload in the gate causes an explosion that can be seen from space, several minutes after a connection is established. Two Stargates that were known to have been destroyed from this overload are the Atlantis Stargate and a Stargate on the Traveler settlement.

Exceptions
"There is one exception to that rule. We’ve discovered that if you pump enough energy into it, a Stargate can remain active indefinitely."

- Rodney Mckay

Under normal circumstances, a wormhole can only be maintained for slightly more than 38 minutes. However, on a few occasions, this limit has been surpassed, each time through the supply of a truly massive amount of energy, even by the standards normally reserved for the operation of the Stargate. The first breach of this general rule occurred to Earth's gate connected to a planet in the proximity of a black hole. This method was also used intentionally by the Ori. The second incident occurred when energy-rich liquid beings maintained the power for a gate while a Russian vehicle had its transmitter stuck.

Another exception happened when Anubis used a Stargate destroyer to slowly feed energy to the Beta Gate at the SGC. The gate remained active and eventually exploded. Finally the fourth exception happened after Earth ordered an attack on the Asuran home planet, after it was discovered that they were building warships. The Asurans responded by sending a satellite containing a Stargate to Lantea, which activated and a powerful beam came through hitting Atlantis' shield. The expedition had hoped that the Stargate would shut down after 38 minutes, but, as Dr. McKay stated, the Asurans had a sufficiently large number of ZPMs to power their Stargate indefinitely.

Other uses
"I was asked to research alternative applications for the Gate, including time travel."

- Samantha Carter

Several times, the Stargate network was used for a purpose other than interplanetary travel, although these extra features were almost always discovered by accident, and were not intended in the design of the Stargates. Two such occurrences regard the Stargate's interaction with time, first discovered by SG-1 when they accidentally traveled backward in time to the year 1969, as a result of the matter transmission stream passing through a solar flare. In the year 2010 in an alternate time-line, Samantha Carter intentionally used this phenomenon to send a message back in time. There was also a time when a scientist created a time loop, using a failed time machine built by the Ancients to isolate a region defined by 14 Stargates from the rest of the space-time continuum.

A Stargate can also be used as a weapon capable of destroying an entire solar system. Samantha Carter used this effect when she dialled into a planet in close proximity to a black hole. The gate, protected by a force field, was then catapulted into a sun. The resulting loss of mass caused the sun to go supernova, destroying the solar system and Apophis's fleet, which was orbiting the sun at that time.

The dialling computer utilized by the SGC, an imperfect replacement for a DHD, is sometimes nearly the cause of disaster. Once, the bypassing of a system error (that was put there by the Ancients to prevent such a problem) caused a Stargate to introduce atoms of plutonium into the center of a star, causing the star to become unstable. Later, an unknown device and/or method was used to connect different realities and was reversed by use of an Asgard beam weapon.

Later still, it was revealed that one Stargate could be caused to dial multiple other gates simultaneously. This allowed a blast wave such as that of the Dakara Superweapon to extend almost indefinitely throughout the galaxy.

Glyphs
Glyphs are symbols on Stargates which chevrons lock onto when a Stargate is being dialled. The basis for glyphs are star constellations. There are several differences between the Milky Way, Pegasus Galaxy, and Destiny glyphs.

A Milky Way Stargate has 39 inscribed symbols on the inner ring. When dialling, this inner ring rotates until the dialled 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 and glows red. Unlike the Milky Way gates, Pegasus gates are depicted with 36 symbols. 7 symbols are still required to dial an interplanetary address, adhering to the same constraints as a Milky Way gate. Destiny's Stargate contains 36 symbols like Pegasus Stargates. The symbols are fixed on the Stargate and the entire Gate spins to dial an address. When dialling, the symbols light up to indicate they have been encoded. The glyphs are not based star constellations as with Milky Way and Pegasus Gates since the gate must be able to dial addresses from a moving point of origin in many different galaxies, but rather are some mathematical or conceptual representation yet to be discovered by the people aboard.

Ori Supergates
A Supergate is a massive Stargate developed by the Ori, spanning three to four hundred meters across. All known Supergates have been used for the specific purpose of establishing permanent footholds in distant locations in the universe, permitting the rapid passage of the Ori Army's enormous motherships across intergalactic distances.

