Ripple Effect

Summary | Analysis | Notes | Characters | Questions | Production | Transcript | In the Making | Review

Multiple SG-1s show up at Stargate Command, leading the "real" team to conclude that they have each been inadvertently displaced from different parallel realities.

FAN RATING - 8.51 
NIELSEN - 1.8 
DVD DISC: Season 9, Disc 4
STORY BY: Brad Wright & Joseph Mallozzi & Paul Mullie
TELEPLAY BY: Joseph Mallozzi & Paul Mullie
DIRECTED BY: Peter DeLuise
GUEST STARS: Teryl Rothery (Janet Fraiser), JR Bourne (Martouf), Gary Jones (Sergeant Harriman), Bill Dow (Dr. Lee), Lexa Doig (Dr. Lam), Dan Shea (Sgt. Siler), Trevor Devall (Voice of Kvasir)
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An unscheduled off-world activation has summoned General Landry and Dr. Lam to the control room. As the Stargate prepares to open, there is a brief, blinding flash of light and an odd noise. SG-1, dressed in their black uniforms, comes through the gate. Landry notes that they are early.

A briefing follows, during which a number of discrepancies come to light. Before they can be resolved, there is an off-world activation. SG-1 (in green uniforms) arrives right on schedule. Landry orders Lam to investigate. They conclude that both teams are really SG-1, but that the facts indicate that the green SG-1 is ours. (The black team, for example, believes that the Tok'ra Selmak is still alive.) Back in the conference room, Landry and the green team discuss the situation.

In need of more information, a series of interviews takes place. Black team Jackson is interviewed by green team Mitchell; Landry speaks with the black team Mitchell; green team Jackson takes notes in his discussion with the black team Teal'c. Meanwhile, green team Carter and black team Carter talk science as they try to sort out what caused this problem.

As the green team Carter briefs Landry and the rest of the green team SG-1 – she suggests the beachhead black hole the Ori tried to create ("Beachhead") is involved in bringing another SG-1 here from a parallel universe – there is another unscheduled off-world activation. Assembled in the control room, the green team and Landry watch as another SG-1 team, taking fire and dressed in blue tiger camo, rush through the gate. Landry orders all gate travel restricted.

While Dr. Lee discusses the situation with the green team Carter, the black team Carter joins them. As they work, more SG-1 teams arrive. Eventually, Landry takes the green team Jackson and Teal'c to a room where Dr. Janet Fraiser awaits them. They are stunned, as our universe's Fraiser was killed two years ago ("Heroes, Part 2"). She reveals that her Earth is suffering from the Ori plague. Also on this team is Martouf, who Landry takes to see the green team Carter, now working on the problem with at least 16 other Carters. As green team Carter sits talking to Martouf – who she was forced to kill several years ago ("Divide and Conquer"), black team Carter approaches and delineates the problem and a potential solution.

The green SG-1 and Landry confer with Kvasir, who comes in Thor's place, about a risky plan that involves using Prometheus to close the breach in space that has diverted so many SG-1 teams. Unfortunately, all of the teams will then be stranded permanently.

Fraiser visits Landry to ask for more time to find a better solution. Sympathetic, Landry feels, however, that he must act first and foremost to protect his own reality.

Staffed only by the green and black SG-1s, the Prometheus heads off. But the black team soon launches a plot to take command of the ship by breaking into the armory. Armed with zats, they capture the green team Mitchell and take him to the bridge just as the Prometheus is in position to launch its Asgard-primed weapon to close the breach.

The green team is taken to a brig while the black team re-routes the Prometheus to Atlantis in the Pegasus Galaxy. Their intent is to steal the Atlantean Z.P.M. and drop off the green team on a habitable planet. As soon as Teal'c destroys the camera in the cell, the green team hatches a counter-plot.

Green team Mitchell asks to speak with the black team Mitchell. The black team feels that the Atlantis Z.P.M. is only used to power the Stargate for one-way travel to the Pegasus Galaxy. They need the Z.P.M. to power the Ancients' Antarctic weapon, suggesting they do not fully understand the situation on Atlantis and the need for the Z.P.M. to cloak the city from the Wraith. Green team Mitchell realizes that the black team created the entire situation to come to our universe deliberately – and that they already have a way home.

