But one thing doesn’t cancel out the other. Some movies, even if they are over-the-top (and let’s face it, who doesn’t love that?) and purely fictional, stick to scientific principles. What they say makes sense, basically. Others, however, don’t come close to accurately representing what they’re trying to depict, leaving the scientists and experts in the audience shaking their heads. That’s why we’re going to talk about three movies that sparked a lot of discussion in the world of science. How much truth do they really hold?

Warning: This article contains some major spoilers. If you haven’t seen these movies and don’t want to know what happens, go watch them and come back afterward. We’re sure you’ll love them!

The Martian (2015)

Dir. Ridley Scott

Ridley Scott loves a good sci-fi movie. And that’s exactly what he delivered in 2015 with The Martian, a great science fiction film. It tells the story of a NASA astronaut named Mark Watney (Matt Damon) who travels to Mars with his crew for an exploration mission. He’s presumed dead after a sandstorm forces the crew to abort the mission and leave without him. As a result, Mark finds himself stranded on the planet with supplies for 300 sols (1 sol is a Martian day, roughly equivalent to 24 hours and 40 minutes, or about 309 Earth days), completely alone.

Luckily, Mark isn’t just an average person who’d succumb to an existential crisis within three days. He’s a trained astronaut, engineer, and botanist who manages to survive (with some serious setbacks) long enough to reach the Schiaparelli crater, where the arrival of the Ares IV mission will save his life. But here’s the million-dollar question: how does he survive in such conditions? Could this actually happen in real life, or is it completely far-fetched?

The movie’s story is based on a book of the same name by Andy Weir, a science fiction writer and software engineer who described himself to Forbes as a “space nerd.” With that in mind, it’s fair to say his fascination with space drove him to write a scientifically grounded, informed, and logical book; with a few liberties, of course. Ridley Scott’s big-screen adaptation does it justice, and here’s why.

Let’s start with how Watney gets food: yes, the famous potatoes sent to Mars for the crew’s Thanksgiving dinner. Good thing he’s a botanist! Using the preserved feces of the crew, he creates fertilizer to grow those 12 potatoes and produce more. This process seems plausible at first glance. NASA has even conducted simulations of growing food on Mars, with great success. Maybe they’re hinting at something?

After all this, our favorite botanist realizes that even with plenty of potatoes, he’ll need water to grow them. Smart thinking. Watney knows the recipe, too. Specifically, he mentions that each cubic meter of soil needs 40 liters of water, so he gets to work. First, he takes the hydrazine (rocket fuel) left over from the ship and passes it through an iridium catalyst (handy things astronauts have!) to separate it into nitrogen and hydrogen. Then, he isolates the hydrogen, releases it in a small, sealed area, combines it with oxygen, and burns it to produce water. The experiment backfires (literally) and he gets smacked around pretty hard. But what matters is that this method is scientifically sound. Extracting water this way is indeed possible, albeit extremely risky. Watney even jokes in the movie: “NASA doesn’t like fire because fire makes everyone die in space.” Wise words! However, let’s not kid ourselves… getting hydrazine wouldn’t be that easy for the average person.

But not everything is accurate in this movie… Remember the storm that left Watney stranded? In both the book and the movie, it’s depicted as a raging, violent storm, but such a scenario is unlikely on Mars. Dust storms are indeed common on the red planet (sometimes they’re so massive they can be seen from Earth with a telescope!), but NASA points out that the depiction of the wind isn’t entirely accurate. Due to Mars’ thin atmosphere, much stronger winds would be required to knock over an entire crew and their equipment. Andy Weir knew this, but he decided to leave it as-is in his story. Fair enough, Andy, we love this kind of drama!

Tenet (2020)

Dir. Christopher Nolan

If you walked out of Tenet (2020) feeling like you understood every detail, congratulations, you probably have an IQ well above average. Christopher Nolan’s two-and-a-half-hour science rollercoaster certainly leaves no one indifferent. This intense film follows “The Protagonist” (John David Washington), who finds himself caught in a web of international espionage involving futuristic technology designed to prevent the outbreak of World War III. Along the way, he encounters Neil (Robert Pattinson), who seems to know more about what’s happening than The Protagonist himself. Intrigued? Let’s dive in.

