Written By Sneha Senthilkumar (Grade 11)
What is reality? We believe that the universe we exist in now, including the galaxies, stars, planets, is our reality and there isn’t more to it. There is only one reality, and that is the one that we all live in. That’s the preconceived assumption, right?
The 2018 Academy Award Movie ‘Spiderman: Into the Spider-verse’ explores a scenario where there are parallel realities, through which Spider-Man meets alternate versions of himself after an accident at a particle collider. This whole concept must sound like a fantasy to you, just the regular twist made by the director to make the movie interesting and conceptual.
But, what if I told you that there actually are multiple realities, that exist simultaneously? That they had universes similar to ours, and environments similar to the ones we are familiar with?
What if I told you, that there was truly another version of you living in an alternate reality. For all we know, what if that other ‘you’ is reading this article right now?
I’m sure most of you are puzzling over the previous sentence. How is that even possible? How can there be another ‘me’ when we are all supposed to be ‘unique’? It sounds very possible in a fictional movie, but how can there be anything like that in real life? Was Spider-Verse hinting at a possible multiverse affecting our everyday lives, and we know nothing about it?
If we want to apply this to the world we live in now, we are going to have to get into the science behind the multiverse, with a pinch of philosophy too. If you are up for the challenge, and if you are curious to know more, go on and read ahead.
Let’s start off with the basics. Physics is divided into classical physics and quantum physics. Classical physics is basically the branch of physics that explains most of the events we see in our everyday lives, like the trajectory of a ball or the rotation of planets. All of these things are easy to comprehend, as we are used to the classical physics aspect of the world. On the other hand, quantum physics deals with more bizarre phenomenon. Like really, really bizarre.
Both classical and quantum systems evolve in a deterministic manner, and you can predict how that system will behave if you apply the respective equations with the initial conditions. The behavior and evolution of a system in classical mechanics is more graceful, it follows the equations describing it easily.
A quantum system, like an electron has a wave function. The wave-function is quite the joker, because when you are not looking at it, it obeys an equation known as the Schrödinger wave equation, using which we can predict how the wave-function will evolve as time passes. The catch is that, there is a whole different set of rules when you look at it. When you observe the quantum system, the wave function collapses to a single point in space. This is known as the measurement problem. This concept will make more sense when I explain superposition, but just keep it in mind anyways.
The other two phenomena that make up an important part of the multiverse theory are superposition and entanglement. Superposition, as you already know, occurs when a quantum system exists in two states at the same time. Simple.
Entanglement is when two particles interact physically, resulting in both particles to be described by the same wave function. This essentially means that action performed on one particle affects the other. So, measuring one of them affects the state of the other and that single wave function, describing both particles, collapses.
All right, now you pretty much know the basics. Now it’s time to put together the pieces of the puzzle. And to do that, we will be using an infamous thought experiment known as Schrödinger’s cat to understand how there can be multiple realities on a small scale. Schrödinger’s cat was a though experiment proposed by physicist Erwin Schrödinger, to show just how weird quantum mechanics, and also more importantly, to show the possibility of the Many-Worlds Theory.
The scenario is this – there is a closed box containing a radioactive atom, a radiation detector, and bottle of poison and amidst this, a cat is placed in the box too. If the radioactive atom does decay, the detector will detect the radiation causing the poison to be released, and so the cat dies (morbid thought I agree). But, if the atom does not decay, detector won’t detect radiation, so the poison won’t be released, meaning that the cat stays alive. We don’t know whether the atom is going to decay or not decay, so we say that the atom is in a superposition of decayed and not decayed. The state of the radiation detector (detected or not detected radiation) and the state of the cat (dead or alive) is directly tied to the state of the atom. Basically the fate of the cat is directly tied to the state of the radiation detector, which in turn depends on the state of the radioactive atom. As established before, since the radioactive atom is in superposition, it will result in the radiation detector and the cat being in superposition as well. So the whole system inside that box is in a quantum superposition and is described by a wave function. Only when you open the box, making a measurement, the wave-function collapses (meaning there is no superposition anymore) and the cat is either dead or alive.
This way of looking at the situation is known as the ‘Copenhagen Interpretation’, which says when there is a superposition, and you look at it, the wave-function collapses and you only see one of the two possibilities that were in superposition. The End.
