It's been a few years since I've seen anything relating to the Stargate, but what I recall from the show is that the episodes go something like this:

  1. Stargate team jumps through the gate to another world
  2. The inhabitants of that world have a problem
  3. ???
  4. Entertainment!

All well and good...but that gets me thinking, why doesn't anyone ever come through Earth's Stargate?

The Goa'uld could certainly benefit from a surprise attack in the middle of their base, especially since they have superior technology to Earthlings, and spaceships that could traverse the distance to invade should they render the Stargate inoperable - they have nothing to lose from an attempt.

But even if we don't include the Goa'uld, why don't other species ever cross through the gate in the same way humans constantly hop through to visit other worlds?

  • possible duplicate of Is there any indicator as to how many planets have Stargates?
    – calccrypto
    Sep 4, 2014 at 13:50
  • 8
    Low chance of finding Earth, and also the iris
    – calccrypto
    Sep 4, 2014 at 13:51
  • 11
    There's also the issue that Earth's gates have been buried and inoperable for thousands of years, so nobody would know they could dial Earth until SG-1 starts making headlines. Sep 4, 2014 at 14:07
  • 9
    The series began with that exact situation. Apophis & his troops launched a surprise attack on the Cheyenne Mountain facility. It was because of this that the iris and IDC system was installed. Kind of like putting locks & a peephole on your door AFTER someone walks in and takes your stuff, but oh well.
    – Omegacron
    Sep 4, 2014 at 20:28
  • I'm at work and without time to go searching for references, but offhand I can think of a couple occasions where the SGC was invaded despite the iris, a couple where they were contacted by an unknown (one of these explicitly mentions how unlikely it is to randomly dial another gate at all), and several where they were contacted by an ally (usually the Tok'Ra)
    – Izkata
    Sep 5, 2014 at 16:21

2 Answers 2


Short answer: they try.

Long answer: enter image description here

They can knock, but it doesn't do them much good.

Without a GDO, the Iris, a large shield millimeters beyond the event horizon that prevents the typical Ka-Woosh (Carter gives a throwaway explanation at one point) and will prevent the reintegration of matter. O'Neil describes it as 'bugs on a windshield'.

In the early episodes of season one, there's an episode where the gate activates off-world, no GDO is used, and a series of bangs is heard. Teal'c and Jackson are watching the gate, discussing what Apophis might be sending through.

Daniel doesn't like the idea that lots of Jaffa just splattered against the Iris, but he likes being invaded a lot less.

The iris is installed while SG-1 is away for the first time (before they even meet Teal'c) and is later replaced by an even stronger version.

Atlantis had a similar thing, but it was a transparent force-field. Unauthorized travelers splattered, but were just flashes of light.

Edit: In response to other species -

Other humans do try to use the gate from time to time. Most use it to travel between a few known addresses (often for trade). Of those who try random addresses, well, they have a very low chance of finding Earth.

It did happen once, in the episode called 'The Other Side'. The people who traveled through the Stargate didn't make it...but the radio call to see if they survived did, and the SGC warned them against sending anyone else through. They established friendly contact, and SG-1 went to visit them. It ended...badly.

Edit: As Matt pointed out in the comments, the Iris prevents the Kawoosh, it doesn't close after it.

  • 15
    Also because its an amusing piece of trivia GDO stands for "Garage Door Opener". :)
    – Chris
    Sep 4, 2014 at 15:34
  • 3
    It's also worth noting that there were several occasions on which people did come through the gate, including villains and including (initially) successful attacks on the SGC.
    – Brian S
    Sep 4, 2014 at 16:26
  • @BrianS: True. The Tollan can walk straight through with their phasing abilities, the aliens from 'Foothold' got in somehow (not shown), and a few others have been able to project things into/through the iris (including Anubis who tried to blow up the stargate with subatomic particles).
    – Jeff
    Sep 4, 2014 at 17:25
  • 4
    Im pretty sure it closes before the Ka-Woosh.
    – Matt
    Sep 5, 2014 at 3:55
  • 2
    @Matt - Agreed. I remember Sam Carter throwing a one-liner at one point about how 'the IRIS prevents the splashout effect because it's too close to the event horizon'
    – Robotnik
    Sep 5, 2014 at 5:13

First, the is a protective shield, the Iris, as Calccrypto noted in one of the comments. Probably in case of a serious attack that could penetrate the Iris, the Stargate itself could be destroyed, making attacks through it futile (although could be a good way to leave the SG team without the resource of their Stargate).

Second, many of inhabitants of worlds with Stargates seem to be unable or unwilling to use them. So although there's many Stargates, there are not that many travelers or "traffic". Actually, many of the visited worlds seem to host cultures less advanced that Earth's, unaware of other worlds or the possibilities of the Stargate.

Third, I seem to remember from one episode that there is actually a second Stargate on Earth, much older and buried in one of the pole's ice. This could mean that most of those able to use a Stargate lost memories of Earth through huge spans of time.

  • 3
    The Antarctic gate was Earths original gate, buried after the Atlanteans left, so there would have been a long period of time where Earth would have been unreachable. Its quite possible that any gate travellers would have made note to do use the gate during this time and shared that knowledge. Earth didn't get it's second gate until Ra brought one to Earth to make slaves of the people.
    – Amicable
    Sep 4, 2014 at 16:23
  • Good point about "unable or unwilling". The implication is that the Earth Stargates were forgotten for thousands of years, at least from the time of the Ancient Egyptians ~2,000 BC until the early 20th century. Knowledge of such devices, to the extent that such still circulated, had passed into mythology and legend rather than science or engineering. Feb 26, 2019 at 13:28

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