Time travel in movies is nothing new, with movies such as “Back to the Future” and “Timecop” relying completely on the concept to forward their plots.
Since the technology to travel through time does not currently exist, there are many people out with theories on how time travel works, and many different movies that use different time travel mechanics to provide an interesting story.
So what’s the skinny on time travel? In all honesty, there are really only three different types of time travel that appears in the movies.
1. CHANGEABLE TIMELINE
In a changeable timeline, one has the ability to go back into the past and alter history so that the future reflects it. For example, if you go back in time and prevent your parents from meeting, you will cease to exist because you could never be born (essentially the plot to “Back to the Future”). Movies that feature a changeable timeline include “The Jacket,” “Timecop,” and “The Butterfly Effect.”
“The Butterfly Effect”
Not only is this a poor movie featuring Ashton Kutcher, it is also an exploratory journey into the theory that a butterfly flapping its wings in one part of the world can cause an eventual hurricane in another, albeit weeks later. In this movie, Kutcher is able to go back in time and change little things in the past, though they have largely unforeseen consequences when he travels back to the future.
Every time he goes back in time he rewrites his history and experiences the outcome in real time. Kind of trippy, a lot of danger, and one of the main reasons that protagonists traveling through time machines are always extremely wary of altering events in the past; a rogue sneeze could cause a pandemic that the world was never prepared for, a piece of trash could accelerate technology production — that type of thing.
2. UNCHANGEABLE TIMELINE
This is generally the most simplistic of the variety, hinging on the idea that if you go back in time to change the future, you will actually be a catalyst that contributes to the way the future was when you entered the time machine. One of the best examples of this type of timeline can be seen in James Cameron’s “The Terminator,” though with a very paradoxical catch.
The whole “Terminator” series is highly dependent on naked time travelers coming back from the future in a bid to alter history. In the first movie, Skynet sends a terminator from the year 2029 to 1984 to kill Sarah Connor so that she will be unable to give birth to John Connor, the key leader of the resistance in 2029. John Connor (the 2029 version) also sends somebody back in time to combat Skynet’s terminator, named Kyle Reese. Eventually, Kyle Reese hooks up with Sarah Connor and they defeat the terminator, though Reese gets wounded badly and dies.
Here’s where the paradox comes in; it turns out that before Kyle Reese died he impregnated Sarah Connor, who will father John Connor, who will eventually send Reese back in time. On top of that, a company called Cyberdine finds remnants of the destroyed terminator, and uses that technology to create what will later become Skynet and the terminators.
In this very complicated twist on the unchangeable timeline, not only can the past not be changed to alter the future, apparently time can operate on a very complex chicken-or-the-egg loop.
3. MULTIPLE TIMELINES (and universes)
This theory relies on a theory of quantum mechanics that posits the existence of multiple dimensions or universes. As soon as one goes back in time, they create an alternate dimension that another version of themselves may exist in as well. Essentially this means that killing your own father in an alternate dimension would not destroy the “you” that murdered him, but it would prevent you from being born in the universe that you entered. J.J. Abrams’ “Star Trek” (2009) displays this well.
“Star Trek” (2009)
In this film, the creation of the secondary universe is asserted at the very beginning of the movie, with a Federation ship coming under attack by a Romulan ship, seemingly from the future. It turns out the Romulan ship was from the future, having been sucked into a black hole and spit back out 50 years earlier.
When the ship reappeared 50 years before its own creation, it initiated a chain of events that would directly contradict the canonical happenings in the universe that all of the other “Star Trek” TV shows and movies inhabited — but it didn’t destroy the hearts of Trekkies across the world, because “Star Trek” (2009) exists within its own universe, and within its own timeline.