We all know that superheroes like Superman or Thor are completely impossible. But just for the sake of argument, are there any superpowers that could actually exist in the real world? We assembled a panel of experts to find out.
We asked experts in the field of superhero physics, all of whom have written books explaining the science (or lack thereof) behind the most iconic superheroes. I offered up some famous, seemingly impossible superpowers - flight, super speed, invisibility, telepathy, teleportation, and energy manipulation - and then asked them for their choice of the most plausible superpower. Our first expert provided a breakdown of the six superpowers I named, while the others suggested some other potentially possible superpowers.
Based on their answers, I think I can say this much: if superheroes ever do walk the Earth, we'll never see them coming. You'll see why in their answers...
Sidney Perkowitz, author of Hollywood Science and Candler Professor of Physics at Emory University:
Potentially possible: Invisibility.
There has been enough progress in invisibility cloaks, since the first one was made five years ago, that these could actually exist down the road. Right now, we have cloaks that can hide objects a few inches high under visible light and there are schemes to make a real Harry Potter-like wrap-around cloak. Readers who want to know more about real-life invisibility can read my new book Slow Light: Invisibility, Teleportation, and Other Mysteries of Light.
Possible but impractical: flight/super speed.
I think the military has tested jet packs for individual soldiers, but only for limited jumps. The problem is, how to carry enough fuel and maintain control for true, high-speed long-distance flight such as is seen in the Iron Man films?
Impossible or unproven: teleportation, telepathy, and energy manipulation.
It is true that scientists can teleport photons and clusters of atoms and this is already used for quantum cryptography; but the Uncertaintly Principle in quantum physics says something the size of a person can never be teleported. So atom size teleportation is possible; human-size teleportation is not. Some people claim anecdotal evidence of mind-to-mind communication, but I have never seen convincing scientific evidence, or a theory that provides a believable physical mechanism for this. Along similar lines, there isn't any scientific theory I know of that would explain how a superhero could control various forms of energy by mind alone.
As far as superheroes that are the most realistic from a physics point of view - I would have to say Batman, with one exception. Given the number of times that the Caped Crusader has been knocked unconscious over his > 60 years of crime fighting, the fact that he has avoided permanent brain damage suggests some sort of Homer Simpson-like skull padding. A hidden superpower?
Iron Man is also pretty realistic, once you accept an arc reactor power supply the size of a hockey puck capable of generating the power of three nuclear power plants. Once you have a near unlimited source of energy, jet boots (feet based jet packs), exo-skeletons, palm mounted thrusters (repulser rays), are all within the realm of current technology.
Granting characters a one-time exception from the laws of nature, then one of the more realistic super powers is telepathy. After all, when you think, ionic current along and between neurons generate very weak electromagnetic fields. These electromagnetic waves emanating from your head in deep thought are a billion times weaker than the radio waves that surround you right now. (We never think about the fact that we live in a sea of radio waves, except when we can't get a cell phone signal).
Prof. X has the mutant ability to amplify these weak EM waves generated by your brain, and decode them to discern the thoughts that generated them - not unlike the reverse television hacking of van Eck phreaking. Similarly, he can broadcast waves of sufficient intensity to stimulate neuronal activity that would force certain motor activity.
Not as far fetched as you may think. Professor Bin He in the Dept of Biomedical Engineering at the University of Minnesota is working of translating the signals generated when a person is watching a computer screen, and translating the information into voltages that are sent to the computer. The upshot is that a suitably trained volunteer can move a mouse along a computer screen by only thinking of where they want the cursor to move.
It doesn't take a superpower to know that right now you're thinking that it might be a good time to invest in a tinfoil helmet!
Adam Weiner, physics teacher and author of Don't Try This at Home! The Physics of Hollywood Movies:
My vote would be for invisibility. Current research into substances called "metamaterials" lend themselves to the possibility. Basically metamaterials have negative indices of refraction which means that light originating from behind an object made of a metamaterial could be bent around it such that an observer would see whatever is behind the object but not the object itself. (There is a pretty good explanation of metamaterials on Wikipedia.)
As of now these negative indices of refraction only apply to a narrow range of frequencies but theoretically it might be possible to expand this to cover the visible spectrum. Now it might be cheating to call this a superpower since it's really a technology, however maybe given how most superheroes are created maybe with the right exposure to high energy radiation a fledgling superhero's superficial layers might be altered appropriately! Anyway it's a lot more plausible than shooting flaming fire bolts out of your eyes, or flying, or changing the weather or...
E. Paul Zehr, author of Becoming Batman and Inventing Iron Man and Professor & Director of the Centre for Biomedical Research at the University of Victoria:
My own penchant is for the human basis for superpowers — hence Becoming Batman and Inventing Iron Man. If we consider Iron Man, we are getting close to being able to "fly" without being "inside" an aircraft, as in Yves Rossy. With some major advances in power source, that kind of technologically enhanced powered flight is close. Maybe also a bit like Angel in the X-Men?
What I can also see is a kind of technological telekinesis. That is, manipulating objects at a distance. Or, rather, manipulating humans (and other mammals) from a distance by controlling their nervous systems. I can see the outcomes of advances in brain machine interface (and which is central to my Iron Man book) as a way to lead to increased knowledge of how to "hack" the human nervous system.
What I am thinking of is some kind of projectile neural interface that would connect to the head of someone (let's say a bad guy) when shot out from someone (let's say the good guy). Now the interface activates and controls the body of the "hacked" bad guy. He becomes compliant and is basically "remote controlled" by the hero.
This is essentially the reverse of brain machine interface where the brain of the user is supposed to control the machine (like the Iron Man suit). Now, that interface is used in reverse-to control the user from an external person. Please note that this isn't the same idea as a large voltage pulse as in a Taser which disrupts all neural activity and incapacitates. Instead this could be used for very fine and "normal looking" motor control. Except it would be control imposed by an external user.