Why did the gate close when SG-10 opened it from their side (the black hole), but did not close when Stargate Command dialed back into the black hole planet minutes later?

The Gates supposedly draw power from both sides, it should have the same effect, right?

3 Answers 3


I believe the in-episode explanation was that when SG-10 dialed, the black-hole was still forming, and hadn't quite exerted enough force/provided enough power to the gate to have it stay open 'perpetually'.


  • When Carter sped up the transmitted gate code she sped it up (I believe) 600%, which is when the computer recognised it as SG-10's code.
    • The gate stayed open for about a minute or two, after which it shut down. Carter remarks at some point that it could've only been open for a few seconds from SG-10s perspective.
  • Later, when they send through the M.A.L.P., They were receiving about 1 frame per 15 seconds of telemetry, which meant that the gate was closer to the black hole than it was previously.

Perhaps it (the Stargate) passed some sort of threshold where it started absorbing direct power (enough to sustain itself) from the black hole between these two events .

  • I felt it had something to do with the gate using time from the destinations perspective, or the command to shutdown from inactivity comes from the destination.
    – Arcath
    Commented Oct 10, 2016 at 13:57

I'd say the simple solution to this is "time". While I think I remember them saying the Stargate might be somehow powered by the black hole, I'd just blame time dilation for this. I don't think it can be a power problem alone due to the 38 minutes rule.

I assume that the wormhole only collapses if both gates are inactive and without power/turned off, because some energy seems to be transferred in addition to travelers (there have been episodes where they arrived at a gate that hasn't had any working power supply).

So once they turn off the Earth gate, the "Black Hole" gate should shut off too. However, this doesn't happen immediately anymore due to dilated time, which causes the wormhole to stay active for a "bit" longer. In a similar way the 38 minutes rule doesn't apply, because for the remote gate this timespan hasn't passed so far.

In the first case (SG10 trying to get home) the effect isn't strong enough to be noticeable (other than in the form of the screwed up transmissions), but it changes later on.

  • The gates can transfer energy to each other; it's possible for one gate to fully supply the other, although it requires enormous power to do so (and the dialing gate needs to make the initial connection on its own). Likewise, the 38-minute rule can be bypassed entirely when a strong enough power source (like a black hole) is used - which has happened multiple times in the series
    – Izkata
    Commented Jan 19, 2013 at 2:01

This question is addressed later on in the show when someone discusses the alterations that have been made and the safety systems that have been circumvented by the "Jury-Rigged" dialing device built by Major (then Captain) Carter. It was stated that the dialing device has a means to detect such an (gravitational) anomaly and immediately disengage. Presumable the disengagement is almost at the very instant of connection so there is never enough time to fully establish a wormhole. This feature is something akin to the VSWR management system in high end radar systems. If there is a detected back-feed the transmission circuits shut down before the magnetron can ruin itself with reflected energy.

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