# How can there be more than 39 stargates when each gate needs a unique “point of origin”?

It is shown in Stargate that there is a limited number of chevrons in each gate. Since we need a chevron for the origin point at the end of each "dialup", it can not be more origin planets than chevrons (e.g. 39).

Since there are obviously more than 39 planets shown on the TV show, how could the series be so long? How could it last long enough long to even Atlantis and Universe?

EDIT: Note: this is not a duplicate of Is there any indicator as to how many planets have Stargates? because there an estimation of the number of stargates is requested, and here the question is about how could that number be so high when you need Point of Origin chevrons and there are not so many different PoO chevrons available.

• Answered here scifi.stackexchange.com/a/2405/5297 – Binary Worrier Aug 5 '14 at 7:29
• It is not answered there, but thanks, it was an interesting reading. What I want to know is: if there are 39 possible signs in stargates, there could not be more than 39 origin planets. Am I right? – Envite Aug 5 '14 at 7:47
• @Envite - Each gate only has one unique symbol. All the others are standard across all gates. Think of the DHD as your cellphone keypad and the unique symbol as the green call button to initiate the call. – Valorum Aug 5 '14 at 8:12

Each gate contains 38 standard symbols as well as a single unique PoO symbol (Point of Origin). The 38 symbols are used as a way of addressing the gate with the 39th symbol acting as the final command to the stargate to begin the dialling sequence.

This means that each Stargate has 38 common chevrons and one different from all other gates.

As you can see, the standard DHD matches up with the standard gate. The unique symbol is the only one that's new (on both the DHD and the gate) and is the reason why the teams need a few seconds to work out how to dial home, despite knowing Earth's location.

The mapping system used is described in some detail in the stargate film (along with a helpful diagram)

DANIEL : ** And uh...to find a destination within any three dimensional space, you need six points to determine the exact location.

[Daniel draws a cube and places a dot in the center of each of the six "sides" of the cube and then draws lines between them all to intersect at a spot in the cube.]

WEST : You said you needed seven points.

DANIEL : Well, no, six for the destination. But to chart a course, you need a point of origin.

[He draws a point some distance from a cube and then a line to where all the cube spots intersect.]

• Wouldn't that seventh point also need a set of coordinates for itself. Also why would one need a set of 6 coordinates for a 3D system, 3 coordinates would suffice, wouldn't they? – Rick Sanchez Aug 5 '14 at 7:45
• @KushtrimP. - The diagram suggests that you need to locate each point, then draw connective lines between them. The destination gate is at the centre of that grid. And yes, I'm aware that that makes no sense. – Valorum Aug 5 '14 at 8:09
• @KushtrimP. Planets move, presumably "center" is a simplification and you're really just defining the area in which the gate can be in. You can see the results of this when considering what happens when multiple gates are in the same basic area--one of them has to cut off the others. (Presumably the point of origin knows its own co-ordinates, because that's where it is. I don't know why it isn't implicit, but interface design is hard) – Phoshi Aug 5 '14 at 8:51
• @Richard: To be perfectly honest, the whole chevrons on the gate don't make any sense either, since you don't need them for dialing. This is like having an old dial-operated phone with an attached number pad for dialing. So you'd enter the number on the keypad, which would cause the dialplate to rotate to establish the connection. Well, this sounds really technologically advanced and similar... Great, I'll never ever be able to watch Stargate again without having to think of that old dial sound knack knack knack... :D – Mario Aug 5 '14 at 8:52
• @Holger The address keeps getting longer until you enter the point of origin "terminator"; such as 8 cheveron addresses to other galaxys. To be honest given how the "point of origin" thing doesn't make any sense I have always thought of it as each gate has a terminator cheveron but they are all different for purely artistic reasons (as in in-universe artistic reasons) – user20310 Aug 5 '14 at 9:49

From what I gather the are 39 symbols and 6 chevrons for most gate addresses (the maths stays the same for longer addresses ) as the 7th chevron is fixed.

This means that was have 39C 6 (mathematics for out of 39 choices pick 6 Combinations.

Mathematically, this is calculated by saying once we pick symbol one we have `n-1` choices, after we pick symbol two, `n-2` choices. This continues until we get `n-k` choices where we stop. Where k is our number of chevrons, and n is our number of symbols. We now have, `n!/ (n-k)!` , e.g `39*38*...*33` We also need to discard correction sets that are the same besides order, so we divide as well by `k!` which is the number of ways we can order a set a k items (following a similar logic as above)

This lead us to having this formula

And if we plug those numbers into Wolfram Alpha we get 3,262,623. Which is how we can have so many stargates.