Once the green team Mitchell is back in the cell with the green team, Carter short-circuits the door controls and she and Jackson set off for the engine room, while Mitchell and Teal'c head for an armory. As they try to open the armory door, the black team Jackson and black team Teal'c show up and prepare to take green team Teal'c captive once more. It's a trap: the green team Mitchell is really the black team Mitchell.

But before they can touch Teal'c, green team Carter and green team Jackson arrive and zat black team Jackson and Teal'c. Our SG-1 anticipated the trap from their other selves, and set one of their own. The black team is taken to a holding cell where the door cannot be short-circuited; black team Mitchell is dressed only in T-shirt, underwear and boots. Green team Mitchell, similarly clad, locks the door on them.

Green team Carter works out a plan for returning the many SG-1s to their respective universes, and upon the return of the Prometheus to Earth orbit she requests the use of an Asgard weapon. They fire it into the open Stargate, recreating the conditions the black team used to cause the breach.

Starting with the black team, the teams are sent back to their realities. On the ramp, the black team Mitchell stops and enigmatically tells the green team Mitchell that, when the time comes, "Cut the green one."

Finally, the last team assembles. After Carter, Jackson, and Teal'c share an emotional goodbye with Martouf and Janet, Landry provides them with the cure to the Ori plaque and the team heads home to save its Earth.

- S. Fetter


  • The first hint that the black-uniform SG-1 was not our SG-1 – other than the fact that they returned early with no explanation as to why – is the planet they came from. Our SG-1 had been sent to a planet with a designation beginning "P4R," formerly under the control of Baal; the black team came from PX7-455, formerly under Amaterasu. Clearly the black team never intended to hide the fact that they are from a parallel universe, but rather intended to make it clear who they were and convince our team that they had come by accident.
  • Dr. Lam notes that Baal is able to produce adult clones of himself – something that is only speculation at Stargate Command, as they don't know for a fact that Baal has cloned himself, let alone cloned himself multiple times ("Ex Deus Machina"). We've only found his research notes.
  • In the black team's universe the Tok'ra are monitoring the inroads made in our galaxy by the Ori. Are the Tok'ra in our universe doing the same thing, now that the Goa'uld have been defeated?
  • Cameron misspeaks in giving the designation of the black team's planet of origin. In the first act Mitchell says it is PX7-445; all other references to the planet confirm that it is PX7-455.
  • SG-1 has directly encountered parallel realities on at least two previous occasions: Daniel used the quantum mirror (not knowing what it did) to visit an Earth under siege by Apophis in the Stargate Program's first year ("There But For the Grace of God"), and the same technology later allowed SG-1 to help free another universe from Apophis's control shortly after its conquest ("Point of View"). The team has also received a note through the Stargate from an alternate future, which the note helped to avert in our reality ("2010").
  • Black Daniel and Mitchell are right in their responses to being questioned by our Mitchell and Landry: based on SG-1's experience, the S.G.C. they were in could have been an elaborate alien deception. SG-1 woke up in a fake S.G.C. six years ago, only to discover they were being tricked by the Goa'uld Hathor ("Out of Mind"). And last year, a team from Atlantis was manipulated by aliens to think they were back on Earth (Atlantis: "Home").
  • In the black team's universe, all Jaffa were united under Bra'tac after the defeat of the Goa'uld and the Replicators at Dakara ("Reckoning, Part 2"). Carter was married, though we do not know to whom. After the Ori failed in establishing a beachhead in our galaxy ("Beachhead"), they tried again and succeeded. They have so far destroyed Chulak, Dakara, and most of the Jaffa strongholds.

    It is notable that, where the Ori succeeded in invading our galaxy, they began their campaign with the Jaffa. The Priors have made similar efforts to control this powerful, yet widespread and diverse group in our reality ("Beachhead," "The Fourth Horseman").

