next generation time travel episodes

Complete List Of Time Travel Storylines In Star Trek

This article is more than five years old and was last updated in December 2019.

Time travel features in over 50 episodes of Star Trek and in four of the movies, making it one of the franchise's most commonly used storytelling mechanics. This list includes all episodes the television series and the movies with time travel plots, from the original series through to 'The Next Generation', 'Deep Space Nine' and 'Voyager', as well as the movies and the latest incarnation, 'Discovery'.

Star Trek: The Original Series

Star Trek IV: The Voyage Home

Star Trek: The Next Generation

Star Trek Generations

Star Trek: First Contact

Star Trek: Deep Space Nine

Star Trek: Voyager

Star Trek: Enterprise

Star Trek: Discovery

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'Cause and Effect' and 12 more great Star Trek episodes that go all 'timey wimey'

Star Trek  loves to boldly go into the past, future, and alternative timelines. Here are some of the franchise's best trips through time.

There are more than a few Star Trek episodes that deal with time travel. Quite a few, in fact, especially when one takes into account that the Temporal Prime Directive instructs Starfleet officers not to interfere or do anything that could change history. But, thankfully for Captains like Kirk and Picard, some officers take such directives more as "strong suggestions."  

Not all of Trek ’s time travel shenanigans, however, involved messing with the historical record — Star Trek: The Next Generation ’s classic episode “Cause and Effect,” for example, deals with a time loop, one where the U.S.S. Enterprise sadly and repeatedly gets destroyed until the crew susses things out. 

Speaking of time, 30 years have passed since “Cause and Effect” premiered. To celebrate the occasion, here are 12 other great Star Trek episodes that have our favorite members of Starfleet getting entangled throughout time.  

1. “The City on the Edge of Forever” ( The Original Series , Season 1)

While later shows had their fair share of time travel, Captain Kirk and his crew also had more than one timey wimey experience. In “The City on the Edge of Forever,” Kirk’s crew stumble across a sentient archway that can send anyone to any time and place. An addled McCoy walks through it, followed by Kirk and Spock, and they end up on Earth in the 1930s. Their presence in the past changes their future, and the three have to untangle what happened, which ultimately involved Kirk falling in love with the woman who they ultimately must allow to die to set their timeline right. One of the first, truly great episodes of  Star Trek , "Forever" puts Kirk and Spock in the middle of a no-win scenario, pre-dating  Wrath of Khan : Kirk can either save his friend and the future, or the woman he loves. Not both. The good Captain tries, but his solution is a heartbreaking one. 

2. “Yesterday’s Enterprise” ( Next Generation , Season 3)

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“Yesterday’s Enterprise” involves your standard rift in space-time, and as the episode’s title suggests, it also involves an older Enterprise, the Enterprise-C, that travels through said rift and alters the timeline in its wake as it encounters a militarized version of Picard's Enterprise-D. The new timeline pits the Federation in a war with the Klingons that Starfleet is losing, and it also brings back Denise Crosby's Tasha War, who died a "thankless death" in the first season of TNG . "Yesterday's Enterprise" gives Yar a chance to die like a hero, and it also gives fans one of the greatest  TNG  episodes as Picard and Guinan debate the moral grey areas that come with sending the Enterprise-C's crew to their deaths in order to save countless lives in a future that the present needs to exist. 

3. “Tapestry” ( The Next Generation , Season 6)

The life of Jean-Luc Picard is the focus of this emotionally stirring "What if..." time travel episode, where the Captain and Q have a little tete-a-tete in the afterlife after Picard is killed by an energy surge that messed up his artificial heart.

Picard lost his original heart after getting stabbed in the chest during a brawl with aliens while he was a cadet. He has come to regret that choice in his life, which he reflects on in death, so Q decides to play a game of It's a Wonderful Life  with Jean-Luc and send him back to his cadet days to relive his past and change his future. Picard does so, but his future becomes one that is more bleak than he anticipated — he finds himself to be an unremarkable junior science officer rather than the Captain of the Enterprise. It turns out that the brawl all those years ago incident helped make Picard who he is, so he asks Q to send him back again to get stabbed in the heart. "Tapestry" puts time travel and the idea of changing one's fate through a very unique, cautionary tale-like lens, resulting in one of the best hours  TNG  ever did. 

4. “All Good Things...” ( The Next Generation , Season 7)

Picard worries about destroying all of humanity on accident in "All Good Things..." (Credit: CBS)

“All Good Things” is the Q-filled series finale of The Next Generation . The two-parter has Q still judging humanity, and he’s time-hopping Picard through three time periods — the show’s present day, 25 years into the future, and Picard’s first mission as Captain of The Enterprise. In all these time periods, a mysterious anomaly is threatening all life, and Picard has to work across timeline to fix it. It is the best feature-length adventure this crew has ever had, and it is one of the most entertaining and well-written series finales in the history of television. 

5. “Past Tense, Parts 1 and 2” ( Deep Space 9 , Season 3)

Deep Space Nine  gave us a more bleak trip through time than fans were used to with this eerily prescient two-parter. Here, Sisko, Dr. Bashir and Dax go back in time to 2024, just days before the Bell Riots, a crucial point in human history where a violent confrontation occurs in San Francisco. Sisko and Bashir’s presence there inadvertently changes history, resulting in the Federation never existing and those stuck in 2024 charged with setting things right. (Which, of course, they do.)

6. “Little Green Men” ( Deep Space Nine , Season 4)

“Little Green Men” is a fun throwback to black-and-white 1950s sci-fi, with Quark, Rom, and Nog finding themselves in 1947’s Roswell, New Mexico after a warp malfunction. The Americans think the Ferengi are Martians, and only-on- Trek  hijinks ensue, especially with Odo in the mix. He made the time travel journey as he was investigating whether Quark was moving illegal contraband (spoiler: he was). The episode's fish-out-of-water banter hits more often than not, and Armin Shimerman steals the show as Quark gets deeper in hot water with the American military.

7. “Trials and Tribble-ations” ( Deep Space 9 , Season 5)

This Deep Space 9 episode written by Ron Moore for Star Trek 's 30th anniversary celebration goes meta and has the DS9 crew sent back to another Star Trek episode: The Original Series ’ “The Trouble With Tribbles.” Here, Sisko, Dr. Bashir, Chief O'Brien, Worf, Dax, and Odo find themselves over 100 years in the past, aboard Kirk’s U.S.S. Enterprise, where a secret Klingon agent has planted a bomb amongst bins full of Tribbles. The DS9 episode re-uses footage from “The Trouble With Tribbles,” Forrest Gump -style, adds our  DS9  cast to it in a way that lets them share several delightful scenes with Kirk and the  TOS  crew.

8. “Year of Hell, Parts 1 and 2” ( Voyager , Season 4)

“Year of Hell” finds a battered Janeway and her crew embattled with a Krenim time ship, whose captain (Kurtwood Smith) is trying to adjust the timeline through temporal incursions in order to bring back his late wife. His incursions impact Voyager when they have a run-in with another Kremin ship, which sets off a battle that has the Voyager on the run for almost a year and ultimately close to destruction. A desperate Janeway is forced to take extreme measures, like crashing Voyager into the time ship, in order to erase the last year and save this part of space. "Year of Hell" is the closest fans ever got to a Star Trek: Voyager  movie, and it is truly one of the most ambitious two-parters in the franchise's considerable arsenal.  

9. “Timeless” ( Voyager , Season 5)

Voyager ’s 100th episode starts out 15 years in the future, where we see the remains of U.S.S. Voyager on an ice planet. In this future, Chakotay and Harry Kim have spent years trying to find Voyager so they can send a message back through time and warn their crew (and their past selves) about the dangers of entering a slipstream that wrecked the ship.

LeVar Burton directed this riveting, action-packed episode; he also reprises his role as Geordi La Forge during a brief encounter with Kim. 

10. “Relativity” ( Voyager , Season 5)

Seven of Nine finds herself on a temporal investigation when the Starfleet timeship called Relativity recruits her to find out who placed a temporal bomb on Voyager, which will ultimately lead to the ship's destruction. Seven’s exploits take her back to moments on Voyager before she became part of the crew, and also has her playing ping pong, among other things. "Relativity" expertly plays with the rules of Trek time travel in ways that allow for a tense "ticking clock" feel to Seven's efforts to save Voyager in the past, in order to ensure that her crew have a future. Jeri Ryan carries the episode effortlessly, and her scenes trying to convince Captain Janeway of their tricky predicament pop as the two actors' get to flex their more comedic muscles. 

11. “Endgame, Parts 1 and 2” ( Voyager , Season 7)

Credit: CBS

“Endgame” is the series finale of Voyager and starts out 30 years in the future, where we find out that after over two decades, Voyager made it back to Earth. The elder Admiral Janeway, however, wants to change the past — not everyone made it back to Earth alive; Seven of Nine died on their voyage back along with over 20 other crew members, and Tuvok’s health has deteriorated. Admiral Janeway ultimately makes her way back in time and (eventually) works with the Voyager crew to enter Borg space, take on the Borg Queen, and use the Borg’s network to get back home. 

12. “E 2 ” (Enterprise, Season 3)

While Enterprise focused on a temporal war, one of the show’s best time travel episodes involves Archer’s Enterprise traveling back over a century and then rendezvousing with Archer’s present-day Enterprise. When the two ships connect, many on board the Enterprise get to meet their descendants before the timeline is sorted out.