• This is of no help. Each of these stargates needs to be an origin point, and the question is how could that be done if there are no 3 millions of chevrons to be used as origin point in order to dial back to Earth. – Envite Aug 5 '14 at 8:21
• Except that the final symbol must be the point of origin symbol. This means that you're choosing from a mixture of 38, not 39 symbols. Your calculation should be 2,760,681 combinations. – Valorum Aug 5 '14 at 8:26
• Its actually 1987690320 possible adresses - 38*37*36*35*34*33 - permutations, not combinations - adresses (a b c d e f x) and (f e d c b a x) are not the same. stargate.wikia.com/wiki/Glyph – Milan Halada Aug 5 '14 at 11:33
• @Uriel_SVK Given Daniel's explanation of the coordinate system in the movie, some symbols can be swapped and still have the same destination (but not all of them, so combinations isn't correct even given that). That said, while it was never retconned and is still the official explanation of how the coordinates work, other dialogue does indicate permutations is correct – Izkata Aug 5 '14 at 11:57
• @Uriel_SVK, you should add this as an answer. You can incorporate Izkata's notes about it. If we go by the original movie explanation, then swapping pairs (e.g. 1 & 2) should lead to the same destination but not swapping between pairs (e.g. moving symbol 2 to the 3rd position). This makes sense per the episode in which Carter tweaks the dialing routine. We can assume she rewrote the dialing routine to swap symbols in their pair in order to minimize the total distance between symbols during dialing (a variant of the traveling salesman problem). – Jim2B Mar 23 '15 at 14:18

Most Stargates use a normal glyph as a Point of Origin – these are not unique. Some Stargates have a special Point of Origin – these are typically thought to be unique, but might act as the same missing glyph.

In a number of episodes, it can be seen that a normal glyph is used as the Point of Origin for a planet. Knowing Earth's address, the extra lit glyph on the DHDs in Shades of Grey, New Ground, and Memento must be the Point of Origin for the respective planet. You can see that Memento's Tagrea and New Ground's P2X-416 have the same Point of Origin glyph. Thus, there does not appear to be a problem with reusing Point of Origin glyphs, and logically cannot be given the number of Stargates in the Milky Way network.

However, this raises a different issue. If a planet's Point of Origin is a normal glyph, this would mean that any other planet that contains that glyph in their address would not be able to be dialed. This would imply that a single location would not be able to reach every Stargate in the galaxy, unless under special circumstances.

Related to this is the point that Milky Way Stargates have 39 glyphs on the inner track. However, Milky Way DHDs only have 38 glyphs. Thus, one glyph from the Stargate is always missing on the DHD. In the image of Abydos' DHD, the Aquila glyph is missing (most other planets' DHDs are missing this glyph as well). We often see that Earth's special glyph appears on the DHDs of planets that use a normal glyph as their Point of Origin, including in The Tok'ra, Part 1, Cure, Memento, and Demons. This could mean that the special glyph is completely unused on those planets, that it acts as the missing Aquila glyph only on those planets, or that it is not as special as first assumed and is in fact a normal glyph.

@Richard – Izkata beat me to it; Destiny's hardware address specifically requires the symbol used for Earth's Point of Origin. It is on the Icarus Base's DHD (kind of blurry, but you can just make it out).

• Can you back this up with some pictures? Obviously it's a production error but it would still be interesting to see some evidence. It may even merit its own question... – Valorum Aug 6 '14 at 14:43
• @Richard It was a plot point of the pilot episode of Stargate Universe, Earth's point of origin was on the Icarus stargate. And aside from that, I remember what Silence describes as well - I think it was around season 2 or 3 where they zoomed in so close to an off-world gate that only about 3 symbols were visible at once, and made a point to zoom in on Earth's point of origin on that gate as well. – Izkata Aug 6 '14 at 23:32
• I have added more links to pictures now that I have the ability to do so. – Silence Aug 7 '14 at 0:05

POSSIBLE COMBINATIONS

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.

With 38 symbols, the Stargate network in the Milky Way has 38×37×36×35×34×33 = 1,987,690,320 possible addresses.

For a seven chevron address, each symbol must be unique as it is referencing a point in space; however, for an eight chevron address it is possible that the Stargate (by recognising the entry of eight chevrons) allows the reuse of a glyph within an address - perhaps each having a different meaning, such as galaxy 'area codes' - which increases the possible number of addresses:

However, not all points in space represented by these addresses have Stargates; indeed, there are sufficiently few valid coordinate sets that randomly dialling the Stargate is largely futile.

• Welcome to SFF:SE. We recommend having a look at the tour, which contains helpful hints for using the site. – Politank-Z Sep 24 '17 at 22:24
• This doesn't answer this question though. It doesn't explain points of origin at all. – Brythan Sep 24 '17 at 22:43

There is a problem of misunderstanding or confusion with the original question which the other answers do not seem to address directly.

