In this succulent, I try to decode the science behind Tenet, and how it could be possible in the real world, using the concept of a Mobius Strip.
*SPOILER ALERT*
The movie’s first actual line to progressing the plot is said by the scientist who meets our protagonist. While explaining how bullets go back into the gun, she says, “Don’t try to understand it, just feel it.” This line made me chuckle as I felt that that was exactly what the movie was trying to tell us all along. Even if we didn’t necessarily understand the concept, the movie wants the viewer to just sit back and enjoy the events unfold.
You can check out some videos here: https://www.sayalipatukale.com/post/tenet-videos
THE SCIENCE BEHIND TENET:
Tenet revolves around two scientific concepts:
Entropy
Time
Entropy: The state of the randomness of a system (molecular disorder) is called entropy. The more the randomness, the more the entropy.
As studied in my chemistry and physics classes, the value of the entropy of the universe is always absolute (i.e., Always positive). That is because, since the universe is always expanding, randomness (entropy) would constantly be increasing. However, negative entropy can exist in relative terms.
Negative Entropy: Comparing two systems (1 and 2) where 1 has a higher state of randomness (entropy) than 2, we can say that system 2 has negative entropy as compared to system 1.
For example, water turning into ice is a perfect example of negative entropy. Water (a liquid) has more space for the molecules to move, thus it has more randomness than ice (solid). In this scenario, the entropy of the system (H2O) is negative.
To determine whether an object has negative entropy or not, you have to compare it with a point in time (i.e., the value is relative).
In Tenet, we have a concept of ‘inverted entropy’ which the bullets seem to possess. Let’s check out whether it’s the same as negative entropy or not.
Inverted Entropy: From my understanding of the movie, the concept ‘inverted entropy’ has little to do with entropy and has much more to do with time itself. Here is where the concept of time weaves itself and creates a bit of confusion.
Inverted Entropy is not an actual scientific concept but is tailormade to fit the narrative of Tenet. It is Nolan’s brainchild. Theoretical physicist Kip Thorne had previously helped Nolan with Interstellar to make the film as scientifically accurate as possible. He helped with Tenet as well, but Nolan admitted that the film was only loosely based on science.
That being said, let's deal with inverted entropy. Imagine you put water in a freezer. After a certain amount of time, the water freezes to ice. What we observe is that water freezes to ice. But for a person viewing it from an inverted standpoint, they will see it in reverse, that is, the ice turning into water.
As seen in the diagram, at 7 am we can see 2 bowls (point of reference ‘what we see’). One full of ice and the other water.
To understand this better, let’s use the concept of a Mobius strip.
Mobius Strip:
The Mobius Strip in physics looks exactly like this yummy lemon peel. By definition, let’s say we were to walk from a point on the Mobius Strip. After a certain amount of time, we would have traversed the entire strip (on both sides) and will have arrived at the same point. Hence, this Mobius Strip has only one side.
This is about time travel. Assuming that space-time is like fabric, if we could bend it into a Mobius Strip, we could theoretically travel back into the same point in time.
Reference: https://www.youtube.com/watch?v=vLgCq4ikl78
(Amazing video by Neil deGrasse Tyson explaining the Mobius strip!)
Interesting to know, if we did live in such a world where our space-time was in the form of a Mobius Strip our right hand would become the left and vice versa, resulting in us being truly “inverted”.
This concept is the basis of a story by renowned scientist Jayant Narlikar. The sci-fi short story is available in his book, “The Return of Vaman”.
Since the Mobius Strip is in 2D the 3D equivalent of it would be the Klein Bottle. It has no inside, it has just the outside (one side).
Why are we using the Mobius Strip?
As I perceive it, it is a way through which it can be explained how the movie works. It also makes sense, that the protagonist created this organization (TENET) and trapped people in multiple Mobius strips to maintain balance through the universe.
I’m going to try and use the Mobius Strip to explain a completely different concept in Tenet.
Check out this figure. Here, we assume that normal time is linear and we move forward through it. It is a representation of a bowl of water kept in the refrigerator from 7 am to 8 am. Then the temperature is decreased allowing the ice to melt to form water again at 10 am.
Now, we fold this space-time strip in half so that the figure is like this on each side.
Now, we convert this strip into a Mobius Strip, by joining it with tape.
Let’s traverse this Mobius Strip with a red sketch pen. This is where the fun begins.
1. We start at the water at 7 am.
2. Then the water is cooled to form ice by 8 am.
3. As we traverse further, this is where the inversion takes place. According to us, we see that there is water in the bowl in the refrigerator at 10 am.
4. Going further, we see that that water has turned to ice at 9 am. Thus, we have traveled back in time to start again at the water at 7 am.
