Could Superman's X-Ray Vision Really Exist?

So how does Superman do it! He can see through buildings and clothing (he checks out Lois Lane's underwear in Superman 1 - more on this later). Many have attempted to answer this question of the ages yet few have explored this in as much depth as J.B. Pittenger who published a study in the journal Perception back in the stone ages (1983) entitled "On the plausibility of superman's x-ray vision"

But first, before we get into the meat of the paper, lets see what others around the InterWebs have said about Superman's amazing seeing through underwear powers.

In Correcting Misconceptions about Superman Lorenzo Vincent Aurelius says:

What of the other powers? Superman's X-ray vision is not truly x-ray vision. What do you think -- Superman's eyes emit x-rays, which he uses to see with? That's not how x-rays work. They require a source that aims the x-rays toward the receiving end, whether it be eyes or photographic film. No, Superman's vision involves sensing energy fields that have hitherto been unidentified by human science. These energy fields surround and pervade all forms of matter, varying by density and vibratory rate, according to the density and composition of the object. In other words, Superman is seeing the subtle energy fields involved in the inter-transformation of energy into matter. His ability to distinguish those fields depends upon the "signal-to-noise ratio" between any object he is sensing and any intervening objects. Lead, being dense, has a field so dense that less-dense fields behind it are hard to distinguish. Gold has the same effect. But since people do not commonly use gold as shielding, it has not been written about. So people think, "Lead blocks x-rays; lead blocks Superman's x-ray vision."

Ok so we need energy fields unidentified by human science. I'll go out on a limb and guess that the scientists of Superman's home planet have discovered this energy field but didn't include it in that weird crystal house/computer/whatever thing. has a number of great speculations as well:

Just like rods and cones in the human eye, Superman possibly has x-ray detecting crystals like Silicon or Cadmium-Telluride in his eye that detect x-rays passing through a special lens called Kumakhov polycapillary focusing x-ray lens implanted in his eye.

The other possibility could be that x-rays get converted to normal light by a film of x-ray fluorescent material and then it is the normal work of the rods and cones like in case of the human eye.


Superman's eyes actually PROJECT X-rays; depending on how much is absorbed or reflected back at him allows him to see through solif objects.

Back in the day, Superman's "heat vision" was actually just a creative use of his X-ray vision -- he would project enough X-Rays to actually melt or destroy an object.

and finally my favorite:

In today's society, he probably couldn't use it with all the lazy people with lead in their asses! LOL

Of course we can't forget to see what wikipedia says about this understudied phenomenon:

The best known figures with "x-ray vision" are the fictional superhero Superman who once had a heat producing function before that power was separated as heat vision, and the protagonist of the 1963 film X (aka X: The Man with the X-Ray Eyes).

At least in the first Superman movie, Superman's X-ray vision could see through female character Lois Lane's clothing to see the color of her underwear. This implies it had nothing to do with actual X-rays, since color is a matter of spectral properties at optical frequencies.

In the movie Superman Returns, Superman uses the X-ray vision to see into the interior of Lois Lane's body in order to check for internal injuries.

Now that we have that all out of the way lets get onto some 'real' science...

Let's start with the basic human visual system. Light propagates through the air, being partially reflected by the objects that it encounters. This light reaches our eyes and is translated into chemical responses by the rods and cones in our retinas, and then travels through various sets of neurons where it is processed in different ways, giving rise to the experience of vision. So basically we need an information source and a processor. In the case of human vision this is light and the brain. In the case of superman this becomes more complicated.

There are three basic conditions that a superman x-ray system must meet to be plausible.

1. Transparency:

The rays must be such that all objects but lead are entirely or almost entirely transparent to them. Lead is always entirely opaque to the rays.

2. Color:

The rays and processor must result in Superman perceiving the same colors as would an Earthling viewing the scene in ordinary sunlight.

3. Exclusivity:

The rays must permit Superman, but not Earthling standing in line with the reflected rays, to see through normally opaque surfaces.

These conditions lead to two clear solutions.

The first solution:
Rays are emitted by Superman's eyes which penetrate objects and then return to his eyes.

- x-rays penetrate lead (perhaps superman uses a different energy wave?)
- The 'stopping problem.' Once the rays penetrate something why do they not continue on through the next object and the next and the next. If the rays do somehow stop/are lessened after penetrating the object how do they then get back to Superman in order for him to process the signal?
- To generate color the rays emitted by Superman's eyes have to be multifrequency so that they bounce off/are absorbed by different colors in the environment.

The second solution:
Two types of rays are emitted by superman, one to make objects transparent and the other to 'see'

- There is no evidence that a ray of this type could exist.
- The 'stopping problem' is still in effect.
- The transparency ray violates the exclusivity condition. If a ray makes things invisible then all the normal humans could see through walls as well (assuming superman shot his rays out for them). Then again if the rays made objects only transparent to a certain spatial frequency not available to human perception, lets say ultraviolet, or infrared. Then the transparency ray would not have to violate the exclusivity condition. But then color processing gets whacked.

The biggest problem of all for any theory of x-ray vision is as J.B. Pittenger says,

One fundamental problem with the plausibility of Supeman's x-ray vision lies in its need to make objects serve, at different times, as both media and things-to-be-seen. This places rather strong requirements on the nature of the rays or on the device that processes the rays.

So why did J.B. go to all this trouble of figuring out all the problems with Superman's vision?