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Time Travel in Star Trek: The Next Generation (TNG)

"Let's make sure that history never forgets the name... Enterprise." (Capt. Picard, TNG: "Yesterday's Enterprise")

TNG: We'll Always Have Paris

This episode is full of "small" paradoxes where the characters encounter themselves in moments that are only a few seconds or minutes in the past or the future. The problem is basically the same as with the grandfather paradox, although the impact is of course less severe.

Classification: random time shifts, without visible consequences

TNG: Time Squared

In this episode Picard 2 is the only one to survive the explosion of the Enterprise. He is thrown six hours to the past together with his shuttlepod. Aboard the still existing Enterprise in the past, Picard 2 suffers from a severe shock; he initially cannot talk and doesn't remember anything. Moreover, the shuttle's computer data cannot be read out. It is clear that this is primarily a ploy to keep the situation obscure. Anyway, the effects shown here are doubtful with regard to other time travel episodes. The difficulty with the shuttle's energy signature may be rationalized with some technobabble. Picard 2's corresponding physical and mental condition, however, seems to be directly related to the current time, as if there were a temporal signature of his organism that makes him feel better the closer he is to the time of his departure (ironically, only to vanish the very moment that marks his departure to the past). This doesn't make much sense, considering that whatever is responsible for biological and electronic systems being out of phase here, the phase shift remains the same as long as they remain in the wrong, earlier time frame. What's more, there is no such effect in other episodes, only a weak similarity to TOS: "All Our Yesterdays" .

It is ethically highly questionable for our present Picard 1 to kill his ill-fated counterpart from the future. It would have been absolutely sufficient to hold him back, since "the cycle must end" , as Picard 1 notes himself. Ironically, after changing the timeline in this direction, Picard 2 disappears anyway together with the shuttle. There is an obvious paradox when the Enterprise does not explode, since in this case there is no Picard to travel back in time and warn the Enterprise.

Classification: broken predestined timeline ("causality loop"), with biological impact of time travel

TNG: Yesterday's Enterprise

When the Enterprise-C appears from the space-time rift, the ship has traveled "22 years, 3 months and 4 days" into the future, according to Data. The timeline from the instant of its departure in the year 2344 to the present of 2366 is instantly switched. It can be supposed that the Klingons regarded the disappearance of the ship from Narendra III as cowardice, which finally led to the war timeline. The Enterprise-D crew, as almost all other beings in the galaxy, are unaware of the change, even as Worf is replaced by Tasha. It remains a mystery how Guinan is able to perceive the old timeline, which has not been "simply" erased from biological and computer memories, but has actually never existed. No one would expect a biological entity to have such a supernatural ability, which is absolutely useless for its normal life. One would rather suppose that beings such as Q who move in more than three dimensions can perceive and also manipulate timelines. Maybe Guinan is not the humanoid she appears to be.

Apart from the temporal sequence, there is also a logical sequence of events.

1. The Enterprise-C defends the Klingon outpost and is finally destroyed (event 1), which is honored by the Klingons (timeline 1). 2. The Enterprise-C is "pulled" into the future of 2366 prior to being destroyed (event 2), which infuriates the past Klingons and creates the war timeline 2. The space-time rift is not a static phenomenon, but originates at event 2, since until then the old timeline 1 definitely existed. 3. The Enterprise-C is "pushed" into the past again. This allows to recover event 1, but not exactly, since Tasha is aboard the Enterprise-C. 4. The Enterprise-C defends the Klingon outpost and is finally destroyed, which is honored by the Klingons (event 1a). Some crew members, among them Tasha, are "saved" by the Romulans, only to be killed later on. However, Tasha gives birth to her daughter Sela, who will appear later in TNG: "Redemption" and "Unification" (timeline 1a).

It is not evident why the Enterprise-D is present near the very same spatial anomaly in both timelines 1/1a and 2, despite the vastly different circumstances. This was a dramatic choice, but must be rated as extremely unlikely because of the second law of thermodynamics. For the same reason, the crew of the Enterprise-D and ultimately the ship itself shouldn't be so very similar in both timelines. Unfortunately, it is not an option that the timelines could have diverged slowly (we might imagine that in 2364 an important Klingon figure suddenly made a big deal about what happened in 2344 and started the war). Picard explicitly speaks of "20 years of war" .

The even bigger problem with this episode arises retrospectively. The temporary timeline 2 should have been eliminated by sending back the Enterprise-C to the past. This would not have allowed Tasha to stay aboard the Enterprise-C, she would simply disappear at the instant the future is changed again, and Sela could never exist. Vice versa, Captain Garrett, who died in a never existing future, would come to life again (for a short time). This is an obvious paradox. Perhaps the Enterprise-C, returning from the future, is shielded in some fashion so it would not be returned to the state in which it left the year 2344.

Classification: past incursion caused by accidental travel to the future, remaining paradox (Tasha and Sela)

TNG: Captain's Holiday

Time travel is only a secondary aspect of the story, although the Tox Uthat is assumed to come from the future. However, this is one of the few episodes where a predestined timeline is established, since the two Vorgon time travelers obviously anticipated that Picard would destroy the Tox Uthat.

Classification: predestined past incursion ("causality loop")

TNG: A Matter of Time

No paradox occurs in the episode itself. However, by leaving his own time which is in fact the 22nd century, Rasmussen has probably already altered history. On a side note, it does not become clear why Rasmussen, who has a timeship from the 26th century, chose the less advanced 24th century to steal technical equipment. What's more, for an ordinary thief he seems to be too well prepared, since he knows or pretends to know a lot of details about the Enterprise. As much as he has learned about it, there should have been much easier ways for him to get hold of valuable equipment than on the well-guarded starship.

Classification: intentional past/future incursion, without visible consequences

TNG: Cause and Effect

This episode features two different kinds of time travel. First, the USS Bozeman unintentionally travels 90 years to the future, just to collide with the Enterprise. Second, the Enterprise is caught in some kind of time loop. Every time the Enterprise is destroyed, the present time for ship and crew and probably the surrounding space region returns to an instant some time before the ship's destruction from an external viewpoint. In other words, the Enterprise and her crew do not travel back in time, but time itself is not continuous within a small region of space. This is corroborated by the statement that the Federation time signal is 17.4 days ahead at the end of the episode, meaning that the Enterprise has stayed in the time loop for this long as seen from an external observer.

The phenomena in this episode can't be explained in plain language. The starting point of the events seems to be a space-time rift, potentially similar to the one in TNG: "Yesterday's Enterprise". The Bozeman is pushed or pulled into the future through this rift and almost immediately collides with the Enterprise. The explosion of the Enterprise, probably in connection with the surrounding space-time distortion, causes the time reset. We do not know if the Bozeman explodes as well or is directly affected by the destruction of the Enterprise. However, it is obvious that the Soyuz-class ship is caught in the time loop as well, since the collision occurs repeatedly. Each time the Enterprise is restored to the state that was a few hours ago, and the same must apply to the rest of the space region. Otherwise, in the second and following laps the crew would have registered discontinuities in sensor measurements. We can assume that a Federation time signal is not continuously received, although this was possible in TOS: "The Naked Time" . However, in any case the changes of remote constellations are definitely measurable and should have revealed the time reset. Since the Bozeman was not in the respective space region some hours ago, the ship is thrown back 90 years after each explosion; only this way it can emerge from the rift each time.

The story is substantially consistent if we accept the unlikely fact that humanoids have a built-in sixth sense for temporal discontinuities (déjà-vu) that Data as well as the advanced subspace-physics based equipment of the Enterprise do not detect. There is no paradox, since the repeated collisions and explosions actually happened. Still, the chance of a collision of the two starships is literally astronomical, even if we take into account that the Enterprise is somehow attracted by the space-time distortion.

Classification: time travel to the future & broken causality loop in an isolated region of space-time

TNG: Time's Arrow

There are two clear indications of a predestined timeline in this episode. First, Data's head is found in the cave before Data actually travels back to the past and loses his head. Second, Guinan pretends to know Picard for a long time, which is only confirmed "later" when Picard actually meets her in the past. If we assume that back in the past the crew create exactly the timeline that has always existed, whether they want it or not, this episode is self-consistent. Moreover, complicated explanations of switching between different timelines are not necessary, since there is only one timeline.

Nevertheless, the concept of predestination remains hard to accept because it is an offense against free will. What if Data had stayed away from the scene under all circumstances as Picard has originally planned it, in order to avert his time travel? Who could have hindered him to change history? Likewise, what if Picard had taken Data's head with him when he returned to the 24th century?

What's more, we have contradictory statements about the mechanism of time travel in this episode. After his head has been found in the cave, indicating that he will die, Data says: "There is no way anyone can prevent it, sir. At some future date, I will be transported back to nineteenth century Earth, where I will die. It has occurred. It will occur." He thereby explicitly states that the timeline is predetermined, in contrast to what happens in most of Star Trek's time travel episodes. Conversely, Guinan claims that there is nothing like predestination. She insists on Picard joining the away team, so she can meet him in the past. If everything were predestined, there would be no need for her to take any influence with her knowledge about the timeline. She also tells Riker on the topic of what he could do to save Picard who has stayed behind in the past: "If I told you what happened in that cavern, it would affect any decision you'd make now. I can't do that. I won't."

TNG: Tapestry

Q may have forged the whole scenario much like a holodeck simulation. However, if we believe Q, then Picard is given a second chance to avoid the confrontation with the Nausicaans, in the course of which he lost his natural heart. Q sends him back to his early days in Starfleet, briefly prior to the incident.

