In Stargate, it is said multiple times that you can only go through it in one way. All objects (radio frequencies can pass though) trying to go backward are disintegrated (sort of?).

So, what happens if you place your stargate horizontally and upward (the vortex opening up) and someone tries to go through your stargate? I imagine that the person will appear briefly, before going back though the vortex due to gravity, and so will be disintegrated immediately... no?

Would it be a good defense? Not as good as the iris, but much simpler, as you only need to rotate the stargate when you want to use it.

I remember in the SG-1 episode Hundred Days where Teal'c goes through one stargate that has been buried and needs a rope to climb out. But I don't remember if they mention what will happen to him if he falls.

  • You void your warranty and the Ancients won't fix it unless you pay a surcharge.
    – Valorum
    Oct 26, 2019 at 11:16

2 Answers 2


What happens

Exactly what you'd suspect.

This did happen in the episode you remember: "A Hundred Days", from SG-1's third season. Jack is trapped on an alien planet after a meteor hits the planet's Stargate. SG-1 has a hard time establishing contact, because it turns out that the gate has fallen horizontally; they send a MALP through, but it just falls back into the event horizon as soon as it arrives, and is destroyed.

Davis: MALP should be arriving at the Edora Gate in three...two...one. Receiving telemetry.

[The screen goes blank]

Davis: No wait, wait. We've lost it. There's no signal.

Hammond: What's happening?

Davis: Transmission interrupted at the source.

Carter: Play back the visual. Woah, there. See?

[the screen shows a cave has been burrowed out of the rock by the vortex]

Teal'c: The Gate is horizontal as you thought, Major Carter.

Carter: And the MALP just slipped back through the event horizon. It means the vortex would have dug partway to the surface.

Stargate SG-1 Season 3 Episode 17: "A Hundred Days"

The reason Teal'c needs to go through with a piton is exactly that: he needs to keep himself suspended above he event horizon, or else he'll be vaporized.

Would this be a good defense?

It would be better than nothing, but not nearly as good as an iris or coverstone. If you buried your gate in a horizontal position, you're still vulnerable to someone doing what Teal'c did: hanging inside the cavern created by the vortex, and digging their way out. Granted Teal'c probably wouldn't have made it out if Jack hadn't met him half-way, but it's a demonstrable flaw.

If you had it sitting out unburied, then there are at least two ways someone could successfully use it to get to your world:

  • Self-propelled machines. Stargate: Atlantis introduced us to the Puddle Jumpers and Wraith Darts, both of which are small enough to fit through an active Stargate. You also wouldn't be able to prevent UAVs (which SG-1 uses on occasion) or rockets/missiles from getting through

  • Jumping. This seems like a facetious comment, but we've seen that the Stargate preserves your momentum. In theory, someone could jump into their Stargate, and their arc would carry them far enough over the edge of yours that they'd arrive unscathed. It would be dangerous, but theoretically possible.

  • And so, could it be used as a defense mechanism?
    – max pnj
    Feb 16, 2016 at 16:49
  • 1
    @maxpnj Well, yes, but it's not foolproof. Evidently Teal'c was able to get through, but even if you just had it sitting in the open air, you wouldn't be able to prevent someone with sufficient velocity (either self-powered, something like a UAV or a Puddle Jumper, or simply jumping through with enough of an arc to clear the gate). It's better than nothing, and you could do things to make it more effective, but you'd have an easier time just piling rocks onto the thing Feb 16, 2016 at 16:55
  • The iris is far better as an horizontal door can't prevent climbing with a rope, sending a missile or whatever but its much simpler than creating an iris 1 micron from the event horizon... and so other planets not so technologically advanced could use this method...
    – max pnj
    Feb 16, 2016 at 16:59
  • 3
    I've always wondered why they didn't send a small c4 charge through on that episode to clear the rubble. Any rubble that fell back on the gate would be vaporized.
    – DGM
    Feb 16, 2016 at 18:19
  • 2
    You could also defeat a horizontal stargate with a ship.
    – Ellesedil
    Feb 16, 2016 at 19:05

A true DHD would have a failsafe to prevent making a connection. Since the SGC made their own version of the DHD bypassing many safety protocols they were eventually able to make a connection. So is it possible, yes. Is it possible for the average gate traveler, no.

  • 2
    Can you provide any sources to support your answer?
    – Edlothiad
    Oct 26, 2019 at 5:53

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