    Bra'tac and the Jaffa of our universe are now monitoring the location where the second beachhead appeared in the black team's universe.
  • Another universe apparently has several Free Jaffa among the ranks of Stargate Command. At 27:50 a version of Mitchell walks out of the elevator and down the corridor along with three Jaffa wearing matching uniforms, who appear to be on his team.
  • The wormhole through which the black team travelled to get to our universe passed through the black hole created by the Ori's failed attempt to invade our universe (and theirs) ("Beachhead"). The Carters theorize that this caused a rupture in subspace, creating a rift in the space-time continuum that brought the other teams to our universe.

    The deviation appears to be one-way, as no one travelling from our universe – even to PX7-455 – is being sent to another universe.
  • Mitchell refers to the black team as "Bizarro SG-1" – a reference to Superman lore, where everything is backwards in the Bizarro world.
  • Why no entropic cascade failure, like Dr. Carter experienced when she came through from another reality in "Point of View?" Dr. Lee theorizes that the proximity of the various universes to one another may have contributed to the absence of the phenomenon. That is to say that because the different team members' realities are so similar (relatively speaking), so close to one another within the metaverse, they would be less likely to suffer the painful phenomenon.

    If correct, this would indicate that entropic cascade failure has more to do with the dissimilarity of two versions of the same person than with the mere fact that two of them are in the same universe at the same time.
  • A more "nerdy" version of Samantha Carter can be seen in the background during one of Carter's conversations with Dr. Lee in the lab, thick-framed glasses and all – probably a nod to the Carter from an alternate future in the Season Eight finale, "Moebius."
  • The quantum mirror was, in fact, destroyed, as General Hammond indicated he would order six years ago ("Point of View"). It was irrelevant to the current situation anyway, as it would be virtually impossible to locate the correct universe for even one other SG-1 team – let alone 16.
  • The brown camo team's Earth is suffering from the Prior plague that our Earth only recently survived ("The Fourth Horseman, Part 2"). But there the plague has spread much further, infecting hundreds of thousands of people and now threatening to wipe out the planet's entire population. But we have shared our cure with them; assuming it works from one universe to another, they can still save the people of Earth.
  • In the brown camo team's universe, Martouf and Janet are members of SG-1 along with Colonel Mitchell and Daniel Jackson. Samantha Carter and Martouf previously had a relationship, and he even joined the Stargate Program on Earth to be closer to her. They lived together for some time, but their romantic relationship ended and now she is with someone else – though Martouf didn't tell her who. She is also on maternity leave from the S.G.C.
  • The Carters theorize that a powerful enough explosion on the sending gate's side (in the black team's universe) caused the destination end of the wormhole to "skip" to a different gate, just as their shaped charge did in "A Matter of Time." But because the wormhole was bisecting the black hole at the time, it skipped to the same gate in an alternate universe rather than a different gate in the same universe.
  • The Carters' original plan was to detonate a charge inside the singularity to try and force the rift in the multiverse to close. The only way this could be done (by ship) was to use a time dilation device (delivered by the Asgard) – presumably to get close enough to the black hole to launch the explosive device, since time slows down in close proximity to a singularity.
  • The Prometheus can be operated by the most minimal of crew, as we have previously seen in such episodes as "Prometheus" and "Prometheus Unbound."
  • Mitchell warns the black team's Teal'c that he's been practicing "those Sodan moves" – referring to his time and training on the Sodan homeworld ("Babylon").
  • The black-uniform SG-1 needs Atlantis's Z.P.M. to power the Ancient weapon in Antarctica on Earth. They deliberately caused the spacial rift in order to travel into a parallel reality (ours) in order to obtain one.
  • The black team made a lot of assumptions when they gated into our reality – starting with their iris code. Fortunately for them it was the same as our team's, and they were able to survive the trip to our Earth. The team deliberately crossed universes to steal a Zero Point Module in order to protect their Earth – assuming that the universe in which they ended up would have a Z.P.M. for them to steal. Presumably if we had not, they would have returned as quickly as possible and attempted to try again, in the hopes that the rift could be connected to a different universe.
  • Our Colonel Mitchell speculates, "You don't have beards so you're not from the evil twin universe." It's a reference to popular science fiction stories like the classic Star Trek episode "Mirror, Mirror," where characters like Spock sport facial hair in an "evil" alternate universe to distinguish them from our own version of the character. Stargate SG-1 has also done this before: Apophis sported a beard in the other universe in Season Three's "Point of View."
  • The black team Mitchell asks our Mitchell an important question: "How far would you go to save the lives of every man and woman on Earth?" It's a good point; the black team isn't evil – they are doing what they have to do to save billions of lives. Their need for the Z.P.M. is more immediate than Atlantis's need to hide from the Wraith (Atlantis: "The Siege, Part 3").
  • The Prometheus's control crystal in the engine room can be removed even when the ship is travelling through hyperspace, in order to force the ship to exit hyperspace. Jonas Quinn previously removed the crystal to disable the ship when rogue N.I.D. operatives tried to steal the ship – but it wasn't even in space then ("Prometheus").
  • SG-1 used an Asgard directed energy weapon to reverse the spacial rift. By firing it back through a new wormhole to PX7-455 (the black team's point of origin) it caused the disruption to invert on itself. Each SG-1's trip to our universe, in theory, left "inter-universal pathways" that could be retraced, allowing each team to return home in the order in which they arrived.
  • The black team's Mitchell told our Mitchell, "When the time comes, cut the green one" – likely foreshadowing an upcoming episode.
  • Sam is on maternity leave in a parallel universe – a nod to actress Amanda Tapping's own maternity leave in 2005, which saw her absent from Season Nine's first five episodes.


