Time travel is one of the pillars of the Terminator series, but the rules of going back in time are not quite easy to understand, given the number of retcons that have happened throughout the franchise. While James Cameron’s The Terminator was not defined by its time travel element, we cannot deny that time machines and alternate timelines are part of the franchise’s DNA. A large portion of Terminator’s lore is built on time travel, including a couple of intentional paradoxes that would forever affect the franchise and its most important heroes.

Like the Terminator films have stuck to a somewhat consistent set of rules for the most part.

Time Travel In Terminator Is Done Through The Time Displacement Equipment

The Time Machine In Terminator Is Often Portrayed As Three Giant Rings

Although there are some exceptions to this, time travel in Terminator can only be done through the Time Displacement Equipment. Described as a time weapon, the TDE was presumably created by Skynet and is usually depicted as a major device formed by three rings that accelerate an incredible speed before opening a portal to another time. The Time Displacement Equipment is always hidden in a large facility, usually controlled by Skynet. Interestingly, there is no confirmation in any of the Terminator movies about who created the first TDE, humans or Skynet.

The time travel process is not always accurate, meaning the subject can accidentally be sent to the wrong time or location.

We can assume that Skynet was the one who started this “time war,” but the fact is that only the original script for The Terminator and the novelization for Terminator 2: Judgment Day actually state that the machines were the ones who discovered time travel. It is also worth noting that, according to Terminator 2, Skynet’s very existence is a time loop since its creation was based on the technology of the T-800’s hand that was left in the 1980s. Considering that Skynet created the first time machine, the creation of time travel in Terminator is a paradox.

Terminator: Rise of the Machines establishes that, in this timeline (the one created after the events of Terminator 2 postponed Judgment Day), there are two-time machines. Both Skynet and the Resistance have access to a time device, which is known as the Continuum Transporter in this version of the story. Other time travel devices in Terminator include the Time Door, which, in Terminator Salvation, is used to send data to the past instead of machines or living beings. The time travel process is not always accurate, meaning the subject can accidentally be sent to the wrong time or location.

Only Things Surrounded By Living Tissue Can Be Transported By The TDE (Supposedly)

Terminator’s Most Famous Rule Is Not As Simple As It Seems

Perhaps the most famous yet misunderstood time travel rule in Terminator refers to what can actually be transported by the Time Displacement Equipment. For something to be sent back in time through the TDE, it must be surrounded by living tissue. While there might be an exception to this rule regarding the T-1000, the fact is that involving a machine in living tissue is supposedly the only way to send a Terminator back in time. What causes so much confusion about this rule is that, in The Terminator, Kyle Reese says only living things can be sent back in time.

While a Terminator head (without the living tissue) was shown to have been sent back in time in Terminator: The Sarah Connor Chronicles, its living tissue was presumably destroyed right before the process was completed.

Although the Terminator franchise is full of retcons, we can assume that Kyle Reese either did not express himself correctly or did not fully understand how the Time Displacement Equipment worked. The idea that Terminators must be covered in living tissue rose as the best explanation for why the T-800 could be sent back despite what Kyle Reese said about the time machine. The living tissue rule also explains why humans and Terminators must be naked while using the time machine. Whether other objects such as weapons can also be covered in living tissue and sent back is unclear.

Going Back In Time Does Not Change Your Future In Terminator

Terminator (Mostly) Adheres To The Existence Of Multiple Timelines

A recent addition to the Terminator lore, Terminator Zero established what is likely the most important rule regarding the franchise’s time travel – going back in time does not change your future. Instead, it creates a new timeline. While previous Terminator movies and The Sarah Connor Chronicles had tackled alternate timelines before, Terminator Zero made it clear that every change to the past creates a new reality. In other words, every time Skynet and the Resistance use time travel, they are creating infinite new branches. The existence of infinite timelines solves a lot of plot holes in Terminator.

Terminator Zero does not feature Sarah or John Connor.

Terminator Zero confirmed that going back in time creates a new timeline, particularly to highlight how pointless the “time war” fought between humans and Skynet had been. While the series did not mention John Connor, it talked about how leaders would rise, achieve a major victory, and prompt the machines to use time travel, which would restart the cycle. The “multiple timelines” explanation is usually the best way to explain any time travel story, and it can hardly be contradicted by any of the Terminator movies since it establishes the existence of infinite realities.

This also adds to the idea that the war is never over in Terminator. Assuming the existence of infinite timelines, there is an infinite number of realities in which Skynet and humanity are still at war, which is why both Terminators and human agents keep showing up in the present day. Not every Terminator property has stuck to this explanation, but it is the one that best explains how time travel affects the timeline in the franchise.

Every Time Terminator Changed Its Time Travel Rules

Terminator Has Bent Its Own Rules A Few Times

The Terminator’s biggest plot twist was intentionally paradoxical, but it ended up raising some questions about that universe’s time travel rules. The fact that Kyle Reese was John Connor’s father suggested that the future was already written and that everything was happening within a closed loop. However, in Terminator 2: Judgment Day, we are asked to believe that the future has not been written yet, and that humanity can save itself. Terminator 2’s message is that it is never too late to change the future, but Terminator 3 established that Judgment Day cannot be prevented, only postponed.

Another instance in which Terminator broke its rules, or at least made them more complicated, is when the T-1000 was sent back. Unlike the T-800, the T-1000 was not covered in living tissue as far as we know it. Its “human skin” was actually a mimetic polyalloy, which is what made it a shapeshifter. This suggests that, in addition to living tissue, time machines in Terminator can also transport mimetic polyalloy, adding an important exception to the famous rule.

Terminator's Time Travel Rules Compared To Other Similar Movies

From Back To The Future To The MCU To Looper

Terminator was not the first movie franchise to tackle time travel and there have certainly been plenty of others that have followed since. However, as one of the most iconic takes on the concept in pop culture, it is interesting to see how other films have been similar and different from Terminator's time travel ideas.

Another '80s franchise that gives Terminator a run for its money in of time travel fun is the Back to the Future franchise. It deals with the idea in a much more humorous way, as evidenced by the fact that the time-travel machine is made out of a DeLorean. However, when that DeLorean reaches its necessary 88 miles per hour, the lightning and vortex effects do resemble the Terminator time travel a bit. However, while the Terminator movies insist the past can't be changed, the Back to the Future movies have hijinks based on the problems of accidentally changing the past.

Time travel was brought into the MCU in a big way in Avengers: Endgame as the remaining heroes sought to undo Thanos' snap by going back in time, reassembling the Infinity Gauntlet, and using it to bring back everyone who was lost. Its superhero logic uses the quantum realm as an avenue to reach the past with the idea being that, while they might change the past initially, they can then return to bring the stones back to where they found them in history and set things back on the right track.

It deals with the idea of the future being inevitable, such as in the Terminator movies.

However, perhaps the movie that most resembles Terminator in of time travel is Rian Johnson's Looper. The filmmaker was clearly inspired by James Cameron's work, creating a story in which time-travel is used by criminal outfits to dispose of people by sending them to the past. It deals with the idea of the future being inevitable, such as in the Terminator movies, as Bruce Willis plays a man who travels back in time to kill a young boy who will eventually become a vicious mobster, only to realize his actions are what create the villain in the first place.