But the Many-World Interpretation (MWI), arises from this measurement problem – where did the other possibility go? In retaliation to the Copenhagen Interpretation, MWI states two points.
- Firstly, you as a human are made of atoms, and atoms are made of other quantum particles. Therefore, you yourself are a quantum system, so you would definitely obey the laws of quantum mechanics, meaning that you, just like the cat, could undergo superposition. Then why would you treat yourself as a classical system when you are making a measurement? Strong point, right?
- Secondly, for a second, I want you, to forget that you are a person with a conscience. Just picture yourself as a physical system obeying quantum physics and other physical laws. The moment you open the box and look at the cat, no measurement is made and we just ‘interact’ with the system and get entangled with the state of everything inside the box. This means we would also be in a superposition, and we see the cat both alive and dead, but the version of you that saw it alive, and the version of you that saw it dead inhabit two different worlds, and those two copies of you exist in their own realities and never interact. I will briefly explain how this is possible.
If a quantum object in superposition gets entangled with the environment, which consists of air molecules and photons (quantum version of the ‘environment’), it is said to undergo environmental decoherence, causing the wave function to branch. So in the case of Schrödinger’s cat, the detector becomes entangled with the superposition of the atom, but the detector is being bombarded by air molecules and photons, which would bounce off differently if there were radiation. This means that the detector has got entangled with the environment’s state (due to this interaction), causing decoherence and thus the wave function to branch. So the moment, you open the box, two copies of you are created in different worlds.
This means that the wave function is branching all around us, and every outcome happens 100% of the time, but we don’t experience that because our reality is just a sliver of a huge multiverse. You just need to keep in mind that this only happens if there is environmental decoherence.
Now that you have understood the science behind the Many-World Interpretation, and the conditions for parallel realities to exist, let’s look at the ‘Spider-Man interpretation’ of the multiverse. This is my analysis of the movie based on my knowledge, so I might not be 100% correct.
- So in the movie, after the radioactive spider bites the Miles Morales version of spiderman, his cells actually begin to undergo radioactive decay or cellular decay. This situation is very similar to the radioactive atom in Schrödinger’s cat. The average 70 kg human has around 7 × 1027 atoms in his/her body, which undergo radioactive decay at the rate of 5000 times per second. All these atomic nuclei are constantly in superposition of decayed and not decayed, so when they do decay, it means those nuclei get entangled with the environment, and the wave-function branches out, creating more and more copies of you at a tremendous rate. If this applies to an average human being, it can definitely apply to Miles Morales, whose decay rate is probably accelerated thanks to the radioactive spider.
- Just like how the two copies of seeing the cat dead and seeing the cat alive could exist in their own individual realities, that can never interact, the many copies of Miles Morales cannot interact. But my main point here was, even though there are so many versions of Spider Man from different dimensions/realities (Gwen Stacy, Peter Parker, etc.) it is actually impossible to for any of them to experience anything in another reality as each reality is unaffected by the other. But when a particle accelerator comes into play, and then different Spider-Men meet through it, this kind of stuff could be possible. Particle accelerators are extremely huge machines, which use electromagnetic fields to propel charged particles at very high speeds, and it is mainly used for research in particle physics. The very famous Large Hadron Collider at CERN was conducting research by thinking of creating tiny black holes. It hasn’t been done yet due to safety risks and other reasons. But speculations have come to show that if there were tiny black holes being created, it could be a gateway to different dimensions and parallel realities. I am not an expert on the subject, so I wont get into the details of it. This is all under speculation, and since it borders on philosophy as well, we cannot be sure. But if it is true, then who knows, maybe the events in Spider-Verse could be, maybe, possible with a particle. There probably other things that don’t make sense, but these were the only ones I could think of under my circumstances. Although I am quite sure that key themes in the movie did revolve around a Multiverse, as the name of the movie hints: Spider-verse.
Of course, Many-World Interpretation is still a huge debate in the science community and it hasn’t been proven yet. Some physicists think it’s too complicated, while others are infatuated by the idea of it. This does mean that the whole idea of ‘The Multiverse’ is not proved to exist, but it could be possible. Even if it is a low probability world, there could be a copy of you being president, or winning the Wimbledon, all in different realities. Even if it is a topic of uncertainty, it is perhaps fun to ponder over how our universe may work if there was a multiverse.
Featured Image Courtesy – Pinterest