  • The multiverse theory of quantum physics, to which Samantha Carter subscribes due in large part to the team's experiences with the quantum mirror, indicates that everything that can happen does happen in some universe. There are an infinite number of universes in our "metaverse," and new individual sub-universes are being continually generated with each choice that we make.
  • Though it feels instantaneous, a trip through the Stargate takes an average of 0.3 seconds – for matter to travel from one wormhole to another within our galaxy. The black SG-1's trip was measured at 3.4 seconds from their universe.
  • The S.G.C. computer has the ability to measure the amount of time it takes for matter to travel from a sending gate to ours.
  • Carter theorized that the first alternate team's trip created a ripple effect from the black hole that is affecting other realities. Our universe was the hub; gate travel within our universe was apparently unaffected, but any wormhole to Earth in another universe that passed close enough to the black hole was rerouted to our universe.
  • This problem didn't just affect SG-1. Over 50 teams were turned back when they trialed to dial in, not all of them copies of SG-1.
  • Thor and Heimdall are dealing with a "most sensitive matter" in a neighboring galaxy.


  • Samantha CarterSamantha Carter - Carter was faced with an astrophysics dilemma of catastrophic proportions, and managed to solve it in fine form. She had help from some 17 different versions of herself – though between parallel universes, android duplicates, and Replicators, it's not something entirely out of her realm of experience.

    Sam did get a chance to see her good friend Janet Fraiser (though from a different universe)again, and learned that in another reality she has a successful love life and a child. She also had a relationship with Martouf, who left the Tok'ra and joined the S.G.C. to be close to her, though their relationship didn't last. Carter has missed Martouf, who she liked but with whom she was never able to pursue any kind of serious personal relationship. Our Sam may well be left wondering what might have been for her.

    Our Sam nearly kissed Martouf. Is she not involved with someone, as she hinted to Agent Barrett several weeks ago ("Ex Deus Machina")?
  • Cameron MitchellCameron Mitchell - Half a year after joining the Stargate Program, this is perhaps Mitchell's most unusual experience to date. He met his first pants-less Asgard, as well as several different versions of himself from other universes – one who duped him and tried to steal his ship. He was even challenged – by himself – on the ethics of doing whatever it takes to save Earth from the Ori.