The contrast between human vision and Superman's x-ray vision can be useful in helping students understand the importance to vision of the physical nature of light and its interaction with the air and objects in the environment.

Human vision has evolved to make use of several physical properties of 'visible' light: over short distances it passes largely unchanged through air, thus making air nearly invisible' it is reflected by most surfaces in the environment, thus allowing them to be visible' and the reflection is only partial, thus structuring the light so as to provide information to the perceiver.

If you're interested in reading the article you'll have to head over to your university library since the article is not yet available online. If you do manage to get a digital copy I would love a copy!

Pittenger, J.B. (1983). On the plausibility of Superman's x-ray vision. Perception, 12(5), 635-639. DOI: 10.1068/p120635


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An interesting side-note.

X-Ray vision may have doomed thousands of Americans to death in WWII. When Clark Kent went to join the Army following the bombing of Pearl Harbor, he was a little distracted and inadvertently read the eye chart in the next room. He was declared 4-F, but he did not feel bad because the American soldier was the "real Supermen." Yeah, it's a little too ubermensch for me, but it was, nonetheless, the Superman storyline at the time.

HJ (WWII, not Superman, buff)

Congratulations on The New Blog! I am sure it will be a lot of fun, and we all look forward to that.

My only concern is that we should all know that you have taken the proper steps to prevent Lex Luthor from reading this.

ps: How far away are we from me "testing" some of the "special specs" at a Victoria Secrets Fashion Show?

Superman's X-ray vision is indeed a nice thought-experiment for, say, a biology or psychology intro class (or physics, I suppose). For the present generation of students, another good choice is the "Animorphs" series of books, which were quite popular at about the time current students would have been reading them. Basically, the protagonists could morph into other animals, and would sense the world through the sensory systems those animals possessed. Increased UV or IR sensitivity, echolocation, and lateral line sense were all explored.

Such discussions (whether Superman or other) also allow a nice diversion into the lack of evidence for any form of "ESP energy", any organ to detect it, any brain pathways to process it...

Well, we know that there are animals right here on Earth that can visually process information in the near-infrared or near-ultraviolet range. It's not that hard to imagine a Kryptonian life-form with visual sensitivity through the X-ray and into the near-Gamma-ray end of the electromagnetic spectrum. Perhaps Krypton's famed yellow sun contributed to this evolutionary strategy.

I assume that, like radiation, there is some small amount of scattered background x-ray activity going on all around us all the time. Any organism capable of seeing in this spectrum would have developed some strategies for dealing with the prodigious amount of visual information coming into the brain for processing.

Perhaps x-ray vision is simply a matter of Superman changing his focus of attention. For example, imagine that you've dropped your car keys in a pile of leaves. You stop, and change your focus of attention to look for light reflecting off metal, or the contrast between the straight edge of your key and the organic shapes of the leaves.

It seems to me that when Superman uses his x-ray vision, he stops what he's doing and focuses his attention. This is what you would expect if he sees into the x-ray spectrum all the time, but his conscious brain generally disregards that information as noise.

Every so often, Superman "sees" waves outside the visibile electromagnetic spectrum, like radio waves, though it seems he has to "focus" on them. But what color are these waves? Does he see colors outside the ROY G BIV spectrum, and, if so, what would they look like; or does the ROY G BIV spectrum expand so that at one extreme he sees what we would recognize as red and at another what we would recognize as violet, but with finer distinctions all along the spectrum?

By CJColucci (not verified) on 03 Mar 2008 #permalink

Superman is from a different planet. Maybe his eyes work more like lobster eyes.

As an interesting aside, regarding the possibility of x-ray vision giving Lois radiation sickness: In the graphic novel Watchmen there was a story element in which it was implied that a super-powered character (Dr. Manhattan) was causing cancers in the people around him. It turned out to be a smear campaign, but it sure seemed plausible. All that radiation can't be good for you, can it? Maybe the Hulk's increased body size is really just tumours growing all over his body...

Heh -- the "color of her panties" issue, and some of the others, only make sense if you demand that something called "X-ray vision" has to use actual X-rays. Most of Superman's powers are magic with a veneer of technobabble -- X-ray vision is just clairvoyance, with the "mandatory weakness" that lead blocks the image.

On the other hand, if you want a 3-D sense that can look though things (and you get to wave your hands vigorously) you could postulate that he can see neutrinos, with arbitrarily sensitive imaging and focusing. That wouldn't get color, but he'd be able to look through anything.

By David Harmon (not verified) on 03 Mar 2008 #permalink

Google "backscatter x-ray imaging" and "t-rays" for some possibilities.

Hi Steve,

I tend to agree with comment #6.
Vision is a receptive not transmitive phenomenon.
The electromagenetic spectrum separating light from Xray is probably to great for any organism to have both.
There are organisms that appear to have both light and UV [birds] or light and IR [vipers and boas].
There are devices that can assist human detection of both IR and UV.

Since seeing the movie 'Jumper', I no longer envy superman's flying ability.
Self-teleportation would be an astonishing superpower.

Hi there i don't think its possible to see in to the body with your own eye's
But i think everyones missing the point .Im a reiki healer and not a big head and i can see into the body with my third eye just like a m.r.i scan can. I can see bones brain muscle and pain and decease and
the energy of the body the aura and thats the truth believe me or not its up to you

By clinton york (not verified) on 21 Nov 2011 #permalink