Picard perceives himself as the aged captain, while everyone else sees the young Ensign Picard. At the end of the episode, when Picard is revived (for which he is rather indebted to Beverly than to Q), it is still not clear whether his experiences in the past were true. We might tend to believe Q, who has never been so honest and sympathetic than in this episode and will never be again. In this case, the past has been slightly changed, taking into account Picard's short affair with his crewmate Marta.

Side note The authors missed a great opportunity in connection with the TNG episode "Bloodlines", where Dai Mon Bok alters a boy genetically so that he appears to be Picard's son. The boy, however, could have been Picard's and Marta's real son and this could have proved that Picard really traveled to the past.

Q's promise that Picard can change his own history without affecting other people is odd in any case: "Since you attach so much importance to the continuity of time, I will give you my personal guarantee that nothing you do here will end up hurting anyone, or have an adverse affect on what you know of as history." In order to elude the butterfly effect, Q would have to "filter" Picard's actions with selective disregard for interdependencies and fabricate a history that could not exist on its own. Q's demonstration that Picard, at his current age, would still be a lieutenant junior grade instead of captain, only because he has always been cautious, is doubtful and it insinuates that there is something wrong about the whole scenario.

Classification: multiple intentional past incursions that possibly never took place, without visible consequences

TNG: Timescape

This episode features various time levels in which time proceeds at different speeds. The time on and around the Enterprise and the Romulan Warbird almost stands still relative to the time experienced by Picard, Deanna, Geordi and Data in the runabout. The concept and effect of time levels is similar as in TOS: "Wink of an Eye" , however, the explanation is substantially different in the TNG episode. Here, the time levels are a physical phenomenon, and the effects of interaction between different time levels have to be considered on this level. There should be physical as well as biological problems for a character entering another time level. Yet, only the latter ones have are partially shown in the episode.

Further investigation of the implications shows that any interaction with a significantly different time level is virtually impossible. Firstly, light or any other form of energy coming from a slower time level is shifted to extremely low frequencies and also its intensity is significantly reduced. Geordi can hardly locate the frozen Enterprise because "energy levels are practically non-existent" , yet it is possible to see everything like it were on a normal level. Realistically, even Geordi would not see the extreme infrared light. This is due to the simple fact that one corresponding oscillation period is many times longer in the slow time level than in the fast level. Secondly, the same applies to molecular motion, so the temperature would be very close to absolute zero for persons from the fast time level, and of course extremely uncomfortable. Thirdly, it is doubtful whether it is possible to touch or move objects in the slow time level or to breathe the molecules of the "slow" air, let alone to cope with their low temperatures. Finally, even if interaction is possible, for the slow computer it should take a long time until anything is displayed. The writers could have avoided at least the latter inconsistency by somewhat slowing down the LCARS response times.

Classification: different time levels

TNG: Parallels

This is one of the most fascinating Star Trek stories ever. It focuses on parallel realities, while the time travel at the end of the episode is only a secondary aspect. The time travel probably serves to return to the original timeline in "our" universe that would otherwise have been altered by Worf's temporary absence, or another Worf's presence.

Classification: travel to another reality and back in time, without visible consequences

TNG: Firstborn

We get no idea if and how the old Alexander's appearance in the past would affect his own time and himself. The grandfather paradox is quite evident, considering that young Alexander would be warned and probably wouldn't travel back in time in his later years.

Classification: past incursion, with unknown consequences

TNG: All Good Things

Q is well-known for his fancies, and of course it is him who arranges the weirdest time travel of Star Trek so far. Maybe he takes pleasure in sending Picard on time travels since TNG: "Tapestry". Firstly, three different times in the past, the present and the future are involved, and Q arbitrarily transfers Picard from one time to another. Secondly, Picard is transferred into himself, i.e. he replaces his alter ego in the past and the future. In a "normal" time travel there would be two simultaneous Picards. Thirdly, his actions in the past do not have any bearing on the future, the three times are isolated from each other with respect to the normal forward course of time. Finally, vice versa, the captain's actions in the future do affect the past. It seems that Q employs any possible trick to bring about the anti-time reaction that destroys all mankind in the past, only to blame Picard for it. Picard is only a marionette in Q's highly unfair fancy, however, despite all off Q's attempted deception, the best Star Trek captain ever does his job.

The fact that the Enterprise is destroyed in "Star Trek Generations" might be a sign that the TNG episode does not describe an actual future, but only a future in Q's imagination. However, in DS9: "The Visitor" another possible future is shown, and the future Defiant crew wear the same uniforms and badges as on the future Enterprise and Pasteur. Apart from the obvious budget savings in the real world, this is a sign that Q's future is not inevitably the real future, but at least a realistic one.

Classification: multiple travels to multiple times, corrected or without visible consequences

Star Trek: Generations

The movie features the Nexus, a phenomenon that allows either to stay in the wonderful world inside or to travel anywhere any time. In other words, the Nexus can do everything. This quality is certainly not beneficial for the story, as it leaves too many options and too many questions. According to the Star Trek Encyclopedia II , Soran was only briefly inside the Nexus in 2293 until he was "rescued" by the Enterprise-B transporter beam. This assumption makes more sense than the theory that the El-Aurians were expelled from the Nexus by the Borg. Exactly the same as to Soran must apply to Guinan. However, while Soran seems to be outside the Nexus when Picard meets Kirk, there is a representation of Guinan left in the Nexus and able to talk to Picard.

Picard and Kirk probably chose the worst possible instant to leave the Nexus and return to reality when Soran already had his finger on the launch button. If it is true that the two could have traveled anywhere any time, they could have returned e.g. to the Amargosa Observatory. Captain Picard probably considered possible effects on the timeline, however, either he wanted to prevent the destruction of the inhabited solar system under all circumstances or not. In particular, Kirk could have chosen a better time for himself to return to reality. What if Kirk had gone back to his own time and probably changed history?

In this movie a paradox does not occur, because the Nexus probably works as a kind of buffer between the timelines. The Nexus is obviously a domain outside of our space-time, and is therefore not affected by changes in our universe. So the old timeline, in which the Veridian system and the Enterprise saucer are destroyed, ceases to exist. However, Picard is nevertheless always present in the Nexus (like Guinan), and so he is able to leave the Nexus and fight Soran in the new timeline.

Classification: past incursion to change history, successful

Star Trek: First Contact

When the Borg alter history by sabotaging Cochrane's first warp flight in 2063, the Enterprise-E is protected from the change, since the ship is already in the vortex that leads back in time. So far, the authors have learned from errors in the past when such a phenomenon almost customarily remained unexplained. When the Enterprise-E arrives in the year 2063, it is already too late to prevent the formation of a new timeline, since the Borg have begun to shoot at the launch site and have killed a number of people that might have been important for history. Picard's first idea should have been to travel back about one more day (using the slingshot effect) and immediately destroy the Borg sphere as soon as it arrives. Even without the Borg's attempt to capture the Enterprise, the success of the actual efforts to correct history is questionable. It seems to have worked though, and the Federation is the same as before, or has only imperceptibly changed.

We may want to speculate that "First Contact" features a predestination since Riker quotes the future Cochrane and Cochrane might have the quote from Riker (not to mention that Cochrane may have been inspired to name the first Warp-5 ship "Enterprise").

However, why did Geordi recreate the Borg vortex to return to the future, instead of choosing the good old slingshot effect, which is even possible with a primitive Bird-of-Prey? It is possible that the missing deflector didn't allow to go to warp, but it was never mentioned as being so crucial, so it must have been obvious to the crew that the Borg vortex was the only or the best option to go back.

A problem arises with regard to VOY: "Year of Hell", where Seven of Nine knows about the Phoenix because "the Borg were present during those events" . The first explanation could be that some Borg were still alive, or at least their subspace transmitters were functional when the Enterprise arrived back in the 24th century, and they contacted the Collective. Secondly, they could have used temporal transmitters such as in VOY: "Timeless" . Thirdly, although the modification of the sensor dish failed, a conventional subspace signal could have made it to Borg territory in the 21st century. The puzzle was retroactively solved in ENT: "Regeneration" where the Borg from the crashed sphere sent a subspace signal to the Delta Quadrant that T'Pol said would need "at least 200 years" .

Classification: past incursion to change history, corrected

Some screen caps from TrekCore .

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Fleet Yards

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Time Squared

• Episode aired Apr 1, 1989

The Enterprise comes across its own shuttlecraft adrift in space - a duplicate - with an unconscious duplicate Capt. Picard inside. The Enterprise comes across its own shuttlecraft adrift in space - a duplicate - with an unconscious duplicate Capt. Picard inside. The Enterprise comes across its own shuttlecraft adrift in space - a duplicate - with an unconscious duplicate Capt. Picard inside.

• Joseph L. Scanlan
• Gene Roddenberry
• Maurice Hurley
• Kurt Michael Bensmiller
• Patrick Stewart
• Jonathan Frakes
• LeVar Burton
• 20 User reviews
• 9 Critic reviews

• Captain Jean-Luc Picard

• Commander William Thomas 'Will' Riker

• Lieutenant Geordi La Forge

• Lieutenant Worf

• Counselor Deanna Troi

• Lieutenant Commander Data

• Wesley Crusher
• (credit only)

• Doctor Katherine Pulaski

• Chief Miles O'Brien
• Crewman Nelson
• (uncredited)
• Operations Division Officer
• Maurice Hurley (showrunner)
• All cast & crew
• Production, box office & more at IMDbPro

Did you know

• Trivia Picard admits he has trouble with waiting patiently and Riker says that it's Picard's "Persian Flaw." In traditional Persian carpet weaving, it was standard practice to deliberately put in a few mistakes, because attempting perfection might offend God.
• Goofs Before the shuttlecraft is retrieved, no attempt is made to visually/electronically identify it. Also, no attempt is made to identify its occupant's commbadge. This would be standard procedure.

