This question is not about wormhole direction as covered by Entering an Active Wormhole from the Destination. This scenario is about an outgoing gate (dial out) where the person/ship that dialed enters the event horizon from the other side of the gate.

When people dial a gate, they generally enter from the 'front' of the Stargate. On most planets, the front of the gate is the end that faces toward the DHD. It is the side that has the 'kawoosh' splash out effect.

Even when space gates were seen in Atlantis, we get treated to a scene where some Wraith Darts are guarding a gate, but they only defend one side:

Wraith darts guarding a Stargate in orbit

What happens if a person or object entered from the 'back' of an active, outbound gate?

  • 1
    I've wondered this myself in the past. It's very obvious that people cannot enter the Stargate from the other direction, but I don't personally understand the in-canon reason for this. I would assume that since the matter stream is only travelling in one direction, attempting to enter it from the wrong direction would be both unsuccessful and potentially harmful. Hopefully someone who understands the physics of the Stargate universe better than myself can take a look at your question, but I do know that it is definitely not possible to enter the 'Gate from the reverse-side. There are even case Aug 16, 2013 at 7:42
  • Didn't they mention trying that in the show? The characters' reactions implied that it was NOT an option.
    – acolyte
    Aug 16, 2013 at 15:53
  • 1
    The reason has to do with the interface to the wormhole being on the ACTIVE side of the stargate. This is the control interface where programming and reduction of the target matter is converted and directed through the wormhole. Behind the wormhole is the destructive energy needed to direct and control the matter stream. There is nothing going on back there but the energy needed to make the wormhole connection. Think of it like TV. On the front are the pretty pictures. On the back are the electronics and electricity necessary for the device to work. Touch the wrong part and die. Aug 16, 2013 at 21:58
  • 3
    @Thaddeus - if that's true, and it is that dangerous at the back, why have it open to the air? Why not have a reverse iris, or back plating, or at least enclose some of it at the back, if the whirlpool phenomenon which Jack B Nimble talks about might happen. Its not like the Ancients retrofitted their cities, and left dangerous wires hanging everywhere, everything was designed from the ground up to be aesthetic and (relatively) safe. Usually the only problems that occurred happened because of Tau'ri meddling or interfacing
    – Robotnik
    Aug 17, 2013 at 4:12

2 Answers 2


The tie-in novel SG1: Survival of the Fittest addresses this briefly.

"How about we just try it backwards?" Jack piped up again, though where he took the air from was anybody's guess. "Just because we've never done it before doesn't mean it won't-"
"I once knew a man who thought the same as O'Neill," Bra'tac reminisced dryly. "His death was most unpleasant."
"Thanks for clearing that one up, Bra'tac. What do we do? Carter?"

  • 5
    I have the strong feeling this conversation (although not the situation) was also in an episode; I remember it, but have never read any of the novels.
    – Izkata
    Aug 17, 2013 at 5:23
  • I've taken the liberty of including the actual quote rather than just a synopsis.
    – Valorum
    Nov 7, 2018 at 8:00

In the original Stargate movie we see a brief shot of the back of the Stargate just after it has been dialed.

enter image description here

We can see that the Stargate doesn't have the dialers on the back. It's surface appears to be fairly clean. Which shows there is definitely a front side. The shot then goes back to the front view, which shows the classic water surface effect that is in your screenshot. The back of the Stargate is presumably still a swirling spiral of water, focused down to a point (the point of the worm hole).

I imagine attempting to enter from the backside would be like trying to swim up through a whirlpool.

It could be figured that if you attempted to walk from the backside to the front side through the cone, you would be "pulled" backwards through the portal and out the "entrance" of the destination gate. Exiting from the backside of the gate would be impossible.

enter image description here

  • 1
    I would have to guess that the swirling whirlpool would act similarly to a kawoosh - matter interesecting it would be torn apart. Interestingly, a few times in the series we see stargates with the backs flush against another surface (notably when O'Neil was stranded in 100 Days).
    – Jeff
    Aug 16, 2013 at 17:26
  • 4
    IIRC, the swirl on the back was dropped at some point early on in the series. I think it only reappeared when they first connected to the black hole and its gravity distorted the wormhole.
    – Izkata
    Aug 16, 2013 at 23:27
  • 1
    Perhaps the vortex in the back is a symptom of non-optimal conditions; the wormhole itself being fine, but requiring more energy to overcome instability before settling into a usable state. Aug 17, 2013 at 3:11
  • 2
    @gate_engineer I'd buy that. The Earth gate was misaligned due to not having a DHD for so long, with Abydos and Tantalus being the only accessible gates...
    – Izkata
    Aug 17, 2013 at 5:27
  • 3
    The vortex in the back doesn't stay there. If you watch the whole scene, the ka-woosh comes out the front, then you get the vortex in the back, then the vortex in the back subsides back into the "pool of water". The end result is (presumably) a flat pool on both sides. The overall effect is like the water is "stretching" back as the ka-woosh goes back into the gate.
    – Omegacron
    Feb 23, 2015 at 21:55

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