Stargate (device)

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 a different and extinct race, the Ancients. At the climax of SG-1's 6th season, Daniel Jackson discovers that the Earth myth of

Operation

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.^[10] 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;^[11] 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.^[9] 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 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.^[11] 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.^[10] This normally feels effortless, but if the stargate has been improperly operated or is not functioning correctly, can be an uncomfortable experience.^[10]

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.^{[citation needed][12]} By "dialing" these symbols in the correct order, the traveler selects a three-dimensional destination.

• 
  Schematic diagram of a Milky Way stargate with glyphs
• 
  Schematic diagram of a Pegasus stargate with glyphs
• 
  Schematic diagram of Destiny's stargate with glyphs

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

By identifying six constellations in space, a single

Eight-symbol addresses are introduced in "

Stargate Universe introduces the concept of a nine-symbol address, the purpose of the ninth chevron never having been explored in the previous series.^[18] 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

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 "Enter" key to activate the Stargate once a destination has been dialed. Each DHD only has 38 keys, 19 on each ring. According to 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.^[19]

The

Once an address is dialed, the gate is said to have created a "stable

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".^[24] 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.^[25] 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.^[24] 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.

Making of the props

Two full Stargate

There are further Stargate props that are no more than two-dimensional or semi-three-dimensional (jar-lid shaped) Stargates, being more lightweight and easier to erect on location. These are always filmed front-on to preserve the illusion. If a shot involves the 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.^{[citation needed]}

The visual effects for Stargate SG-1 and Stargate Atlantis are predominantly produced by

The Stargate itself is nearly always filmed against a blue or green backdrop, not only making it easier to paste the vortex imagery onto the scene, but also facilitating the superimposition of the "event horizon ripple effect", which is entirely computer-generated. However, if a shot only involves an open wormhole without anyone stepping through it, the crew may choose to use a "practical puddle," which is simply a backlit screen placed in the gate displaying a video of the wormhole effect. This only works, however, on a darker set, as otherwise the projection will get washed out.^[39] 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.^[40]

See also

• Stargate Origins

References