[Future Picard is restrained to a biobed by a force field]

Captain Jean-Luc Picard : Release him.

Dr. Kate Pulaski : Do you know what you're doing?

Captain Jean-Luc Picard : No. Release him.

• Connections Edited into Star Trek: The Next Generation: Descent (1993)
• Soundtracks Star Trek: The Next Generation Main Title Composed by Jerry Goldsmith and Alexander Courage

User reviews 20

• Sean_Biggins
• Dec 4, 2023
• April 1, 1989 (United States)
• United States
• Official site
• Paramount Studios - 5555 Melrose Avenue, Hollywood, Los Angeles, California, USA (Studio)
• Paramount Television
• See more company credits at IMDbPro

Technical specs

• Runtime 45 minutes
• Dolby Digital

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5 Star Trek Time Loop Episodes, Ranked

• Time loop stories are a classic science fiction premise Star Trek excels at.
• Star Trek: Enterprise and Voyager had excellent time loop episodes, but The Next Generation's "Cause and Effect" is the best.
• Star Trek: Discovery had two time loop episodes, "Magic to Make the Sanest Man Go Mad" and "Face the Strange".

Time loop stories are a classic science fiction premise, and Star Trek has dipped into that well several times. Although Star Trek: The Original Series never did a traditional time loop episode, plenty of Captain James T. Kirk's (William Shatner) adventures involved time travel. Every Star Trek series since has incorporated time travel in some way, including two of the franchise's most highly regarded films, Star Trek IV: The Voyage Home & Star Trek: First Contact. Not every Trek series has done a time loop episode, but it's an incredibly fun premise that makes for great television when it's done well.

The time loop premise fits so well within the world of Star Trek , that it makes sense the franchise would return to it multiple times. Time loops (or "temporal causality loops") are apparently so common in the Star Trek universe, that Starfleet uses a time loop simulation as one of their training drills. In Star Trek: Lower Decks season 2, episode 8, "I, Excretus," a holodeck simulation called "Time Loop" was one of the possible drills the USS Cerrtos' Lower Deckers had to run, along with things like infiltrating a Borg cube or escaping the Mirror Universe. Being a Starfleet officer means being ready for anything, and here are five Star Trek episodes that trapped their characters in a time loop.

Many television shows have taken advantage of a time loop premise, with Stargate SG-1, Buffy the Vampire Slayer, The X-Files, and Supernatural all delivering particularly fun time loop episodes.

20 Best Star Trek Time Travel Episodes & Movies, Ranked

"future tense", star trek: enterprise season 2, episode 16, star trek: enterprise.

Cast Dominic Keating, Connor Trinneer, Linda Park, John Billingsley, Scott Bakula, Jolene Blalock, Jeffrey Combs, Anthony Montgomery

Release Date September 26, 2001

Streaming Service(s) Paramount+

Showrunner Manny Coto, Brannon Braga

Although not a time loop episode in the traditional sense, Star Trek: Enterprise's "Future Tense" features two different miniature time loops. When the Enterprise NX-01 finds a derelict shuttlepod from the future floating in space, the temporal radiation leaking from the ship causes time disturbances. As Commander Trip Tucker (Connor Trinneer) and Lt. Malcolm Reed (Dominic Keating) continue to examine the shuttlepod, they find themselves reliving the same moment over and over.

"Future Tense" has some fun moments, including the time loops.

Captain Jonathan Archer (Scott Bakula) and Sub-Commander T'Pol (Jolene Blalock) discover that the pod is from the 31st century and presume it must be connected to the Temporal Cold War in some way. To keep the pod from the Suliban or the Tholians, Archer and Reed try to booby-trap it but end up stuck in another time loop. Eventually Trip activates the pod's distress signal and the ship vanishes, presumably back to the 31st century. "Future Tense" has some fun moments, including the time loops, but the Temporal Cold War storyline on Enterprise never quite worked as well as it could have.

The 31st-century shuttlepod is impossibly bigger on the inside than the outside, a nod to the time-traveling TARDIS on Doctor Who .

Star Trek: Voyager Season 3, Episode 15

Star trek: voyager.

Cast Jennifer Lien, Garrett Wang, Tim Russ, Robert Duncan McNeill, Roxann Dawson, Robert Beltran, Kate Mulgrew, Jeri Ryan, Ethan Phillips, Robert Picardo

Release Date May 23, 1995

Showrunner Kenneth Biller, Jeri Taylor, Michael Piller, Brannon Braga

Where To Watch Paramount+

When a shuttlecraft carrying Captain Kathryn Janeway (Kate Mulgrew) and Commander Chakotay (Robert Beltran) crash lands on a planet, Janeway is seriously injured. Before long, Star Trek: Voyager 's villains the Vidiians find the crashed shuttle and kill Janeway and Chakotay. The two then appear again on the shuttle just before they crashed. Immediately realizing they're caught in a time loop, Janeway and Chakotay try something different, but this time, their shuttle explodes. Time resets again, and Janeway and Chakotay make it back to Voyager before Janeway is killed again.

"Coda" is an entertaining and even frightening episode, and Kate Mulgrew delivers a great performance.

In the final loop of Star Trek: Voyager 's "Coda", Janeway sees herself "die" and encounters the supposed spirit of her father. Realizing that something isn't right, Janeway refuses to go with him and wakes up on the planet as Chakotay and The Doctor (Robert Picardo) revive her. "Coda" is an entertaining and even frightening episode, and Kate Mulgrew delivers a great performance. However, the final reveal that most of the story happened in Janeway's head undercuts some of the more emotional moments.

"Magic to Make the Sanest Man Go Mad"

Star trek: discovery season 1, episode 7, star trek: discovery.

Cast Blu del Barrio, Oded Fehr, Anthony Rapp, Sonequa Martin-Green, Doug Jones, Wilson Cruz, Eve Harlow, Mary Wiseman, Callum Keith Rennie

Release Date September 24, 2017

Showrunner Alex Kurtzman

Star Trek: Discovery season 1 received a mixed reception from fans, but "Magic to Make the Sanest Man Go Mad" stands out as a solid and entertaining take on a classic premise. When Harry Mudd (Rainn Wilson) arrives on the USS Discovery, he enacts his plan to kill Captain Gabriel Lorca (Jason Isaacs) and sell Discovery's spore drive technology to the Klingons. Mudd has a time crystal that allows him to repeat the same 30-minute time period over and over.

Victorious, Burnham delivers the coup de grâce line to Mudd: "Turns out you can con a con man."

Due to the tardigrade DNA in his system, Lieutenant Paul Stamets (Anthony Rapp) remains aware of the time loops, and he recruits Michael Burnham (Sonequa Martin-Green) and Lt. Ash Tyler (Shazad Latif) to help him stop Mudd. Mudd kills Lorca repeatedly and nearly succeeds in his plan, but Stamets, Burnham, and Tyler reroute Mudd's signal to his fiancée, Stella (Katherine Barrell), and her father rather than the Klingons. Victorious, Burnham delivers the coup de grâce line to Mudd: "Turns out you can con a con man."

10 Star Trek: Discovery Positives You Only Notice On Rewatch

"face the strange", star trek: discovery season 5, episode 4.

In one of Star Trek: Discovery's best episodes so far, Captain Burnham and her new First Officer, Commander Rayner (Callum Keith Rennie) , find themselves jumping through different time periods in Discovery's past, present, and future. Like the previous time he was stuck in a time loop, Stamets remains aware of the jumps and works with Burnham and Rayner to find a solution. They revisit multiple moments from past seasons of Discovery , and Michael even encounters her past self, resulting in a Burnham vs. Burnham fistfight.

The time jumping turns out to be the result of a Krenim "time bug" that courier Moll (Eve Harlow) snuck onto the Enterprise in the previous episode.

Burnham and Rayner also get a glimpse of a possible future where the Breen ended up with the Progenitors' technology and destroyed the Federation. Thankfully, Stamets, Burnham, and Rayner prevent this future by destroying the time bug, and Discovery loses only six hours rather than the weeks it could have lost. Not only is Star Trek: Discovery season 5, episode 4 an incredibly fun episode of Star Trek , but it also shows how far Burnham and the other characters have come since the show's first season.

"Cause and Effect"

Star trek: the next generation season 5, episode 18, star trek: the next generation.

Cast Michael Dorn, LeVar Burton, Brent Spiner, Wil Wheaton, Jonathan Frakes, Patrick Stewart, Marina Sirtis, Gates McFadden

Release Date September 28, 1987

Showrunner Jeri Taylor, Michael Piller, Rick Berman

In Star Trek's first true time loop episode, the USS Enterprise-D is destroyed over and over again as Lt. Commander Data (Brent Spiner) and the rest of the crew try to find a solution. After a cold open that ends with the Enterprise blowing up, the crew members end up back at their game of poker. Although they do not initially realize they are stuck in a time loop, Dr. Beverly Crusher (Gates McFadden) begins experiencing a sense of déjà vu. After they discover their predicament, Data sends a message to himself using his positronic brain.