The inversion here is that, even though the ice was supposed to be melting from 9-10 am, we saw it freezing, because, for us, it happened backward.
It is important to note that as viewers now, we can see the Mobius Strip from a somewhat absolute reference point. However, if we were a part of the Mobius Strip, we would be “inside” the frame of reference and not mere observers. Hence, we would experience the freezing of the ice when heat is applied.
By using this model of explanation, we can make the following deduction:
To travel back in time on the Mobius Strip, the event must have already happened in linear time.
Order of events:
Event: Freezing the ice. Melting the ice.
Creating a time loop of the event (i.e., a Mobius Strip environment).
Traveling through the Mobius Strip as a mere observer.
This clearly explains the inverted plane scene. The first time we saw the fire, we saw a man coming from the turnstile wearing a suit who battled the Protagonist and in the very end, Neil stopped the Protagonist from killing the man. The second time we see the scene further in the movie, we see that the man in the suit is the Protagonist himself. The end of the scene was the beginning for him now as he was greeted with his past self-trying to kill himself. The end of this scene was the beginning for the past Protagonist as he saw the man in the turnstile.
Finally, let’s take a look at the path the bullet in Tenet will have to travel through the Mobius Strip.
If this linear strip is made into a Mobius Strip, the bullet traversing this path will be stuck in the following INFINITE loop:
---> 1. GUN----> 2. TARGET--->3. GUN----> 4. TARGET---> 5. GUN---->
The Scientist’s conversation at the beginning of the movie talks about cause and effect with the protagonist. In this scenario of the “inverted bullet”, a probable way to explain the phenomena would be that the bullet was shot once from the gun into the target. Then this particular action of the bullet was converted into a Mobius Strip. Since according to us, the bullet is inside the target (step number 2), the bullet would then move to step number 3 which is the gun again. This action will continue repeatedly.
Based on the concept of the Mobius Strip, I believe the concept of Tenet can be explained by linking a combination of these strips to fit the plot of the movie.
If you notice closely, throughout the movie, you see 2 parallel timelines happening together, where one cannot exist without the other. Examples of such scenes are:
The Opera House, where Neil was the one who saved the Protagonist. Where we saw the inverted bullet for the first time.
The inverted plane crash.
The turnstile and the inverted car chase.
Kat seeing herself jump off the yacht.
The conclusion where Neil has to go open the door again.
All of these scenes in the movie, lead to only one conclusion in my opinion… that they are all stuck in an endless loop that the Protagonist has created. If you notice, none of the actions the protagonist takes are changed in any way as the story progresses. For example, the inverted car chase, where he sees himself in the car, and the plane crash where he fights with himself.
The amalgamation of this concept happens at the very end during the last conversation that Neil and the Protagonist have.
Protagonist: But, can we change things if we do it differently?
Neil: “What’s happened happened”. Which is an expression of faith in the mechanics of the world. It’s not an excuse to do nothing.
Protagonist: Fate?
Neil: Call it what you want.
Protagonist: What do you call it?
Neil: Reality.
This concept is explained in two different ways by scientists today, and it’s called the Grandfather Paradox.
Grandfather’s Paradox:
Imagine you travel back in time to kill your grandfather. The problem here would be that, if you kill him, logically, you wouldn’t be born and as a result wouldn’t be coming back through the time machine to kill your grandfather. This creates a contradiction called the grandfather’s paradox.
However, some scientists believe that it is very much possible to go back in time and kill your grandfather. The way this would work is that, when you go back in time, some of the other incidents, or call it coincidence if you like, would take place, resulting in you not being able to kill your grandfather. Or, if you do manage to kill him, your father/mother would have already been born, and thus you would exist.
A couple of scenes in the movie, do hint at this theory.
In the scene just before the inverted plane crash (the second time) the Protagonist and Kat have a conversation with Neil where Neil explains to them what the algorithm is.
Neil: The algorithm can invert the entropy of the world. Everyone and everything that’s ever lived will be destroyed instantly.
Protagonist: I’ve been thinking, we’re their ancestors. If they destroy us, won’t that destroy them?
Neil: This brings us to the grandfather’s paradox. If you went back in time and killed your grandfather, how could you have been born to commit the act?
Protagonist: What’s the answer?
Neil: There’s no answer. It’s a paradox. But in the future, those in power believe that you can kick grandpa down the stairs, gouge his eyes out, slit his throat, without consequence.
Protagonist: Could they be right?
Neil: Doesn’t matter. They believe it. So, they’re willing to destroy us. Can I go back to sleep now?
Protagonist: No. I thought of something else. This reversing the flow of time. Doesn’t we being here now means it never happens? That we stop them?