    Cameron once liked a girl named Amy Vanderberg, but never got to second base with her. He also has an aunt named Emma – or at least someone he knows as "Aunt Emma."
  • Hank LandryHank Landry - Landry was forced by a very unenviable situation to act to protect the interests of our Earth and our universe, even if it meant sacrificing hundreds of billions of lives in other realities by not getting the other SG-1s home. But Colonel Carter's solution relieved him of the situation, and he was able to send one of the teams home with the cure to the Ori plague.
  • MartoufMartouf - Though our Martouf died more than five years ago, in a parallel reality he has survived. This Martouf left the Tok'ra and joined Stargate Command to be closer to Samantha Carter, with whom he was romantically involved. The two even lived together for some time, but ultimately it did not work out. He remains a member of SG-1 in that universe, helping to defend our galaxy from the new threat of the Ori.
  • Janet FraiserJanet Fraiser - Our Janet Fraiser is dead, but in a parallel reality she survived the fight on P3X-666. With Samantha Carter on maternity leave in her universe, she is apparently an active member of SG-1. Faced with the probability of being trapped in our universe forever, Janet pled with General Landry to do whatever it took to get them home. Now she has returned to her universe, bringing with her the cure to the Ori plague that is decimating her Earth.
  • Daniel JacksonDaniel Jackson - Daniel had a chance to visit with Dr. Janet Fraiser, another universe's version of his good friend who was killed in our universe two years ago ("Heroes, Part 2"). This Janet survived because Daniel managed to get her out of the line of fire, something that must nag at our Daniel.
  • KvasirKvasir - Kvasir is an intellectual and conservative Asgard, a curt and no-nonsense scientist. He is also somewhat arrogant when it comes to dealing with humans, and tends to pontificate. He did his duty helping out the Asgard's human allies, attempting to inspire them with a speech – and ultimately making sure that the Asgard got their advanced technology back when Earth was done with it.


  • Was the black team able to in any way pinpoint a specific reality to gate to? If not, were they just hoping that we would have a Z.P.M.? Is this something we could duplicate?
  • Now that Gerak is gone, will Bra'tac assume the role of central leadership over the Free Jaffa Nation in our universe, as he did in the black team's?
  • If her father Jacob (Selmak) did not die in the black team's universe, did Sam marry Pete Shanahan?
  • Will the Ori succeed in establishing a second beachhead in our universe, as they did in the black team's universe?
  • Did the ripple effect affect any other travelers, going somewhere other than Earth? Could there be people from parallel realities now stranded on various worlds in our universe?
  • Where are Thor and Heimdall, and what are they doing?
  • Did all the versions of SG-1 make it back to the correct universes?
  • To what was the alternate Mitchell referring when he told our Cam to "cut the green one" when the time comes?
  • Will there be any lasting effects on space-time from the disruption?