Wonderfully directed by Jonathan Frakes, every time loop in "Cause and Effect" feels unique.

At the end of each loop, the Enterprise collides with another ship as it emerges from a space-time distortion, after Data's suggestion to use the tractor beam fails. Data eventually realizes the message he sent himself indicates they should try Commander William Riker's (Jonathan Frakes) suggestion to decompress the main shuttlebay. The plan works and the Enterprise finally avoids the collision. Captain Jean-Luc Picard (Patrick Stewart) then contacts the other ship, the USS Bozeman, which has been missing for over 90 years. Wonderfully directed by Jonathan Frakes, every time loop in "Cause and Effect" feels unique, and the episode remains one of Star Trek's most memorable time travel stories.

Star Trek: The Next Generation, Star Trek: Voyager, Star Trek: Enterprise, & Star Trek: Discovery are all available to stream on Paramount+.

Time travel

• View history

The HMS Bounty slingshots around Sol

Time travel is having the ability to or the act of travel forward or backward in time , thus breaking the seemingly irreversible flow of time. The study of this phenomenon is one of the focuses of temporal mechanics . Alterations to historical events can cause, among other things, alternate timelines and realities .

As late as 2154 , time travel was deemed impossible by the Vulcan Science Directorate . ( ENT : " Awakening ")

The United Federation of Planets had some form of time travel ability since at least 2268 . Regulations on time travel were later imposed to prevent alterations from being made to the timeline. ( TOS : " Assignment: Earth "; DIS : " Such Sweet Sorrow, Part 2 "; DS9 : " Past Tense, Part I ", " Past Tense, Part II ", " Trials and Tribble-ations ")

In addition to the Federation, the Borg Collective , Bajorans , and the Klingon Empire were known to have some form of time travel capabilities. ( Star Trek: First Contact ; DS9 : " Trials and Tribble-ations ", " Wrongs Darker Than Death or Night "; DIS : " The Red Angel "; TNG : " Firstborn "; VOY : " Endgame ")

• 1.1 Overview
• 1.3 Temporal Cold War and temporal wars
• 2 Opinions on time travel
• 4.1 See also
• 4.2 Background information
• 4.3 Apocrypha
• 5 External links

History [ ]

Overview [ ].

Historical research in 2268 suggested the Federation was capable of controlled time travel and used this ability at the very least for research purposes. ( TOS : " Assignment: Earth ")

As of 2378 , at least forty different instances of some form of time travel had been noted in Federation records. Technologically speaking, the Federation's capabilities concerning time travel, for the most part, remained unclear.

In the 25th century , time travel was mostly possible but still risky. ( TNG : " Firstborn ")

As of the 26th century , historians and anthropologists used time-pods to travel through time to observe historical events. ( TNG : " A Matter Of Time ")

In the 29th century , the Federation had the ability to scan time as well as space, and travel back (and presumably forward) in time to attempt to fix issues and anomalies. ( VOY : " Future's End ", " Future's End, Part II ", " Relativity ")

In the 31st century , time travel was commonplace. Federation temporal agents from this time became involved in a Temporal Cold War , which eventually led to temporal wars . After these wars, time travel was banned and the technology used to travel in time was destroyed. ( ENT : " Shockwave, Part II "; DIS : " That Hope Is You, Part 1 ")

Crewman Daniels , a temporal agent from the 31st century , showed Jonathan Archer a group of time-traveling anthropologists from 2769 observing the building of the pyramids of Giza . ( ENT : " Cold Front ")

In the 2230s , Section 31 created a special Red Angel time-traveling suit in response to Klingon time-traveling studies. This suit would use a special time crystal that created micro- wormholes to travel through time. A Klingon attack forced its test pilot, Gabrielle Burnham , to use it, bouncing throughout time. Section 31 thought the technology destroyed. ( DIS : " The Red Angel ", " Perpetual Infinity ", " Through the Valley of Shadows ")

Time crystal-related technology was available outside of Federation oversight by late 2256 , when Harry Mudd procured a time crystal-powered device that allowed him to rob a Betazoid bank and commandeer the USS Discovery , while repeatedly (and creatively) murdering her captain, Gabriel Lorca . ( DIS : " Magic to Make the Sanest Man Go Mad ")

The Discovery , after being transported to the mirror universe in late 2256 or early 2257 due to Captain Gabriel Lorca 's machinations, returned to her original universe nine months later due to difficulties navigating the mycelial network . Her crew ended the Federation-Klingon War shortly thereafter. ( DIS : " What's Past Is Prologue ", " The War Without, The War Within ", " Will You Take My Hand? ")

In 2258 , the Discovery was transported via a time crystal -generated wormhole to 3188 in order to prevent Control from becoming sentient and destroying all life in the galaxy. ( DIS : " Such Sweet Sorrow, Part 2 ")

Captain Christopher Pike was transported via time crystal by his own future self to 2266 to witness the terrible future that would occur if Pike attempted to change his own fate. ( SNW : " A Quality of Mercy ")

The USS Enterprise first experienced time travel in 2266 , when an emergency cold start of its warp drive slingshot the ship and its crew seventy-one hours into the past. ( TOS : " The Naked Time ")

In 2267 , after an encounter with a black star , the Enterprise was hurled three hundred years into the past. Eventually, the Enterprise 's science officer Spock devised a method for returning the Enterprise back to its original period. ( TOS : " Tomorrow is Yesterday ")

Later that year, officers Kirk , Spock, and McCoy traveled to Earth 's early 20th century and back via the Guardian of Forever . ( TOS : " The City on the Edge of Forever ")

Sometime in 2268 , the Enterprise traveled back in time, using the light-speed breakaway factor , to 1968 , on a historical research mission. ( TOS : " Assignment: Earth ")

Time warp effects experienced by Kirk and crew

In 2286 , Admiral James T. Kirk and his senior staff took a stolen Klingon Bird-of-Prey back in time to the year 1986 , to retrieve a pair of humpback whales , a species which was extinct by 2286, to save Earth from destruction by an alien probe . ( Star Trek IV: The Voyage Home )

In 2371 , Captains Jean-Luc Picard and James T. Kirk used the Nexus as a means of controlled time travel, going to just before the destruction of the Veridian star, which Picard intended to save. (Picard arrived at the Nexus from just after the destruction of said star, whereas Kirk arrived from some seventy-eight years before .) ( Star Trek Generations )

Data , unknowingly at first, traveled back in time to Earth 1893 while investigating an alien species that was later found to be ingesting the neural energy from Humans of that time period. The aliens acquired their sustenance by traveling through a portal back to that time and place from Devidia II , and were able to shield their presence from outsiders by being slightly out of temporal sync with everyone else, disguising their presence further by taking advantage of a local cholera outbreak. Picard, Riker, Crusher, La Forge, and Troi soon followed to retrieve Data and assess the situation. As the Enterprise crewmembers covertly endeavored to stop the aliens and return to their own time, Samuel Clemens was suspicious of them, and was accidentally sent to the 24th century with the Enterprise crewmembers (except Picard) when they used the alien portal to return to their own time. Clemens managed to go back through the portal and retrieve Picard, returning each man to his own time period before the Enterprise destroyed the aliens and their portal. ( TNG : " Time's Arrow ", " Time's Arrow, Part II ")

Twice, Q took Picard back in time. The first time was when Picard lay dying in a starbase medical facility during a replacement of a defective artificial heart that he had received as a result of a Nausicaan knife being stabbed through his heart immediately after Picard had graduated from Starfleet Academy on Starbase Earhart . ( TNG : " Tapestry ") The other example was to the beginning of life on Earth , and also back and forth in Picard's lifetime. ( TNG : " All Good Things... ")

During a transporter accident above Earth caused by chroniton particles being accidentally fused to the hull of the USS Defiant , Benjamin Sisko , Julian Bashir , and Jadzia Dax were sent back in time to the early- 21st century , just before the Bell Riots . This caused the Federation and Starfleet to vanish in the present, after the time travelers ' interference led to the death of Gabriel Bell before he would have played a crucial role in history. Only the Defiant was left protected by the chroniton particles. Sisko took on the identity of Gabriel Bell to ensure that he was remembered for saving hostages during the events, and ultimately allowing the Federation to come into being over a century later. ( DS9 : " Past Tense, Part I ")

After becoming infected with delta-series radioisotopes following an accident aboard coupled with the presence of a cloaked Romulan warbird nearby, had the effect of shifting Miles O'Brien forward in time by several hours on multiple occasions. O'Brien's return to the present altered the course of the future events that he witnessed, allowing him to change his own fate. On his final jump into the future, a controlled one to learn what would cause the destruction of the station, O'Brien became too sick to jump back to his present and he was instead replaced by the Miles O'Brien of three and a half hours into the future. ( DS9 : " Visionary ")

While on a trip to Earth to take Nog to Starfleet Academy, Quark , Rom , Nog, and Odo were accidentally propelled back to circa 1950, crashing near Roswell , New Mexico , due to a sabotaged warp core on a ship that had been given to them by Quark's cousin Gaila . They managed to return to their own time using the reaction between kemocite and the radiation of a nuclear explosion on Earth. These events – which included Quark attempting to alter the timeline by selling goods to the United States of America during the Cold War , and the Ferengi subsequently being interrogated on the suspicion that they were secretly planning an invasion – were kept secret from the public on Earth at the time. ( DS9 : " Little Green Men ")