The film delves into several scientific conundrums, but the most intriguing is its focus on entropy, which ties into the second law of thermodynamics. There are four laws of thermodynamics (originally three—1, 2, and 3—but later a “zeroth” law was added as a foundational principle), and they’re all crucial for understanding how energy behaves, flows, and transforms. Understanding energy behavior also helps us grasp the workings of the universe—a mystery humanity continues to unravel.

The second law, entropy, is our star here. In essence, every system tends toward disorder or chaos over time. What does that mean? It means that energy naturally disperses, increasing entropy as it spreads. National Geographic (2024) illustrates this with a relatable example: “Imagine a cup of hot coffee placed in a room with a cooler temperature. Initially, the heat is concentrated in the cup, but over time, it disperses into the room. This is an example of increasing entropy caused by the chaotic distribution of thermal energy.”

This phenomenon is closely tied to the irreversibility of systems, which asserts that you can’t perfectly reverse a process without altering its outcome. For instance, you can’t un-break your family’s favorite vase as if pressing “Ctrl + Z.” Unfortunately, no system in real life is perfectly reversible.

But, what if entropy could be reversed? That is precisely what Christopher Nolan tries to convey in Tenet, in a completely and utterly fictional way, it should be noted.

In one of the scenes early on in the movie, we see a series of events leading the protagonist to an organization called Tenet, where he meets Laura (Clémence Poésy), a scientist who works with technology from the future. It’s her job to explain to the protagonist how all this technology works, and that’s when we see the first fantastic artifact of the entire film: a wall full of bullet holes. You read that right, just a simple wall with bullet holes. Laura gives the protagonist a gun and tells him to shoot it at the wall. The protagonist, however, is confused, as he sees that the gun is not loaded. Nevertheless, he points it at the wall and fires. Everyone knows what would happen if Tenet were just any other movie: the gun, being unloaded, would do absolutely nothing. In this scene, however, when he fires, the protagonist is confused; he finds that the gun has done something strange. There’s one less hole in the wall, and the gun’s magazine now contains a bullet, even though it was empty before the shot.

That’s when Laura explains to the protagonist (and the audience) that this technology is based on entropy and that, in the future, someone has managed to reverse it. She shows him two bullets: one is the bullet he just fired, and the other is a completely normal bullet. She explains that one of them is like the two of them, it travels forward in time. The other, however, has reversed entropy, meaning that, to our eyes, its motion is reversed. If we go back to the earlier example, it would be like returning your family’s vase to its original state by reversing its entropy, but in a much more violent context.

To better understand this, imagine a box filled with particles. If those particles are stationary and contained within the box, the entropy is equal to 0. However, if the box were to break, all the particles would scatter, dispersing their energy and making the entropy greater than 0, positive, in other words. Entropy is greater than zero in everything we know in real life; it always tends to increase, and that’s why space is constantly expanding. Fiction, however, takes us down a different path. If entropy were negative (less than zero, as it is in Tenet) that box that had already been destroyed would go back in time, and the particles would return to being inside it.

And in this incredibly complex way, Tenet (the movie, not the organization) manages to explain the second law of thermodynamics in a very entertaining way. After the gun scene, many more follow, featuring stunning visuals and mind-blowing technology that are worth seeing. But for that, you’ll need to stop reading and hit play.