  • "Ripple Effect" was originally known as "Convergence" early in the production phase, but was renamed because the name was deemed to similar to the Stargate Atlantis episode "Conversion." It was at one point also called "Echoes," then "Merge," before its final title was decided.
  • The effect of multiple copies of actress Amanda Tapping ("Samantha Carter") showing up on the screen at the same time was done using a new motion control system called "Mo-Sys." The camera pans the set with the actor in one location. For the next pass the computer pans the set exactly the same to find where the actor would be in the next position. This process is repeated as many times as necessary to provide the number of duplicated characters.
  • Actor JR Bourne ("Martouf") makes his first Stargate appearance in more than five years, since Season Four's "Divide and Conquer." The writers originally hoped to bring back a not-quite-dead Martouf in Season Five's "Summit" and "Last Stand" two-parter, but the actor's unavailability forced them to rewrite the subplot as Martouf's surviving symbiote, Lantash, inhabiting the body of someone else.
  • Actress Teryl Rothery makes her first return to the show following her character's shocking death in Season Seven's "Heroes, Part 2." At the time the writers believed that Season Seven would be the show's last year.
  • "Just last week we were discussing a story that (if everything falls into place) might see the possible temporary return of a dearly departed character." (Executive producer Joseph Mallozzi, in a message at GateWorld Forum)
  • "I started beating out an outline for our next script (tentatively titled 'Convergence') that, if all goes as planned, may see the return of a much-loved, sorely-missed character." (Executive producer Joseph Mallozzi, in a message at his blog)
  • "Brad [Wright] is still very much involved in SG-1, sitting in on all of the story meetings and providing notes for all of the scripts and cuts. The script I'm working on now, 'Convergence,' developed out of an idea he pitched out last year." (Executive producer Joseph Mallozzi, in a message at GateWorld Forum)
  • "I haven't felt this good about a script since I completed 'The Ties That Bind' and, maybe, that's cause for concern. There's a lot in this episode for the diehard Stargate fan to enjoy including a couple of interesting guest stars." (Executive producer Joseph Mallozzi, in a post at his blog)
  • "It's a fun episode with plenty of complications, twists, humor, and mini-revelations. All of our main characters have something to do and have their opportunity to shine. It will be an episode that fans, both new and old, will enjoy." (Executive producer Joseph Mallozzi, in a message at GateWorld Forum)
  • "'Ripple Effect' – well, can't say much without giving this one away but, suffice it to say, we'll see plenty of Carter in this episode." (Executive producer Joseph Mallozzi, in a message at GateWorld Forum)
  • "Now this one is a confusing script. The concept meeting clocked in at a little over three hours!" (Executive producer Joseph Mallozzi, in a post at his blog)
  • "The two hour Extras Meeting had to be a record. The stunts meeting, on the other hand, lasted a grand total of thirty seconds – so there's another record right there. To top off the day, we finished with the Visual Effects and Playback meeting. Whooweee. Try explaining the science behind this episode in a nice, neat, concise manner. And I thought time-travel episodes were confusing. Suffice it say, however, we're working with some brilliant people and I have the utmost confidence in Krista, our Playback Supervisor, to come up with some kick-ass graphics that will effectively explain it all – or die trying.

    "The Visual Effects portion of the meeting took about another two hours, but Peter [DeLuise] and Michelle Comens (our VFX Producer on SG-1) came up with some very cool shots and sequences for the various scenes. This episode is going to be a lot of fun." (Executive producer Joseph Mallozzi, in a post at his blog)
  • "We started production on 'Ripple Effect' on Monday. After seeing the first day of dailies, I had to give Peter DeLuise a call to tell him how much I loved what I'd seen. Especially Kvasir. He's a hoot." (Executive producer Joseph Mallozzi, in a post at his blog)
  • "I read a report that the mystery character I've been referring to with regard to this episode will only be appearing in flashbacks. Let me be clear. There are NO flashbacks in 'Ripple Effect.'" (Executive producer Joseph Mallozzi, in a message at his blog)
  • "Was down on set yesterday for 'Ripple Effect' and checking out Mo-Sys. It's going to look great." (Executive producer Joseph Mallozzi, in a post at his blog)
  • "Paul and I finished our prod cut of 'Ripple Effect' and the episode looks great. As I thought, I had to lose a couple of scenes (the Lam-Landry walk and talk opening, and the Mitchell-Daniel 'debate' on the ship), but hopefully you'll get to see the scenes – or, at the very least, read them when I post them after the episode airs." (Executive producer Joseph Mallozzi, in a post at his blog)
  • "I just finished up my latest installment of the 'In the Making' series, a big, three-page behind the scenes look at 'Ripple Effect' which includes most of the scenes and sequences that didn't make the final cut. It's not secret that I love this episode and am interested in seeing what kind of response it gets tomorrow night." (Executive producer Joseph Mallozzi, in a post at his blog)
  • "Although my head nearly exploded writing the script, I still have nothing but the fondest of memories for this episode which finds multiple versions of our team creating havoc at Stargate Command. Twin SG-1s team up to close the breach that has created the problem, but it turns out that one of those teams has a hidden agenda. When our SG-1 suddenly find themselves in trouble, they turn the tables on their captors the only way they can: by thinking like themselves." (Writer / producer Joseph Mallozzi, in a post at his blog)