Akorem Laan , a poet and seer from Bajor 's past (whom history had recorded had mysteriously disappeared) was sent to the future by the Prophets , believing he was the Emissary of the Prophets . Ultimately, Sisko convinced the Prophets to send Laan back into his own period. Laan later went on to finish one of his prophetic poems, which Major Kira remembered as unfinished, after Laan had disappeared. Sisko pointed out that the ending of the poem had appeared in databases, along with new history of his life after his return to Bajor. Although Kira wondered why she could remember the previous timeline if that timeline had been wiped out, Sisko commented that time worked in mysterious ways whenever the Prophets were involved. ( DS9 : " Accession ")

Quinn took the USS Voyager back in time to the Big Bang to hide from Q . ( VOY : " Death Wish ")

In 2373 , the USS Defiant , commanded by Captain Sisko, traveled back in time to 2268 via the Bajoran Orb of Time , in an attempt by Arne Darvin to kill James T. Kirk and change the timeline. The crew of the Defiant stopped Darvin without any notable damage. Major Kira found a way to use the Orb to get the Defiant and its crew back to their own time. ( DS9 : " Trials and Tribble-ations ")

In 2373, around Stardate 50814.2, the Defiant became stuck behind a barrier on a planet in the Gamma Quadrant , where the ship's crew met inhabitants of the planet, who told them they were actually descendants of the Defiant crewmembers themselves and that, in two days, the crew would be sent two hundred years into the past and crash on the planet. With foreknowledge of the crash, the crew surmised that, if they escaped that fate, the timeline would collapse and everything on the planet would cease to exist. A descendant of Jadzia Dax, Yedrin , surmised that it would be possible to save their colony, due to an energy discharge that had hit Major Kira, which had created a subspace doubling effect and, for an instant, created corresponding quantum duplicates of every molecule in her body. By amplifying the doubling effect through modifications to the Defiant , they could make a quantum duplicate of the entire ship, and this second ship would then be the one that would crash on the planet, preserving the original timeline. However, the other Defiant would be able to escape as well. Yedrin, though, had falsified information in his plan, with the intent of making sure that the original (un-duplicated) single Defiant would crash on the planet, thus ensuring that the colony would continue to exist. The Defiant crewmembers ultimately made the decision to sacrifice their ship by flying into the temporal anomaly, in order to save the eight thousand colony members. However, the ship's flight plan was changed, by a version of Odo who lived on the colony, so that it would clear the barrier, the future Odo wanting to save Kira's life. This erased the settlement and all of its inhabitants from the planet. ( DS9 : " Children of Time ")

Kira used the Orb of Time to learn about her mother's life on Terok Nor. Before she began her Orb experience, she was warned not to interfere with the timeline by Sisko. Kira nearly assassinated her own mother and Dukat , but changed her mind at the last moment. The Orb then returned her to the present. ( DS9 : " Wrongs Darker Than Death or Night ")

During a visit to the planet Golana with her family, Molly O'Brien was accidentally sent three hundred years into the past via a time portal created by a long-lost civilization that had once inhabited the planet. She was retrieved by her parents, but was now a teenager reduced to a feral mindset , forcing them to use the portal to send her back. However, their subsequent use of the portal sent the teenage Molly back to shortly after her past self arrived in the past in the first place, allowing her to send her past self back to the present. Shortly after saving the younger Molly, the older Molly ceased to exist, vanishing from existence as the timeline corrected itself. ( DS9 : " Time's Orphan ")

Also in 2373, an encounter with the 29th century timeship Aeon threw Voyager back to 1996 , while the Aeon crash-landed in 1967 and was discovered by Henry Starling , who used its future technology to make himself rich. History was corrected when Captain Janeway destroyed the timeship before it could travel to the future and accidentally cause a temporal explosion . Voyager was returned to the correct time by an alternate version of the Aeon from the correct timeline. ( VOY : " Future's End ", " Future's End, Part II ")

An alternate future version of Janeway (from 2404 ) traveled back to 2378 through the use of a chrono deflector , to bring Voyager home from the Delta Quadrant sixteen years earlier than it had arrived in that alternate future. This future Janeway was killed in the attempt but succeeded in returning Voyager home and even delivered a crippling if not fatal blow to the Borg . ( VOY : " Endgame ")

In 2381 , Ensign Brad Boimler was accidentally sent back to 2259 by the Krulmuth-B portal on Krulmuth-B when fellow ensign Sam Rutherford accidentally activated it with his camera , putting him in the care of Captain Pike and his crew of the Enterprise . Their attempts to return Boimler to the future were complicated by various incidents, including Beckett Mariner throwing herself through the portal, Orion scientists stealing the portal and the need to find a source of horonium to power the portal. ( SNW : " Those Old Scientists ")

In 2387 , Nero and Spock were sent back in time through a red matter black hole which had prevented a supernova from destroying the galaxy (but not before it had destroyed Romulus in the process). Nero was sent back to the past to 2233 , inadvertently creating a new spacetime continuum where he destroyed the USS Kelvin . He and his crew then went into hiding for twenty-five years, awaiting Spock's arrival. Spock arrived in Nero's new timeline in 2258 . Nero destroyed Vulcan , while Spock watched from Delta Vega . The crew of the USS Enterprise , with the help of James T. Kirk , stopped Nero from destroying Earth . ( Star Trek )

In 2401 , Q transported Picard, Elnor , Seven of Nine , Agnes Jurati , Cristóbal Rios and Raffaela Musiker into an alternate timeline where Earth was now the Confederation of Earth ( PIC : " The Star Gazer ", " Penance ") due to Q's own meddling in the past. With the help of an alternate Borg Queen , the group used the slingshot effect to travel back in time to 2024 in order to right history. ( PIC : " Assimilation ") Q later returned the group, minus Rios and Jurati, to 2401 using his own powers at the cost of Q's life due to his weakened state. The group was returned to just moments before they had left, giving them the opportunity to alter their own future slightly. ( PIC : " Farewell ")

Temporal Cold War and temporal wars [ ]

The events of the Temporal Cold War further complicated the understanding of Federation time travel capabilities.

As of the 28th century , a time-traveling faction, represented by a mysterious individual , could only communicate and exchange information and technologies through time, appearing as non-corporeal entities. By the 29th century , this technology was perfected to allow physical travel.

According to a Temporal Enforcement Agent from the 31st century named "Daniels", all time travelers were bound by the observance of strict procedures set forth in the Temporal Accords . Daniels stated that the Temporal Accords were enacted after time travel was developed by all time-travel-capable species to prevent catastrophic tampering with the timeline .

In 2153 , the Sphere-Builders , a group previously thought to possess the ability only to examine alternate timelines, sent Xindi-Reptilians back to 21st-century Detroit to develop a bio-weapon to destroy the Human race. ( ENT : " Carpenter Street ")

Ultimately, the war ended when the Na'kuhl returned from an alternate 1944 (created by their very actions) and caused the Cold War to become a war with time travelers changing time as they liked. Daniels brought Enterprise and Archer back to 1944 to stop Vosk , leader of the Na'kuhl, from returning to the future. With the help of Silik , a member of another faction of the Temporal Cold War, Archer shut off Vosk's compound 's shields , allowing Enterprise to destroy it and thus destroying the temporal conduit and killing Vosk, just as he was about to travel back to the future. Daniels pulled Archer to a place where they watched the time stream , as all of the events that had occurred while the Temporal War had been ongoing were undone and time reset itself to normal. Archer refused to have anything more to do with Daniels' "damn Temporal Cold War" and Daniels agreed, claiming it was finally coming to an end thanks to Archer's actions. ( ENT : " Storm Front ", " Storm Front, Part II ")

After the temporal wars, time travel was banned, and its technology destroyed. ( DIS : " That Hope Is You, Part 1 ")

In 3189 , after Philippa Georgiou started to die from being separated from her own time and the mirror universe for so long, the crew of the temporarly-displaced USS Discovery sought help from a being who turned out to be the embodiment of the Guardian of Forever . After testing Georgiou and Michael Burnham , the Guardian of Forever sent Georgiou back to a time when the two universes were still aligned and thus she could survive. ( DIS : " Terra Firma, Part 1 ", " Terra Firma, Part 2 ")

Opinions on time travel [ ]

Neelix believed that food could be like time travel; in his own words, " You inhale an aroma , take a bite of something and suddenly, bam! You're back at the moment you first tasted it. " ( VOY : " Workforce ")

When Captain Jonathan Archer saw an old clipper ship on an ocean on the Akaali homeworld , he noted that it was almost like "traveling back in time." ( ENT : " Civilization ")

Methods [ ]

• Black hole created by red matter
• Chrono deflector
• Orb of Time
• Q superpowers
• Red Angel suit using a time crystal
• Slingshot effect (Light-speed breakaway factor)
• Temporal causality loop
• Temporal conduit
• Temporal transporter
• Temporal vortex
• Time portal

Appendices [ ]

See also [ ].

• Department of Temporal Investigations
• Janeway Factor
• Temporal anomaly
• Temporal Integrity Commission
• Temporal Prime Directive

Background information [ ]

A list of episodes that feature time travel .

Apocrypha [ ]

In the novel Ishmael , Captain Spock embarked incognito aboard a Klingon ore transport , refitted with time travel capacity. The ore transport managed to go back to 1867 Earth after an acceleration close to a white dwarf near Starbase 12 . The USS Enterprise was modified to follow the ship to 1867, becoming the first instance that a Federation ship utilized intentional and controlled time travel.

