Have you ever thought if the superpowers you’ve seen in action films actually make sense in real life?
Before the Marvel Cinematic Universe became the juggernaut that it is today in box office, the most famous superhero was probably Superman. Most of us grew up idolizing Superman and playing with his action figures. Super strength is pretty amazing and who doesn’t want to have it, right?
Superpowers in Real Life #1: Super Strength
However, comic book and movie writers often do not care if the superpowers that they show in comics or on screen are realistic. What’s important to them is to create spectacular images and scenes to help improve the comic-book reading or movie-going experience.
Superheroes are works of fiction and of course, you would not expect them to be 100% realistic. The problem is, even if the physics behind these superpowers in the stories is wrong, it still gives a long-lasting false understanding of the physics concepts at play.
The Definition of Super Strength in Real Life
The concept of super strength is fairly straightforward. The person having it, like Superman, simply has a body that is strong enough to exert a very large amount of force. We can also assume that he has a body that is durable enough to sustain the stress and damage that this may cause. For example, Superman will never experience pulling a muscle or hurting his back while lifting something very heavy, right?
With these definitions out of the way, we can now start seeing and understanding the superpowers shown in comics and on screen are denying real-life physics.
Problem #1: The Concept of Pressure
Superman may have the strength to stop a moving a train or the ability to carry large vehicles. In the recent movie Justice League, w can see Superman carrying a whole building! From our definition, a person having super strength like Superman, may be able to exert a force so large that it can counteract a whole building’s weight. But, in carrying objects in real life (and applying forces in general), the amount of force is not the only important factor at play.
Another significant factor is the amount of pressure exerted. Pressure is defined as force divided by the area in which the force is applied. There are two ways to increase the pressure: increase the force or decrease the area.
No matter how strong a punch might be, it would never cause that part of your skin to bleed. But prick it with a needle and it will certainly bleed. What’s the difference? The needle can exert much larger pressure because it applies force on a very, very small amount of area.
Let’s go back to our example of Superman carrying a whole building. Don’t worry if you hate math, we will try to analyze this by only using the concepts and without numbers.
This is a very simple force diagram about that event. The whole building has a certain weight. To carry it, Superman must exert a force upward that is equal to that weight. Since Superman has super strength, he can certainly exert a force that is that large. Therefore, he can carry the building. There is nothing wrong with this, except that the concept of pressure is not taken into account at all.
As we can see, Superman is supporting the entire building with his two bare hands. Therefore, he must exert a very large amount of force (equal to the total weight of the building) on an area that is just as big as his two hands. The pressure exerted by Superman would be very, very large.
So what is the problem? The problem lies in the fact that the concrete with which the building is made would not be able to withstand this large amount of pressure exerted by Superman. This will cause it to break at the point of contact in the same way that your skin breaks upon contact with a needle.
Let’s see a different example to understand this concept. When we are grocery shopping, why don’t the brown paper bags that we use to carry our grocery have handles like the ones that are used when we are buying clothes?
You know the answer. The paper bag would break if you carry something heavy inside it using a handle. When a paper bag is heavy, we know that the proper way to carry it is by supporting it in the way that is shown in the picture below.
Superman carrying a whole building using just his bare hands is the equivalent to carrying a large brown paper bag full of groceries with a handle. Yes, you certainly have the strength to carry everything that is in it, but the paper bag itself will break if you apply that force on an area as small as that of which the handle is in contact with the bag.
This concept does not only apply to this particular scene, but also every time someone with super strength carries something that is really heavy.
Problem #2: Superheroes Lifting Heavy Objects that are in an Isolated System
An isolated system is defined as a collection of two or more objects that are “isolated” from all other objects so that they cannot physically interact with them. To understand this further, we will look at this scene from Batman V Superman: Dawn of Justice where Superman is pulling a giant ship through ice.
We already know how the concept of pressure can cause problems in the realism of this scene. For now, let us assume that the anchor chain’s attachment point on the boat is so strong that it can withstand the intense pressure that would have been applied to it.
The ship has a very large amount of mass, which means that a very large amount of force would also be required to pull it. But again, Superman has super strength so he can certainly still pull it. If we consider that Superman and the ship is in an isolated system, which simply means that we ignore every other object apart from them, we would have no problem. The problem has to do with their surroundings, particularly, the ice that Superman is walking on.
To be able to walk while dragging the ship behind him, Superman’s feet should be able to exert a very large amount of force on the ice. With his super strength, he can easily do that. But would the ice under his feet be able to sustain this force? No. This would be exactly the same if he was instead carrying the ship instead of dragging it while walking on the ice. The ice would not be able to support their weight.
Again, this does not only apply to this particular scene. For example, there is a very popular image from a Superman comic that has been used for fun as a meme. We know that Superman has the strength to exert a force strong enough to stop the moving train. But to do that (we will assume that he is not flying), he must exert that same amount of force on the ground with his feet. The ground would obviously never be able to support that amount of force and thus, he would not be able to save the little boy.
Problem #3: Catching a Falling Damsel in Distress Never Works in Real Life
This is already explained in this video, but we will still explain it from a different angle. The video has also touched on the concept of pressure on this video. However, why wouldn’t this superpower work in real life? Because catching a falling person never works due to impulse.
Impulse, in physics, is what is needed to change in momentum. It is the product of the force and the time in which that force is applied. This means that force and time are inversely proportional. If you change an object’s momentum in a short amount of time, you must apply a large amount of force. If you want to change its momentum for a longer amount of time, you can just apply a small amount of force.
A woman falling from a tall building would have momentum associated with her downwards movement. This means that you have to apply an impulse to stop her fall or decrease her momentum to zero. Catching her would in your arms not be different from her falling on the concrete because of her sudden stop. A sudden stop means a small amount of time, and therefore, a large amount of force.
Fire-fighters usually catch suicidal people that try to jump off a building using a net. This way, the person won’t experience the sudden stop. This lengthens the time it takes for her to stop and therefore, lessens the force required. This is also the reason why in parkour, when they jump from a high place, they usually roll when hitting the ground. This also lengthens the amount of time for them to stop.
This article is not meant to criticize these movies, comic books and characters, but to help people further understand the physics behind these superpowers and get to know what it would be like to have them in real life.