Neil: Optimistically, I’d say that’s right.
Protagonist: Pessimistically?
Neil: In a parallel worlds theory we can’t know the difference between consciousness and multiple realities.
This can show us that all of the events in the movie cannot exist on their own, they are interconnected. “What’s happened happened” simply means that today if we were to go back in time to kill a leader, the World Wars would still happen. Similarly, in the movie, the events do not change, we are just shown different sides of it.
So why won’t the past change even though we try to change it?
In my theory, when we travel back to the past, we are not mere observers, we become a part of the past as well. Hence, whatever we try to do, the outcome might be the same to maintain a balance in the universe and space-time. It simply does not matter what changes we make. They just have to remain constant.
Dimensions:
Imagine a sphere in 3D. What would it look like in 2D? A circle. What would it look like in 1D? It would be a line. If we tell the line that its reality is a sphere, no matter how hard the point tries, it will never be able to imagine what a sphere is like because its understanding is only limited to 1 dimension.
In the same way, we humans are 3D figures. Imagining higher dimensions is beyond our capacity. However, due to the research conducted by some scientists, time can be imagined as a 4th dimension to some extent.
That’s probably why our scientist Laura says “Don’t try to understand it, just feel it.”
Examples of Mobius Strips in TENET:
First let’s go through the main events in the movie, excluding the temporal pincer.
Kate took her last trip with her husband Sator on that cruise. She saw that girl jump off the boat.
The plane crash was deliberately done to the warehouse. The protagonist and Neil, battle the people from the turnstile.
The car sequence where they rob the piece of the algorithm. Where the protagonist sees an inverted car driving.
The protagonist goes back into the turnstile and becomes the driver driving the inverted car. He sees himself too.
He realizes this was not helpful and decides to go back to the plane crash. He goes into the warehouse and fights with himself and Neil.
Finally, Kat is given the task of distracting Sator till the temporal pincer is over. She jumps off the boat and realizes that she was that girl all along.
Normal space-time is linear and one-dimensional. We only go forward. It is like a line. That is how we exist. Now, if we want to represent this linearly… this is how it would look like:
However, the way the protagonist has designed this for his organization TENET is a bit more intricate.
We can see that when event 1 was happening 6 was taking place too. Similarly, when 2,3 were taking place, 5 and 4 were there respectively.
Thus, we can create a Mobius strip!
STEP 1:
The protagonist has managed to create 2 copies of events and combined them like this in space-time.
This theory fits because there are 2 copies of Kat, and the protagonist wherever required.
STEP 2:
Bend this spacetime to form a Mobius strip. A Mobius strip has only one rotation, as we’ve seen while making it.
Here, we get 2 pathways.
Hence, a person on the blue pathway is not the same as the one on the red pathway. This will also make sense as none of the characters had any memory of themselves in the beginning instances when they saw themselves.
So, the red pathway moves from 1-6 and back to 1. The blue moves in the same way. Both colors remain separate.
Take a look at TENET’s logo.
Now, if 1,2,3 are the original sequences, then the ‘net’ part is an inverted sequence. Quite similar to our real sequence cases:
This is the normal case scenario.
However, if we rotate the blue text by 180 degrees (ie. Invert it) this is what we get:
Which is exactly the sequence we planted on our Mobius strip.
The word TENET can be a reminder of the formula of inversion to the protagonist.
It’s all pretty symbolic, but the sequences are somewhat based off on the gist of this logic.
The Protagonist made the organization as well as these loops/Mobius strips. At the same time, nothing changes, because the protagonist when inverted arrives in the same car crash position, no matter what Kat does, she still sees herself jumping off the yacht.
Hence, the crux of the movie is that, no matter how much the characters try, they cannot change anything. The whole point is to go through the process to keep things the way they are.
Some of the concepts were confusing. Let’s see what they are:
Turnstile
Temporal Pincer
Third World War (from the future)
TURNSTILE:
The turnstile is simply a device to invert a human being and help them go back through time, as they perceive it. Inversion means, instead of going forward in time, you’ll move backward and perform some tasks.
TEMPORAL PINCER:
It's a strategy developed in which people going forward through time communicate with people going backward. In such a case, they cover all possibilities of attack and it will help them win in the end.
THIRD WORLD WAR:
The third world war is between the past world (present movie) and the future. The future world is messed up and they want to undo everything in the past. TENET is an organization that the protagonist created to destroy the algorithm and helps stop what is happening.
TENET helps us realize that traveling through time may not change the outcome of the future. Because when travel through time, we are not observers. We are a part of the system.
That’s why, “what’s happened, happened” becomes the crux of the movie and our life.
"We are not observers, we are part of the system."