The Science and Law of Physics Behind Tenet is Explained

Christopher Nolan’s projects are known for their metaphysical and epistemological themes exploring the construction of time, human morality, and the malleable nature of personality identity and memory.

The science fiction movies like Interstellar and Inception offer a unique approach to the time travel genre. However, the question arises about how accurate the scientific facts are used in the movies? The Oscar winner hired a theoretical physicist Kip Throne, who helped the filmmaker with the scientific theories, and the law of physics and time. While Nolan also takes artistic liberties with the laws.

Nolan’s recent movie Tenet is one of such sci-fi films based on the time inversion. Throne was also consulted for the film’s scientific aspects. Nolan conceived Tenet’s idea around twenty years ago and started to work on the screenplay in 2014. It stars John David Washington as the protagonist alongside Robert Pattinson, Dimple Kapadia, Kenneth Branagh, Elizabeth Debicki, and Michael Caine.

The movie’s plot follows the CIA agent, the ‘Protagonist’ who works as an undercover operation at the opera house for the organization named, Tenet. The agent manipulates the linear flow of time to avoid World War III. He learns that the war is being triggered by the future, where people use some kind of technology to invert the people or objects by reversing the “entropy.” The change in the “entropy” helps the agent to move backward in time instead of forward.

The organization Tenet also existed in the future to stop the antagonist from setting the doomsday weapon that will wipe out the present and the past. During an interview with Screen Rant, the theoretical physicist at the University of Oxford, Dr. Lucian Harland-Lang, shared some of his knowledge regarding physics laws and physics concepts, which will help the moviegoers understand the movie better. The physicist worked in the field of theoretical physics and collected the real data at the Large Hadron Collider (LHC). LHC is the highest energy particle collider built by the European Organization for Nuclear Research (aka CERN). The huge device helped the researchers to discover the Higgs boson (mainstream media called it the “God particle”) and some new particles.

However, Nolan’s movie does not seem like a particle physics film; but particles are the center of mechanics and time travel.

Entropy And How It Associates With Tenet

In scientific terms, “entropy” is a physical property that signifies disorder or randomness. Hence the more disorders particles have, the more entropy it possesses. With that concept, gases’ entropy is the highest, while solids have the lowest entropy. The entropy concept is used in classical thermodynamics, principles of information theory, and microscopic description of nature in statistical physics. Entropy predicts whether a particular process is reversible or irreversible. The constant expansion of the universe shows that it is becoming more chaotic over time.

Physicist Arthur Eddington, who first speculated the conversion of hydrogen into helium is by the source of fusion, explained the entropy as an “arrow of time.” James R. Newman, the great mathematician, co-wrote the book Mathematics and the Imagination, defining it as “the general trend of the universe toward death and disorder.” In comparison, many say that entropy is a closed system that can only increase.

If you burn a paper, the paper can turn into ashes (becoming more random or disorder) as time is moving forward. The ashes will never be turned into the paper (less disorder form). The flow of entropy is the only thing preventing the ashes from converting into paper again, as all other physics laws allow the reversible process.

In this contradiction between different laws of physics, Harland-Lang describes entropy as a “probability argument.” He said that physically speaking, the reversible process of ashes reforming into a paper is possible by other laws.

The particle theorist explained that the probability of reversing entropy is “tending towards zero,” but that is not “zero.” Hence it creates a paradox that if you are not used to seeing ashes turning into paper, it does not mean they would not.

Director Nolan said that if one could invert an object’s entropy, you can also reverse the time flow. However, he does not say that the film’s science is 100% accurate, but he claims that it is based on credible physics.

Theoretical Physics Used In Tenet

The film’s central plot is the objects, and people are going through a time inversion based on a theory by physicists Richard Feynman and John Wheeler.

Physicists believe in the theory that every particle that we know has an opposite sister, known as “anti-particle.” This particle has the same mass as the particle but opposite physical charges (i.e., electric charges). For example, an antiparticle electron is anti-electron (or positron). Similarly, we have antiprotons, antineutrons, and collectively they are known as “antimatter.”

The positron has a charge of +1 e, a half spin, and has the same mass as an electron. These antiparticles are produced naturally after the natural decaying of radioactive β+. Another kind of antiparticle, antineutrinos produced by the natural decaying of radioactive β−. In many experiments, the researchers have found evidence of positrons in the primary cosmic rays, amounting to less than 1% of particles. A particle accelerator device can also create positrons like LHC.

However, the Feynman-Wheeler theory states that if we can flow time backward, then electrons’ reverse flow could look like a positron. Hence moving backward in time can result in the positron co-existing with its former self or even colliding with each other.

Christopher Nolan did not explain the whole theory behind it; instead, he referred to the idea to reverse the direction of time-based on the Feynman-Wheeler theory. In one of the sequences, the protagonist, Washington, is fighting with an inverted man, who is later revealed as himself. It depicts that two men are fighting in different states of being. According to Feynman-Wheeler’s theory, a particle and antiparticle could be the same particle moving in the opposite flow of time.

Harland-Lang cautions that it is just a theoretical concept, and it does not mean whenever an antiparticle forms, we undergo a time inversion. Tenet used the theory and replaced the particle with inverted people.

Is Tenet Scientifically Accurate?

With the movie, there are big questions that arise, is reversing the flow of entropy can cause the backward movement of person and object? Harland-Lang said, no, he does not think so. He added, Nolan has created a world imagining if that could possible, and Tenet has raised some curious questions about time.

It is difficult to separate our experience of time, as we have the signposts of time, paper burning, people aging, mountains eroding, etc. Hence it seems the same thing to us. Still, if you are lost in time and have no idea which way the time is flowing, observe a closed room’s entropy. The direction of the time can be considered by noticing the direction of increasing the system’s entropy.

Source: The Science and Law of Physics Behind Tenet is Explained