In the video game Star Trek: The Next Generation - Future's Past for the Super Nintendo, the computer mentions several temporal near-catastrophes in the 23rd century : the New York incident, the above-mentioned "Ishmael incident", and the "Eyeglass Loop Paradox" referring to what Kirk does in Star Trek IV: The Voyage Home with his glasses.

The novel trilogy Star Trek: Deep Space Nine - Millennium features the Defiant inadvertently travelling twenty-five years into the future when they slingshot around a newly-formed red wormhole. Upon arriving in the future, Dax explains that time-travel leavers the travellers molecularly out of sync with the local time period in a manner that can only be averted if they either exactly repeat and reverse the process that sent them through time in the first place or if they travel in the opposite direction of their original trip by a considerably greater distance (in this case, it was suggested that the Defiant crew could travel back in time 25 000 years). It is left unclear what would happen if someone tried to go back in time via a different method- the use of the Orb of Time is suggested as one such method that could be used- but it is generally agreed that such an attempt either wouldn't work or prove unpleasantly fatal to the time traveller.

The Department of Temporal Investigations novels Watching the Clock and Forgotten History go into detail about the principles of time travel, as well as the hows and whys of the various time travel incidents in Star Trek 's history. The most significant of these demonstrates how Starfleet became aware that history could change – previously, the organization had assumed that changing history just created an alternate timeline that those who changed history happened to get 'stuck' in-; when the DTI created Timeship One with the intention of deliberately traveling three days into the future, a future version of the ship appeared in their time thirty-two hours before it was due to launch, the crew all dead or dying from an accident that had occurred when they overshot. With this discovery postponing the planned launch, the future Timeship One and its crew disappeared once the time of the original launch had passed, confirming that history could be changed.

External links [ ]

• Time travel at Memory Beta , the wiki for licensed Star Trek works
• Time travel at Wikipedia
• 1 Abdullah bin al-Hussein

'Star Trek: Voyager': The 7 Best Time Travel Episodes

“The future is the past, the past is the future, it all gives me a headache.”

The Star Trek franchise loves time travel. Some of the best episodes across the franchise’s many shows involve temporal hi-jinks, from heartbreaking episodes like “The City on the Edge of Forever” in the original series to hilarious ones like “Trials and Tribble-Ations” on Star Trek: Deep Space Nine .

20 years ago, Star Trek: Voyager came to an end with “Endgame”, a two-part finale that involved time travel. The Voyager crew were infamous for their temporal infractions, but at least they gave us plenty of great episodes to enjoy while breaking the temporal prime directive. In honor of the show’s swan song, here’s a look at the seven best time travel episodes on Star Trek: Voyager .

Season 1, Episode 3: “Time and Again”

The ship is hit by a shockwave and Kes ( Jennifer Lien ) believes she hears people crying out from a planet below. When an away team goes to investigate, Captain Janeway ( Kate Mulgrew ) and Tom Paris ( Robert Duncan McNeill ) find themselves trapped in the planet’s past. As if that’s not bad enough, the clock is quickly ticking down to a planet-wide catastrophe.

“Time and Again” is only the third episode of Star Trek: Voyager , but it handles multiple issues deftly. While we’re invested in Captain Janeway and Tom’s retrieval, the planet’s politics are equally riveting, especially the conversation about the episode’s version of nuclear power. It’s also a great character study—Tom Paris begins the episode apathetic to the planet’s residents since there’s no way to save them, but along the way, he changes his mind.

Season 3, Episode 8-9: “Future’s End: Parts 1 & 2”

Voyager is attacked by a ship from the future and is accidentally sucked into the 20th century. The crew have to juggle numerous missions—find a way to return their ship to its time, stop an evil tech mogul from messing up the timeline, and save a young scientist from said mogul’s goons. Oh, and the Doctor ( Robert Picardo ) needs rescuing, as well.

This two-parter feels like a quintessential 90s film. There’s a little bit of everything in it, action, comedy and famous guest stars . The episodes add to Star Trek lore, while also taking the crew out of their regular Delta Quadrant setting. Given that they’re on Earth during “Future’s End”, the characters also have to contend with the philosophical question of whether to stay on Earth, even if it’s not their Earth.

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Season 5, Episode 6: “Timeless”

A shuttlecraft lands on an icy planet and beneath the frozen surface is the familiar bow of Voyager. It’s the future and there are only two surviving members of the crew—Harry Kim ( Garrett Wang ) and Chakotay ( Robert Beltran ). Decades ago, Voyager thought they’d made a breakthrough to return home early, but instead, they’d met their doom. Now, Harry and Chakotay have the ability to save their friends. If they only had enough time.

“Timeless” is heartbreaking. Every time I watch it (and I’ve seen it several times), I can sympathize with Harry’s pain and guilt. It’s a layered episode that combines science-fiction elements with character development. The tension is heightened to the maximum. You’re genuinely left wondering if you’ll ever see the crew again.

Season 5, Episode 23: “Relativity”

“Relativity” begins on Captain Janeway’s first day aboard Voyager, but something’s not right. An ensign is snooping around the ship and to our surprise it’s none other than Seven of Nine ( Jeri Ryan ). How is it possible when Seven didn’t even join the crew until years later? Turns out, Seven has been recruited by the temporal ship, Relativity, as part of a secret mission to locate a device that will destroy Voyager. But time is not on her side.

“Relativity” is part time travel heist and part Groundhog Day . Not only is the ship at stake, but so is Seven’s life. This episode is fun and entertaining and ties in with numerous past episodes of the show. There are so many twists and turns that you’ll be at the edge of your seat.

Season 6, Episode 12: “Blink of an Eye”

Voyager gets trapped in a planet’s orbit and accidentally influences its entire history. Unbeknownst to the crew, time moves at a different pace on the planet—in the blink of an eye, entire generations are born, grow old and die, all while looking up to the “sky ship”. We watch as the planet’s residents worship Voyager, then begin investigating what it is, before finally attempting to reach it. Voyager couldn’t avoid changing the planet’s mythology, but they will do everything they can to save it.

“Blink of an Eye” is classic science-fiction, but its wistful and almost tragic nature make it a memorable entry in the canon. The episode writers chart a planet’s evolution, echoing humanity’s own history and understanding of the universe around us. That final scene of Daniel Dae Kim ’s character looking up at a departing Voyager will always make you tear up.

Season 7, Episode 10: “Shattered”

Chakotay is blasted by a shockwave and wakes up to an unrecognizable Voyager. The entire ship has been ‘shattered’ into different time periods, and Chakotay is the only one who can navigate through all of them. With friends and enemies all over the ship, how will Chakotay save the crew?

“Shattered” is a brilliant demonstration of how to use an old trope in a new way. Every time Chakotay enters a new timeline, you’re excited to see who’s there and how they’ll react to him. The episode builds a great deal of suspense along the way; you can’t guess how Chakotay is going to get the ship back together. And that denouement—it feels triumphant, but so emphatically in line with Star Trek ideology. “Shattered” takes place in the final season of the show, and the third act builds on everything we’ve learnt about these characters. The episode is compelling from start to finish.

Season 7, Episode 24: “Endgame”

“Endgame” begins with the celebration of Voyager’s 10th homecoming anniversary, but this is not a joyful time. The crew were stuck in the Delta Quadrant for over two decades, and they lost many of their friends along the way, while others have suffered a worse fate. This pain weighs heavily on Admiral Janeway and it’s no wonder that she is adamant to change her past to give her crew a better future.

This final chapter feels like an homage to the Star Trek: The Next Generation finale, “All Good Things ...”, which also employed time travel in its storytelling, yet “Endgame” carves its own path. There’s a lot at stake here, not just the crew’s return home, but the possible end to the constant threat of Borg invasion. The start of the episode is heartbreaking, especially as we learn more about the losses Voyager has suffered. This may not have been the most unique use of time travel, but “Endgame” certainly was a satisfying one.

KEEP READING: Quentin Tarantino's Star Trek Movie Would Have Involved Kirk and Time Travel, Writer Reveals

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Star trek: how time travel works in each tv show & movie.

From the original series to Discovery, Star Trek has never exactly been consistent with its time travel rules - here's how they (almost) work.

Time travel is possible in the  Star Trek universe — but its rules are inconsistent among the franchise's TV shows and movies. Time travel is a staple science-fiction trope, but it is also a problematic one. Although it is theoretically possible under Einstein's Theory of Relativity, it remains purely theoretical. As a result, every fictional franchise that deals with it tends to make up their own rules, figuring it out as they go along. In most cases, the pseudo-science of temporal mechanics comes second to plot necessity, and as a result there's usually a general degree of inconsistency. This isn't necessarily a bad thing; most viewers are willing (and able) to put the craziness of  Back to the Future behind them and enjoy the ride; movies are stories, not science lessons.

For all that's the case, though, the  Star Trek franchise is a little different. Gene Roddenberry intended this to be a hopeful and optimistic vision of the future, and as such he attempted to make his stories as consistent as possible. Naturally, the franchise as a whole has failed to achieve this; the more writers and showrunners that get involved, the more likely it is that the show's pseudo-scientific laws will start to contradict. The task was impossible, especially given how long the  Star Trek franchise has lasted.

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Still, that doesn't mean it's impossible to try to figure out the rules of time travel in the  Star Trek universe. Let's take a look at how it develops across the decades.