Ant-Man and The Wasp 3: Quantumania (2023)

Dir. Peyton reed

Oh, what has our favorite superhero gotten himself into this time? Since this is the third film in the Ant-Man trilogy (so far), let’s recap from the beginning to set the stage for this movie. In the first film, Scott Lang (Paul Rudd) is blown away when Dr. Pym (Michael Douglas) gives him a suit that makes him ultra-small, allowing him to visit the quantum realm for the first time, accidentally, of course. This one’s a must-watch. The second film, however, is a bit trickier, as this time, they enter the quantum realm on purpose to rescue Janet, Dr. Pym’s wife (Michelle Pfeiffer) and Hope Van Dyne’s (Evangeline Lily) mother, who got stuck there permanently after becoming subatomic. Don’t worry; they manage to rescue her. But then comes the big thing everyone knows about: Thanos and that snap. And what does that have to do with our dear Ant-Man? Well, while conducting experiments, Scott had entered the quantum realm, and the snap happened right while he was inside. He wasn’t affected, but unfortunately, the three people who could pull him out of the nano-world were part of the 50% of the universe’s population that vanished. Total bummer.

Which brings us to the third film, set after Avengers: Endgame, where Scott Lang has returned from the subatomic world with a lot to share with his family and scientific team. This time, Janet is back with her family, and Scott’s daughter, Cassie (Kathryn Newton), has developed an obsession with the quantum realm. She builds a gadget to observe the quantum realm without actually entering it, but things don’t go as planned. The device ends up trapping the whole family inside the tiny world.

Even though the movie is literally titled Quantumania, the truth is, quantum physics doesn’t exactly shine in it. Still, there are two key points worth focusing on to compare the movie to real-world science. The first is the quantum realm itself. Big words. It’s where the entire movie takes place, with Kang the Conqueror (Jonathan Majors), the villain of this story, ruling over an entire world of microscopic beings at his mercy. Yep, you read that right: it’s a subatomic world inhabited by subatomic creatures, living in an intelligent civilization with surreal landscapes. It’s led by a villain exiled there because of his misdeeds against humanity and its universes. But let’s get to the point. Dr. Michael Kolodrubetz from the University of Texas makes it clear: “The quantum realm isn’t real.” As he explains, quantum physics focuses on subatomic particles. Since the building blocks of any matter on Earth are these same particles, we’re already living in a quantum world. However, because of its size, humans are far too large to follow the rules of quantum physics and instead abide by the laws of classical physics.

Moreover, if such a “realm” existed, we’d never be able to enter it. As Medium points out, we’d need to shrink to a size smaller than a subatomic particle, such as a proton, which has a diameter of approximately 1,7/10¹5 meters, about 10 million times smaller than the smallest virus we know. So, unless someone can create real-life Pym Particles, this part of the movie lands squarely in the category of pure fiction.

The second point worth mentioning is the scene where Scott enters a “probability storm” to retrieve an item that Kang needs to escape the quantum realm and release Cassie, who he’s holding hostage. Inside the storm, Scott starts multiplying, creating a place filled with billions of versions of himself. Understandably, the protagonist is completely overwhelmed. The dialogue in this scene unfolds as follows (there’s a lot of back-and-forth between the different Scotts, so we’ve trimmed it to focus on the explanation):

SCOTT LANG

Why am I seeing another me?

M.O.D.O.K.

You’re seeing the possibility of another you. You’re in a probability storm.

SCOTT LANG

What does that mean?

M.O.D.O.K.

All the decisions you could make exist at once. You’re inside Schrödinger’s box, and you’re the cat.

This scene represents quantum superposition, where in quantum mechanics, particles can exist in multiple states simultaneously until observed, at which point they collapse into a single state. In the case of Schrödinger’s cat, the cat inside the box is both alive and dead until it’s observed. It can exist in both states because we lack the capacity to see inside the box without opening it. But once the box is opened, and the cat is observed, it collapses into one deterministic state: either alive or dead. The movie provides a visual metaphor for this phenomenon, showing the protagonist and all his chaotic variations aligning under a single objective to work together and “collapse” into a single state, Scott as the one and only Scott in the situation. It’s a bit convoluted, but the visual metaphor is stunning to watch.

Let’s hope Scott Lang stops getting himself into so much trouble. Even a superhero of his caliber probably appreciates a little peace and quiet.