# 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.

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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.]

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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 finally if we plug numbers in:

Which equals 3,262,623.

That is how we can have so many stargates.

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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 – Uriel_SVK 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

I cannot post more than two links, so I have only linked to the most important things.

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.