Quite obviously, the Stargate is the most vital component of the TV show of the same name, but what exactly is a Stargate, and what does it do?
A Milky Way Stargate (it’s important to distinguish it from other gates) has 39 symbols, and potentially any seven of these can be used to dial another Stargate, elsewhere. In theory, there are nearly two billion (yes, billion) possible gate addresses, but in reality, this number is much smaller – as not every possible address will work (a relief if you write out your address book by hand!).
A gate address is based on a seven-point coordinate system (hence the seven symbol address), which is six points within a cubical region of space (at the centre of which is the destination), plus a point of origin. The point of origin is the seventh and final symbol entered into the address sequence.
Once a destination is dialed, a one-directional wormhole is established between the two gates – it is not possible to step into an incoming wormhole and reach the other side (in fact, doing so might kill you – a probe in an episode of SG1 – I can’t for the life of me remember the name of the episode at the moment – fell back into an incoming wormhole and appeared to be destroyed)
When a wormhole forms, there is initially an unstable vortex that projects from the Stargate. This vortex instantly vaporises anything in its path, and it would appear that there is no defence to this (in SG1’s tenth season episode ‘The Pegasus Project’, an unstable vortex forming out of a huge supergate destroys a shielded Ori warship).
Whilst matter cannot pass back into an incoming wormhole, radio signals and electromagnetic signals can. This is important; it allows a group on one world to remain in contact with people on another world, provided both parties are near the Stargate. Information (such as video signals and telemetry from unmanned drones) can also be sent back through an incoming wormhole.
Other effects can transmit back through an incoming wormhole, with potentially terrifying results.
When the SGC dialed up a planet in ‘A Matter of Time’, in a bid to contact a team they had grown concerned about, they unknowingly connected to a gate that was on a world being torn apart by a newly formed black hole. Whilst Stargates are supposed to shut down automatically after 38 minutes (an element of wormhole mechanics), the tremendous energy being supplied by the black hole was keeping the connection going. To make matters worse, the gravitational pull of the black hole (including time dilation effects) were being felt through the wormhole at the SGC!
The eventual ‘endgame’ would have been earth being sucked through the Stargate! However, the introduction of an explosive detonated at the point of entering the outgoing wormhole triggered the connection to ‘jump’ to another gate, thus saving the earth.
The amount of energy needed to power a gate connection doesn’t seem to be too extreme, given that the US Air Force was able to rig generators to power the Stargate. Power requirements increase with distance though – dialing a Stargate in another galaxy (something I will come to in more detail later) requires the use of much greater power sources – such as Zero Point Modules (ZPMs).
Stargates can also channel a lot of power – to a point. In SG1’s ‘Redemption’, Anubis uses a device to transmit energy into the gate at the SGC. The build up of energy is gradual, but the gate cannot be shut down, and doesn’t shut down even after the 38 minute time limit. The gate would have eventually exploded with the force of a two gigaton bomb, devastating the US state of Colorado, and having environmental consequences for the entire planet.
What we learn from this is that a gate can store a lot of energy, but as with all things, there is a limit.
There seems to be a fair difference between the strength of active Stargates and inactive ones. An inactive Stargate can be damaged by low-yield shots from small drones (this happens in SGU, in an episode whose name I forget). Active gates can be dropped into suns and not only survive for a brief time, but remain functional (SG1 ‘Exodus’).
They can also survive prolonged exposure to intense cold. A Stargate found buried in Antarctica (‘Solitudes’) had been there for millions of years, and was not only intact but fully functional).
Differences between Stargates
Gates from different galaxies have slightly different characteristics. Milky Way gates have chevrons that glow red when a symbol is dialed, and the inner track that the symbols spin on is mechanical in nature. Gates in the Pegasus galaxy have chevrons that glow blue and the inner track doesn’t spin – the symbols light up instead. Interestingly, though the Pegasus gates appear to be more advanced, they cannot be dialed manually – whereas Milky Way gates can, in the event of an emergency. The gates in SGU are arranged a little differently.
In some cases, a gate can be used to journey not only from one planet to another, but from one galaxy to another. This requires a power source well beyond that usually connected to a gate – and therefore such trips are rare.
The discovery of a ZPM (zero-point module) by Jack O’Neill and SG1 in ‘Lost City’ allowed for a mission to the mythical city of Atlantis, located on a world in the Pegasus galaxy. The expedition that ventured to Atlantis didn’t have anything at their disposal that could fully power the city or the Stargate, given the power requirements of both.
Interestingly, the Atlantis gate itself was programmed (via a master control crystal) in such a way that it was the only gate capable of dialing earth and the Milky Way.
Strategic and Tactical uses
It goes without saying that the gates have a lot of potential uses on a tactical and strategic level. One government/empire with access to a gate can send forces through it to another world instantly, even if that world is on the other side of the galaxy. You don’t need costly ships and transports to get troops from one location to another, and you can do it very quickly. In theory, this grants any side with access to a Stargate a tremendous advantage – but only in theory.
Gates can only remain open for a maximum of 38 minutes at a time, and they represent bottlenecks too – their locations are usually known to everyone on any given planet and since they can be easily defended (a few machine gun emplacements and a smattering of troops around the gate could pick off people coming through quite easily) they are not the best means of attacking another world. They are useful for recon work – a small team could infiltrate an enemy world and bring back valuable intelligence, or carry out acts of sabotage. Another option would be to send weapons of mass destruction through gates – but this will only be effective at hurting enemy military or political installations if the gate is near such installations.
Another problem is that any options you have for attacking an enemy force are options your enemy has for attacking you. They could easily send spies to your worlds, and carry out acts of sabotage against you. In the end, whilst gates are useful for small-scale assaults or infiltration measures, there is still the need for ships to carry large armies.