Astrophysics and Carterisms

Stargate Wormhole

Astronomy, Wormhole Physics, and Carterisms

Here are some observations on how Stargate SG-1 presents the physics and technology behind the Stargate, as well as other aspects of astronomy and planetary physics, with some reality checks and observations about the consistency of series canon thrown in.

Written by: Blue Cove, 2004
Status: Complete Through Season One

Stargate, The Movie

What is the Stargate, and how does it work?

Discovered in Giza, Egypt, in 1928 by Catherine Langford's father. It was buried under a cover stone engraved with both inner and outer tracks. The inner track is hieroglyphs, while the outer track is symbols no one understands at first.

The name "Stargate" is a direct translation, at least according to Daniel.

Tests date the Stargate as being over 10,000 years old, before the rise of Egyptian civilization.

Although a team worked for two years on deciphering the cover stone, it takes Daniel only two weeks to realize that the symbols on the outer track aren't hieroglyphs, but are in fact star constellations. These same symbols are found on the Stargate itself.

NOTE: Although this sounds really clever, from an astronomical standpoint it doesn't make sense. Constellations are artificial constructs, imaginary lines drawn through various stars to remind us of a person, animal, or object. The problem is, although certain stars appear close together from our perspective, they may in fact be hundreds or thousands of light years apart. Trying to designate a single point in space using an entire constellation is therefore impossible.

Stargate addresses consist of seven symbols, with six used to determine an exact location in space and the seventh used as a point of origin.

By the time Daniel comes on board the Stargate project, a computer dialing program has already been created. The movie never shows us a dialing device, or tells us how the team manages to dial home from Abydos.

Originally, when the Stargate was opened the entire control room vibrated. Also, travel through the wormhole (and the change from matter to energy and back) left travelers with a sheen of frost on their faces. Both of these ideas were later explained away or simply dropped as impractical for the series.

The gate is made of a mineral unlike any found on Earth; presumably, it's the same mineral being mined on Abydos. In the series, this mineral is called naquadah.

Season One

1.01 "Children of the Gods"

What's in the episode:

Daniel has found a cartouche room filled with what appears to be a number of Stargate addresses. This is their first indication that the Stargate can go to other places. The problem is, Sam's team back on Earth (which created the dialing program) have tried other combinations of symbols, and nothing ever worked. Sam theorizes, pointing to "the expanding universe model" as a reason why the original coordinates would have changed over time. Abydos must be closest to Earth in the Stargate system, which is why that address still works. All they would have to do is "correct for Doppler's shift," and they should be able to make the adjustments necessary for the addresses on the map to work again. She adds that "any civilization advanced enough to build this gate network would be able to compensate for 50,000 years of stellar drift."

The SGC creates an iris, a barrier made of pure titanium, which they are confident will keep unwanted guests from coming through the Stargate.

What it means:

Several different terms are thrown at us in this scene:
- The expanding universe model basically says that, ever since the Big Bang, the universe has continued to expand. Galaxies, stars, and other objects are all moving away from each other, and the further away they are, the faster they appear to be moving.
- The Doppler shift is named for Christian Doppler, and is used in the field of meteorology as well (i.e. Doppler radar). It says that energy waves, including light, will produce different wavelengths and colors (on the spectrum), depending on the motion of both the source and the observer. The faster and closer to us something moves, the more it produces short, blue-shifted waves; the slower and further away it is, the more we see long, red-shifted waves. In this way, it's possible to tell whether an object or event is approaching or moving away from us, and how quickly.
- Stellar drift, at least in this case, refers back to the expanding universe model, meaning that the positions of the stars are different now from what they would have been when the Stargates were created.

Put everything together, and Sam is saying (with an assist from Daniel) that the set of addresses in the Cartouche room might not be valid now, because the star(s) designated by each symbol on the Stargate wouldn't be in the same place after thousands of years of movement. An adjustment would have to be made, taking into account where the star(s) would have been thousands of years ago, and what is there now. (This is where the Doppler shift analysis comes in.) The work has to be done manually in the case of Earth's dialing program; presumably, Stargates attached to DHDs would make their own corrections.

NOTE: Sam theorizes that Abydos is the closest planet to Earth in the Stargate network, and that's why an adjustment for stellar drift wasn't required in order to reach it. This directly contradicts the movie. In fact, the entire series, with several exceptions, takes place within the confines of our own galaxy. This approach actually makes more sense, but it's a point of contention for purists.

As Sam says, the iris is set less than three micrometers from the Stargate's event horizon. (The event horizon is the water like "surface" which provides an entrance/exit for a functioning wormhole.) Such a small distance means that matter, which has been converted into pure energy for the journey, isn't able to fully re-integrate before being splattered against it. The "thud" sounds we hear are actually masses of energy hitting the iris, not bodies.

1.06 "The First Commandment"

What's in the episode:

When SG-1 arrives on P3X-513, they learn it has a high UV radiation count. The people there were once enslaved by the Goa'uld, who were able to create a force field which blocked the radiation over a wide area. Since they left, the people have been forced to retreat to caves during the day, and only come out at night.

What it means:

Stars produce energy by fusing hydrogen into helium; one of the byproducts they give off is ultraviolet radiation. On Earth, our atmosphere blocks the worst of the sun's UV rays before they can reach the ground. The atmosphere on P3X-513 is obviously thinner, and allows more radiation to get through. As seen in the episode, ultraviolet is bad for humans - it burns the skin, as well as causing various types of cancers and even DNA damage under prolonged exposure. The shield left by the Goa'uld functions as another atmospheric layer, allowing light and heat through, but filtering out harmful UV rays.