Orlin's Stargate
The descended outcast Ancient, Orlin built a miniature Stargate in Samantha Carter's basement. Its components included 100 pounds of pure raw titanium, 200 feet of fibre optic cable, seven 100,000 watt industrial strength capacitors, and a toaster. This gate was hooked up to the main power supply of the house and only connected once, to Velona, before it burnt out.

Tollan Stargate


The Tollan were an advanced human civilization. Among their most impressive technological accomplishments was the construction of a new Stargate, built mainly with knowledge provided by the Nox.

With the destruction of the original Tollan homeworld, the Tollan's Stargate was lost. Their new homeworld, Tollana, had no original Stargate, and with the assistance of the Nox, a new gate was built.

The Tollan gate was smaller and slimmer than the Ancient's Stargates, and has a pale white color. However, it seemed to lack a DHD, or even an inner track for manual dialling, suggesting the control of it was inside a nearby building using remote dialling. Eventually the Tollan Stargate was hit by a Goa'uld Ha'tak's weapons and was presumably destroyed by the attack, as reported by Narim to the SGC.

McKay-Carter Intergalactic Gate Bridge
The McKay-Carter Intergalactic Gate Bridge was a project to place a chain of Stargates in the void between the Milky Way and Pegasus galaxies; it was initiated to allow rapid transit between Atlantis and the SGC without the need of a ZPM to power the Stargate. At the time, only the Atlantis gate had a ZPM available, meaning that the return trip from Earth required a eighteen-day journey in a hyperspace-capable Daedalus-class battlecruiser. To this end, Stargates were "harvested" from the surface or orbit of uninhabited planets and deposited accordingly on both ends. When Atlantis' ZPM was depleted, the project took on an added urgency and was made operational shortly afterward.



The bridge (named as such by its co-creator Rodney McKay, recognizing Samantha Carter for the original idea) consists of seventeen Stargates from the Pegasus network and another seventeen from the Milky Way network. A macro program written by McKay and uploaded to the gates' operating systems before dialling causes them to store incoming matter in their buffers, forwarding travelers from one gate to the next along the bridge, rather than emerging from the gate that is initially dialled.

Travelers will then exit at the Midway space station, halfway between galaxies, which serves as a transfer point. There, they will then use the other gate network (and a second macro program designed for that network) to continue on to their ultimate destination: travelers from Atlantis would use a Milky Way gate to travel on to Earth and similarly, travelers from Earth would use a Pegasus gate to travel to Atlantis. Even with this, the travel time between galaxies is just slightly over thirty minutes, making it far more efficient than traveling by hyperdrive.

When the first test of the gate bridge was conducted, only the framework of the station had been completed, so a gateship was used. The test was a complete success, and the bridge was declared operational. It was later revealed that, since the last gate in the bridge must dial the exit gate, normally either Atlantis or Earth, the macro can be rewritten to dial a different exit gate in the destination galaxy. The Midway station has since then been destroyed by the Wraith.

Asuran Stargate Satellite


The Asurans had developed an eight-chevron variant of a Stargate that was created as a satellite weapon. Its components included a shield generator, sensors and a hyperdrive, allowing it to orbit its intended target. Once this was accomplished, a wormhole was to be activated, after which an intense red energy beam reaches out and strikes the target which, in this case, was the city of Atlantis. The beam would originate from an Asuran stronghold which would both power the satellite's defenses as well as maintain an ongoing wormhole.

The satellite also had the added effect of preventing Stargate travel through the Atlantis Stargate as long as the satellite maintained its connection to the dialling Stargate, as both gates would be attempting to use the Atlantis coordinates. The satellite was able to receive the incoming wormhole from the Asurans, indicating that it could override the Atlantis Stargate, the dominant Stargate on the planet due to its being connected to a DHD. It appeared as a satellite with a Stargate in the center of its form which allowed it to manoeuvre and, thus, direct the energy weapon.

Behind the scenes

 * The Gateway Command from the series ReBoot is based off of the design of the Stargate.
 * The Time Portal featured in TimeSplitters 2, from the TimeSplitters franchise, closely resembles the concept of a stargate; although its primary function is time travel, opposed to transportation.
 * The prop of the Universe Gate located in the Destiny Gate Room set does not actually spin, only the front of it does.