That is that the concepts of constellation glyphs/symbols (of which there are 39 which are distributed around the rotating inner ring of the Stargate, 38 of those represent constellations, and the last one is for the point of origin) are being confused with, or not completely/accurately differentiated from chevrons (trapezoid shape created by cutting off a corner of a triangle) (of which there are 9 which are distributed around the immobile outer/main ring of the Stargate).

Once that distinction is pointed out and understood, the question is moot. But I will nonetheless continue to explain the basic premise of how the Stargate works as depicted by the TV series, since the question is based in that realm, as opposed to the feature film which provides less information and seems to contradict some aspects of what is seen in the TV series.

The 39 symbols are used as references to known locations which are used to chart a destination, and the chevrons are used to select and enter that information to open a wormhole- known as "dialling" an address/the gate.

The top central chevron seems to be used for selecting the desired glyph. When the glyph is in place under it, the chevron moves/clicks down and back up again "encoding" that symbol; which causes the appropriate actual chevron to light up. It seems as though the last chevron to lock is always the top center chevron. Therefore, presumably, if the 7th symbol is not the point of origin then it will be encoded on the next chevron, and the same for the 8th symbol. At that point, the next symbol must be encoded/locked onto the top central chevron because no more chevrons remain unused on the Stargate.

There is a discrepancy in the TV series involving the point of origin glyphs. Most of the Stargates of other worlds do not actually seem to have a unique point of origin glyph, in fact at least some use one of the constellation glyphs as the point of origin. This seems to be a logistical art department prop issue (only two Stargate props were made, and only one was capable of dialling- having an inner ring that was capable of rotating), basically a way to save a bunch of time & money allowing them to recycle footage of the gate dialling by not having to design a unique glyph and replace it on the Stargate and DHD for each world.

Although, I think it's clear that we are supposed to believe that there is a unique point of origin glyph on each Stargate, and it was hoped that it wouldn't be a major issue that there actually wasn't.

It should be noted that there actually were unique point of origin glyphs created for a few worlds, but that really was rarely relevant to the plot, so it was "glazed over".

So, to recap: the first 6 symbols of a gate address specify the location (or a location vector of an 8 symbol address) and they must be comprised of the 38 constellation glyphs. For an 8 or 9 symbol address, the 7th and 8th symbols must also be one of the 38 constellation glyphs. Except for 9 symbol addresses (if now than one exists), the last symbol much be the point of origin. For a 9-symbol address it seems as though it may be possible for the 9th symbol to be any of the symbols on the gate.

The symbols on the Stargate are "encoded" using the chevrons- in other words: the chevrons are used to select and dial the symbols of an address. The number of symbols used for an address corresponds to the number of chevrons used to dial that address. Since each Stargate has 9 physical chevrons, it is possible to dial addresses using up to 9 symbols.

The pilot of Stargate Universe creates an impossible scenario of a stargate apparently having an additional point of origin symbol, and hence an additional symbol or it only has 37 constellation glyphs. Additionally bizarre and unlikely/impossible is that the extra point of origin symbol is that of Earth, but not the original glyph for Earth designated by the Ancients; the glyph for Earth found on the Stargate supplied by Ra. This is obviously a "detail" not considered by the writers, or one that they choice to ignore, hopefully without fully realizing the magnitude of the implications and how it undermines the very basis of how the Stargate system works.

• There is an answer in there, but there's also a lot of commentary (not uninteresting; just not always relevant) stuff in here. I suggest you edit your answer to focus more on the bits that do actually answer the question. – Jenayah Oct 3 at 6:10

From a production stand-point, I suspect every gate was originally going to have a full 9 chevrons (encoded numbers, not moving parts) but due to budget concerns they could only animate 7. As for in-story, it seems to me that the "Point of Origin" is merely the symbol which represents the galaxy in which the gate happens to reside. Since most of the gates in SG-1 had the "A" symbol as the final glyph needed to complete dialing of the gate, it makes it much more likely that it is the "name" of the galaxy. Another reason I suspect this to be true is the fact that, in order to dial another galaxy, it was necessary to add an eighth glyph to the dialing sequence. This would seem to suggest that the gate within a galaxy only need the seven glyph address to connect to each other while connect "long-distance" to another galaxy requires an "exchange code". It is like when you call long distance from the US you have to dial a 1 first.

The 9th glyph apparently was only needed for gates that are in motion as a sort of tracking number kind of thing.

Since the final glyph is a reference to the galaxy that the gates (origin and destination) are in, it makes sense that there could be many more than simply 39 gates in the universe. I suspect that, if the gates ran out of galaxy locators (the final glyph to be encoded), the Ancients would have built new gates with more glyphs and reworked the system to include even more chevrons on each gate and in each gate address.

• Hi, welcome to SF&F. This seems very speculative; is this just a personal theory, or do you have some evidence for this? Even the idea that for production reasons the number of chevrons was reduced from 9 to 7 isn't supported... Please read How to Answer. – DavidW Nov 19 at 18:54