1.11 "The Torment Of Tantalus"

What's in the episode:

An experiment in 1945 which opened the Stargate is explained by the fact that Ernest's planet is "close to Abydos, so it uses many of the same points in space locators." Somehow, the scientists hit on that particular combination of glyphs, and were able to connect because planetary drift wasn't an issue.

Once on the planet, SG-1 discovers that the DHD's central red crystal is broken. Sam says "all roads lead" there, so it must be the power source. She attempts to connect the Stargate directly to the remains of the crystal, but fails when the DHD falls through the floor and into the ocean.

With the DHD (and crystal) gone, the Stargate must be linked to another power source. Sam says that the naquadah in the gate is a superconductor, and will accept energy in many forms. The gate then converts and stores the energy in capacitor-like reservoirs, until there is enough to unlock the inner wheel and dial manually.

What it means:

The idea that both Abydos and Ernest's planet are close enough to Earth to avoid the planetary drift problem strains credulity. Although our galaxy as a whole is in motion (i.e. the expanding universe model), the individual stars and other objects within it would be moving as well. To say that three star systems, all with planets, avoided the problem by remaining close over tens of thousands of years is a bit difficult to swallow.

Evidently, when the crystal in the center of the DHD was broken, it severed the link between the DHD and the Stargate. However, there is still power within the crystal pieces. Sam believes that by connecting them to the gate and bypassing the DHD, they might be able to power up enough to dial their destination manually.

Because the gate can store energy, their power source doesn't have to be continuous (the way it is, for instance, in electrical appliances). One good lightning strike is enough to allow them to complete the dialing process and establish a wormhole.

1.15 "Singularity"

What's in the episode:

The SGC has built a small observatory on the planet Hanka in order to better observe and photograph a nearby black hole. They are particularly waiting for an eclipse, which will make such objects easier to see. Jack surprises everyone (except Sam) by knowing what an accretion disk is, although he stumbles over his explanation of a black hole.

What it means:

The existence of black holes has never been definitively proven, but the series takes as a given that once we begin traveling among the stars, we will find proof. According to theory, a black hole begins as a massive, burnt-out star which collapses in on itself. If the mass is great enough, gravity will accelerate the collapse until it forms a small, extremely dense object called a singularity. The gravity well formed by this singularity eventually begins drawing in nearby gas and dust, creating a whirlpool around it called an accretion disk. It's the disk that will show up on photographs, although presumably other kinds of readings would be taken as well.

1.18 "Solitudes"

What's in the episode:

SG-1 is returning from P4A-771 while under attack. Suddenly, the gate begins drawing an increasing amount of power, and a system error registers. Daniel and Teal'c are thrown out of the wormhole at high velocity; it then disengages before Jack and Sam can come through. The gate is repaired, and the SGC proceeds to start looking for them.

It turns out they have been sent through some other Stargate to what appears to be an ice planet. After giving the matter some thought, Sam comes up with an idea. She explains that their working theory is that the Stargate creates an "artificial wormhole" which "transfers an energized matter stream in one direction along an extra-dimensional conduit." She adds that she thinks they may have been redirected, that the gate was "struck by enough energy (from staff weapons) to influence the direction of the matter stream" before she and Jack reached the other end of the wormhole. It's probable that they would emerge somewhere in the Stargate network close to Earth.

Meanwhile, Daniel and Siler are coming to some of the same conclusions. Siler reiterates that the Stargates are "superconductors" which send "charged matter streams along lines of force between them, positive to negative." This is the way electricity operates, except a wormhole trip happens "outside our dimension."

What it means:

Let's try to untangle some of the techno babble. When SG-1 enters the wormhole on P4A-771, Jaffa are firing staff weapons at them. Some of that energy discharge hits the Stargate, and because Stargates are superconductors, this extra energy is absorbed by the gate and begins causing a system error.

According to theory, the wormhole itself is a one-way tunnel which burrows through a dimension outside our own in order to reach its destination. (In effect, it's a shortcut, which is how travelers make the journey so quickly.) SG-1 is en route to Earth, having been converted to streams of energized matter for the short duration of the trip. Unfortunately, the problem at the other end is destabilizing the wormhole. The SGC gate tries to compensate by drawing extra power, but it can't get enough, because our system isn't set up for that.

Daniel and Teal'c make it to the other side, but Jack and Sam are too far back — so, the SGC gate automatically diverts the wormhole in mid-transit, sending it to the nearest working Stargate where they can be deposited safely. This turns out to be the gate in Antarctica. Once there, Sam digs out the frozen DHD and tries to dial home. Unfortunately, it refuses to accept the coordinates for Earth, and she doesn't understand why.

After the SGC fruitlessly searches the planets between Earth and P4A-771, Daniel finally figures out that the next nearest gate might actually be here. Sam is unable to connect with the SGC gate because, although the symbols might look different, they both have the same point of origin. Therefore, they can't both be used at the same time.

1.22 "Within The Serpent's Grasp Part 1"

What's in the episode:

A large, round object is placed in the middle of the Stargate. Teal'c explains it is a long-range communication device "somewhat like your television." Later, Apophis uses it to address the crew of Klorel's ship.

When the Stargate suddenly stops functioning, SG-1 realizes that Klorel's ship has entered hyperspace, thereby stopping both them and the SGC from making a connection.

What it means:

This device doesn't seem to need an open wormhole, but appears to turn the Stargate itself into a sort of portable viewscreen. An explanation of exactly how it works isn't given.

As long as Klorel's ship is in orbit around a planet, the DHD can use that planet as a point of origin. Once the ship enters hyperspace, the point of origin is no longer valid (while in motion, there actually isn't one), and a wormhole can't be formed.

Astrophysics and Carterisms

Contents

Astronomy, Wormhole Physics, and Carterisms

Stargate, The Movie