Peter Parker’s Uncle Ben told him that “with great power, comes great responsibility”, but Adam Weiner, physics teacher and author of the book Don’t Try This at Home! The Physics of Hollywood Movies, says that having superpowers could come with some great drawbacks, too.

Faster Than a Speeding Bullet

According to Weiner, having Superman save you could actually end up killing you. “The story goes that Superman is able to fly faster than a speeding bullet. The issue is that speed doesn’t kill – acceleration does,” says Weiner. “Travelling at a constant speed is indistinguishable from not being in motion – that’s Newton’s First Law. That’s why if you’re on an aeroplane at cruising speed and the ride is smooth, everything behaves pretty much as if you were sitting in your lounge,” says Weiner. “What can be dangerous is when your speed changes – that is called acceleration. Accelerations require a force. The bigger the acceleration, the bigger the force required and that is what you feel the effects of. So it’s not moving fast that is the issue – it’s how long it takes to get up to that speed”.

Once acceleration rates get up to 8 or 10 g’s you might start to get in trouble, according to Weiner. “Say Superman flies across the country at a speed faster than a bullet – say 3000km/h. If he takes 15 minutes to get up to speed, that will give him an acceleration rate of only one tenth of a g – no problem. However, if he gets up to speed in one second, then the acceleration rate is about 90 g’s, which would kill a normal human being. So if Superman just rescued you and is carrying you home, you’d better be sure he is cognisant of his acceleration speed, or he might have saved you for nothing!”

Stark Reality

Who wouldn’t want to be Iron Man? Tony Stark is super-rich, funny and gets to snog Gwyneth Paltrow and Scarlett Johannson. Oh, and also flies around and save the world in an almost-indestructible suit. But how would the suit fare in the real world? “If you look at the Iron Man suit as a jet pack, the problem is fuel,” says Weiner. “A normal jet pack has only a few seconds worth of thrust, because it requires a huge quantity of energy and therefore a huge amount of fuel”.

Jet packs work according to Newton’s Third Law, the law of action and reaction. The downward push on the fuel out the jet pack results in a reaction force back on the jet pack, which is what thrusts you off of the ground. “However, apparently Iron Man’s energy source is not typical chemical energy such as used in rocket fuel. His ‘Arc’ power source appears to be a sort of sort of nuclear reactor that allows him to get a lot more energy out of his fuel supply. However, in order to generate the same kind of thrust, you would still need to apply the ‘action-reaction’ principle. It would require expelling the product of those nuclear reactions out of the suit at very high velocities. He’d better have some pretty good shielding on that nuclear reactor!”

Because his suit acts a lot like a fighter jet, Iron Man will experience forces similar to that of a pilot. But, according to Weiner, because Tony Stark is not strapped into a seat in an immobile position, his suit must be completely rigid when he applies thrust. “If not, if he is shooting fuel out of ‘jets’ on his hands, for example, the torques on his wrists at those accelerations would be enough to break them,” says Weiner. “However, if these issues are accounted for and his suit inhibits flexibility while thrusting, maybe he’ll be okay”.

Magnetic Personality

X-Men’s Magneto is a terrifying villain, using the ability to control magnetic fields to wreak havoc. “Before we talk about how the magnetic fields he produces would affect his surroundings, it’s interesting to discuss how he produces magnetic fields in the first place,” says Weiner. “Magnetic fields are caused by moving electric charges, i.e. electric currents. In order for Magneto to create the magnetism that we see in the movies and comic books, he would have to have electric currents of thousands of Amperes flowing through him. It takes only a few thousandths of an Amp to disrupt electrical signals to the heart, so Magneto must have a uniquely mutated heart, capable of withstanding enormous currents. Also, the amount of heat these currents would generate in a human body would be a big problem too”.

In terms of how the magnetic field he produces would affect other humans, consider that oscillating magnetic fields like microwaves and x-rays can have a damaging effect on the human body. “If the field Magneto generated were static, instead, it would have to be incredibly large to be dangerous. We do know that static magnetic fields exert forces on moving electric charges so it is certainly possible that a large enough static field might affect electrical signals in the body, like the heart.

Magneto is able to generate static fields large enough to lift submarines, so it could well be that any humans in the vicinity may suffer heart failure,” says Weiner. If that doesn’t kill you, the effects of the field on magnetic objects might. “Magneto also seems to be able to target and direct the fields he creates to specific regions, so anyone outside the field region shouldn’t be affected,” says Weiner. “However, within the field regions, which are strong enough to lift cars and submarines into the air, loose ferromagnetic material would be flying around like shrapnel – which would actually make a pretty cool effect in a movie!”

Star Power

He’s funny and he has great taste in music, but Guardians of the Galaxy’s ‘Star-Lord’ is one of the most offbeat superheroes in the Marvel Universe. He has a cybernetic implant in his eye that allows him to see all energy spectrums and a memory chip in his brain that give him 100% recall – and Weiner reckons it wouldn’t be a giant leap to see that kind of technology in the real world.

“Currently, brain implants are being used in people with spinal cord injuries which allow then to move robotic limbs. So there exists the ability to connect brain activity to electrical signals remotely via implants,” he says. “Whether or not there might be some way to store actual memories on a chip I have no idea, but it seems plausible”.

The eye implant too, may be plausible. Human retinas are able to detect light within a certain range of the electromagnetic spectrum – known as the ‘visible light spectrum’. “Some animals have eyes that can perceive light outside of our visible spectrum. The cells in their retinas are stimulated by regions of the electromagnetic radiation that do not affect ours. However, even now, scientists are working on eye implants for blind people which are triggered by infrared radiation – light from outside the visible spectrum,” says Weiner. “The implants then stimulate the retina and therefore produce images that are perceived by the brain. So it doesn’t seem too far of a stretch to create an implant that will stimulate the retina at a variety of non-visible light frequencies”. Superpowers in our lifetime!

Superpower Snacks

One of the major stumbling blocks to making superpowers a reality, is the amount of energy required to power them, according to Weiner. “The question is ‘where do superheroes get it’? Because they need a superhuman amount,” says Weiner. All living animals that exist in the real world get energy by metabolising food – but this just wouldn’t do the job for a superhero. “Let’s take the X-Men for example – the mutant Storm. She has the ability to create weather and specifically, she can generate lightning bolts. The amount of energy in a single lightning bolt would be equivalent to the amount of energy released in metabolizing 60 times the recommended daily amount of calories for an adult female. And of course all this energy would have to be converted into the energy of the lightning bolt,” he says. “People say that Storm isn’t actually creating the lightning bolt but ‘simply’ changing the weather. It doesn’t matter – the energy that would have to be transmitted from her to do this would be way more than just the energy in a single lightning bolt discharge”.

This problem permeates the super hero world to various degrees. “Realistically, in order to produce the vast amounts of energy some of these guys emit on a regular basis would require that they eat non-stop, 24 hours a day, and even then it probably wouldn’t be enough,” says Weiner. “The only way out of the problem is they get their energy in another way. For example if their stomachs have mutated into some type of biological nuclear fusion reactor, then the food mass would provide more than enough energy to do the job!”

*A version of this story appeared in khuluma in June 2018