Time Travel in Star Trek: The Original Series

In the  Star Trek: Deep Space Nine episode "Trials of Tribble-ations," representatives of Starfleet's Agency of Temporal Investigations described James Kirk as an absolute menace. " Seventeen separate temporal violations, " one of their agents observed. " The biggest file on record. " It's difficult to say what exactly constitutes a "violation" in their terms, but one thing seems for certain; only a fraction of Captain Kirk's time travel exploits have been revealed, in the episodes "The Naked Time," "Tomorrow is Yesterday," "The City on the Edge of Forever," "Assignment: Earth," "All Our Yesterdays," and "Yesteryear." All were cases of traveling to the past, not to the future, which is presumably why they were considered violations.

" The City on the Edge of Forever " is one of the most fascinating time travel stories in the entire  Star Trek franchise. It saw the crew of the Enterprise discover a city filled with gateways to other times and other dimensions, and they inadvertently access one of these to change history. The crew in the city were protected from the effects, but otherwise all of creation was changed, and the Federation itself was erased. The model of temporal mechanics appears to be that there is just one timeline, and that is incredibly vulnerable to change; time travelers need to be incredibly careful not to change history. This generally fits with the other episodes, which see Kirk and his crew attempt to ensure they don't accidentally erase the Federation from history again. Sometimes their efforts are bizarre, and make absolutely no sense at all; in "Tomorrow is Yesterday," the Enterprise beams an Air Force pilot back into his fighter jet at the moment he was taking, which apparently has the side-effect of erasing his memories, for unclear reasons.

Time Travel in Star Trek IV: The Voyage Home

In  Star Trek IV: The Voyage Home , the Enterprise travels back in time to 1986 in order to save the Federation's future. This time, their explicit goal is to interfere; to reverse the extinction of humpback whales in Earth history by transporting them to their own time. Of course, this is a relatively minor change to the timeline, given the whales were about to be released into the open anyway and thus wouldn't be missed by anyone but their former handlers. In this case, history doesn't appear to be changed at all, although there is one questionable scene in which Scotty tells a scientist how to produce "transparent aluminum," but in the novelization he reflects he knew he was talking to the man supposed to invent it anyway. The crew of the Enterprise have apparently mastered the science of time travel to the extent Spock can precisely calculate how to ensure their ship arrives at the exact right moments in time.

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Time Travel in Star Trek: The Next Generation

Several episodes of  Star Trek: The Next Generation suggest a consistent universe, where the past is unalterable and unchangeable. This is most notable in "Time's Arrow," when the Enterprise is recalled to Earth when archaeologists discover the severed head of Data. Data insists his fate is sealed, because time cannot be changed, and thus the presence of his head means at some point he must travel back and face destruction. " At some future date, I will be transported back to 19th century Earth, where I will die, " Data insists. " It has occurred. It will occur."  He is soon proved right, but fortunately the ancient head is reattached to his body in the present. It's a basic time loop, a staple of science-fiction. Several other episodes suggest the same view of temporal mechanics. And yet,  Star Trek: The Next Generation isn't exactly consistent; it also suggests the creation of alternate timelines, most notably in the finale, "All Good Things..." There, Q transported Picard's consciousness through different timelines in order to ensure he had the knowledge he needed to save humanity. This hints towards the multiverse theory.

Time Travel in Star Trek: Generations

Star Trek: Generations makes an important contribution to time travel theory, in that James T. Kirk is essentially transported from his own time to the  Next Generation era by a temporal anomaly. This is significant, because it apparently confirms the existence of other dimensions where the laws of time do not operate in the same way. This, too, is a step towards the multiverse model in its broadest sense; not just the idea of other timelines, but of other planes of existence, where time is not quite so fixed.

Time Travel in Star Trek: First Contact

Star Trek: First Contact seems to return to the idea that time can be changed, with the Borg attempting to rewrite history and erase the Federation from existence. The crew of the Enterprise travel back as well, desperately attempting to ensure things stay roughly on course. They are successful, thankfully, and preserve their current timeline. This film is particularly interesting because it appears to suggest time has a certain resilience, one not seen in  Star Trek: The Original Series ; there are a number of changes, but they are absorbed into the timeline easily. Interestingly, Borg survivors emerge in the  Star Trek: Enterprise episode "Regeneration," and they send a signal to their brethren in the Delta Quadrant, creating a time loop where they had caused the Borg invasion in the first place.

Time Travel in Star Trek: Deep Space Nine

Star Trek: Deep Space Nine  had remarkably few time travel episodes, rather amusing given it features a wormhole - one of the few things theoretical physicists believe could allow time travel. One of the most fascinating episodes, "Past Tense," supports the theory of a single consistent timeline that is quite resilient to change; Ben Sisko is forced to take the place of a key figure in Earth history, and he ensures events play out as they should have. Afterwards, the only alteration to the timeline is a changing photo, incorporating his actions into the course of history.

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But this resilience only runs up to a certain point, as revealed in "Children of Time," when an entire colony established by the Defiant's crew due to time travel was erased from existence. And yet, again, this isn't consistent. "Accession" is a disturbing anomaly, because it sees the Prophets return Akorem Laan to his own time, but the crew of Deep Space Nine still clearly live in a timeline where that did not happen.  Star Trek: Deep Space Nine introduces the Orb of Time, which allows time travel; it is unclear whether this artifact, created by the Prophets, possessed special abilities that override the normal rules of time.

Time Travel in Star Trek: Voyager

Star Trek: Voyager 's temporal mechanics are no more consistent. The most famous episodes involving time travel are those involving glimpses of alternate timelines, with time travel used to avert disaster; this idea features prominently in the season finale "Endgame," in which a future Kathryn Janeway provides technology to ensure her younger self gets home quicker. Other episodes, however, hint more at a single consistent timeline that can be altered via time travel; in "Parallax" Voyager is lured into an anomaly by its own time-distorted distress call, while in "Year of Hell" a scientist called Annorax creates a device that erases objects from the timeline, with catastrophic effects as every past interaction is also changed. History is only corrected when the weapon is used to erase itself from existence, and everything previously affected is restored.

Time Travel in Star Trek: Enterprise

No  Star Trek TV series has yet been affected by time travel as much as  Star Trek: Enterprise , which featured a so-called "Temporal Cold War." This conflict was instigated by several rival time traveling factions who were each attempting to rewrite history in their own advantage, clearly indicating the existence of a single consistent universe where history can nevertheless be altered. This revealed the galaxy eventually agreed to the Temporal Accords, restricting the use of time travel, but that some rogue planets insisted on their right to improve their own past — even if it meant damaging the history of other worlds. "Storm Front Part I" and "Storm Front Part II" nevertheless revealed paradoxes cause damage to the fabric of time itself, unleashing devastating and destructive temporal anomalies. It is possible many of the temporal and spatial anomalies encountered in different  Star Trek TV series were created by the Temporal Cold War.

Time Travel in J.J. Abrams's Relaunch

J.J. Abrams'  Star Trek relaunch commits the franchise to the multiverse model of time travel, with the time traveling Nero creating a new branch in time referred to as the "Kelvin Timeline," because it was initiated by the destruction of the Federation starship Kelvin in 2233. This is easily the most significant development in temporal mechanics in the entire history of  Star Trek , because the franchise is now committed to exploring two timelines, not just one. It is unclear, however, whether writers have quite grasped the importance of this in terms of  Star Trek 's pseudo-science; as always, time travel appears to serve the purpose of the plot, a convenient excuse for relaunching the franchise on the big screen while continuing the previous stories on the small screen.

Time Travel in Star Trek: Discovery

That brings us, finally, to  Star Trek: Discovery  — another show that promises to be transformed by time travel. Season 2 introduced the Red Angel , a suit created by Section 31 in the 2030s because they feared a temporal arms race with the Klingons. The Red Angel used a time crystal and micro-wormholes to jump through time, but Gabrielle Burnham found herself stranded in a dystopian future where an AI called Control had destroyed all organic life in the galaxy. She subsequently traveled back in repeated attempts to rewrite history and avert this horrific timeline. In the end, Gabrielle's daughter Michael Burnham took the codes that would enable this galactic genocide to the 32nd century, along with the USS Discovery.

One of the more important contributions to time travel lore, however, was introduced in the  Star Trek: Discovery tie-in novel  Dead Endless . Unlike traditional  Star Trek tie-ins, these are considered canon, which makes  Dead Endless particularly interesting; it is set in a slightly different timeline to the normal one, in which Michael Burnham never mutinied and triggered the Klingon War. It reveals the mycelial network weaves across the entire multiverse, allowing travel through both time and space; it is roughly analogous to the Marvel Cinematic Universe's Quantum Realm. Discovery's spore drive is, consequently, the key to exploring the multiverse — but, ironically, it is never used in this way in the main timeline. There, experiments with the spore drive were disrupted by the Klingon War; when Discovery traveled to the 32nd century, it took the galaxy's one expert with it, and spore drive technology will have been discontinued. Still, this builds upon the idea of the multiverse, and even introduces the multiversal Federation  — a group who will presumably never be encountered in the normal timeline, due to the abandonment of the spore drive.

Looking at all these examples, it's difficult to establish a unified theory of time travel in the  Star Trek universe. The best attempt was conducted by Christopher L. Bennett in his book  Department of Temporal Investigations: Watching the Clock , but that isn't considered canon, and has already been contradicted. But, of course, this is how it should be; time travel is theoretical, and should only ever be treated as a plot device, not as a hard and fast rule that binds writers' hands.

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