We know that stellar drift is a factor in gate addresses, and this is why the only gate Earth could reach is Abydos (and the one on the planet where Catherine's husband was), and after this, they found a list of Stargate addresses.

Because of Stellar Drift, none of these addresses work anymore. Sam eventually writes a program which can account for stellar drift and presumably give them an address they can dial. This has different ramifications, because if Sam's program gave them different addresses they could dial to reach the old addresses, and the 'Gates automatically correct for stellar drift, wouldn't the original addresses work on the 'Gates in the network while the new addresses work only for Earth's gate?

1 Answer 1


It's not the addresses that need correcting, it's the control system.

SGC built their own dialing system from scratch. They don't (until later, and not even long then) have one of the dial-home devices that they often use when they're on other planets. Those DHDs have systems that automatically maintain the Stargate for optimum operation, including accounting for and updating their information for stellar drift.

The original Stargate program on Earth had no such capability because they assumed just getting the thing to work at all was "working as intended", and that the addresses were the only information involved or needed. It wasn't; either the gate or the DHD also kept stellar cartography information that allows the dialing system to work, and avoids little things like putting a wormhole through a sun. McKay says in a later episode that they ignore a whole bunch of error codes the Stargate is sending them because they simply don't know what they mean and wouldn't know how to react. It causes them other problems later on down the line.

From 48 Hours:

McKAY: The Gate wasn't meant to be used without a dialing device. Your computer system ignores 220 of the 400 feedback signals the Gate can emit during any given dialling sequence. It is a fluke that you picked up the buffer warning. For that matter, I'm surprised that you even bothered to abort the dialing sequence despite the error.

CARTER: What is that supposed to mean?

McKAY: I've read the reports, Major. You've ignored error data and bypassed dialing protocols on several occasions to get a lock.

Put another way, it's probably accurate to say the address symbols on the gate aren't actually coordinates, but represent coordinates... and it's those underlying coordinates that need tweaking.

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    @Benjamin - they had a computer interface to the gate, and originally knew just enough to send basic dialing commands, engage chevrons, etc. etc. I don't actually know if they're rewriting the Gate's database actively or just keeping it on their mainframe and sending the relevant info as they dial. The latter would be more cautious and in line with military thinking. Either way, they wouldn't know how to do it until they got the idea to actually try. Keep in mind they found the gate with only one combination; that they stopped with that one working makes sense in context.
    – Radhil
    Commented Jan 24, 2018 at 14:49
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    Could you put some specific references in this answer? Not that I'm disputing what you put; I just want to be able to look up more about it.
    – Harris
    Commented Jan 24, 2018 at 18:24
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    @HarrisWeinstein I want to say most of the discussion about Earth's dialing computer is in Season 5's Red Sky, because that's the one where it's obvious their duct taping has caused serious harm. Some of it is also in an episode where Teal'c gets trapped inside a stargate because the event horizon cut out too soon (found it, apparently also Season 5, 48 Hours). Admittedly it's been too long since I've watched the show. I will edit in some citations as I get time to verify them.
    – Radhil
    Commented Jan 24, 2018 at 18:32
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    I always viewed the addresses as phone numbers, they even have out of country codes for dialing distant galaxies
    – Pliny
    Commented Jan 25, 2018 at 1:05
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    One additional note: The S7 episode Avenger 2.0 referred to the collerative update program, a subroutine in the DHD whereby they randomly dialled other Stargates at long intervals to transmit updated coordinates or operating system changes. It's likely (though I believe unconfirmed) that each DHD tracks it's own stellar coordinates and transmits updates to the other DHDs when necessary.
    – Xono
    Commented Jan 25, 2018 at 1:40

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