But since the wall hasn't really dissolved, how exactly is he 'seeing'? The underlying assumption is that the x-rays he shot through the wall are reflected off of the people in the building and head back to his eyes.

So how does Superman view an x-ray image? In the classic comic book scene, Superman shoots x-rays from his eyes at the wall, and then the wall sort-of dissolves and he sees what's happening behind it. In the case of the airport baggage screener, the resulting image is then digitally displayed on a screen for the surly airport security worker to view. The x-rays are absorbed to a greater or lesser extent depending on the nature of the material. In most applications utilizing x-rays, such as the baggage screening machines at the airport, the x-rays pass through a sample and are detected on the other side by a specialized camera or photographic plate. Next, there are problems with reflection and detection. That is, they are as wide as the distance between molecules in a glass of water. X-rays have wavelengths on the order of Angstroms (10 -10 meters). There's a good reason they drape that lead apron over you and then leave the room while you are being irradiated. The x-rays used at the dentist and doctor's office are used very sparingly, and even so it still isn't a good idea to get too much exposure. Sorry, Superman! Maybe using x-rays to see through the clothing of your beloved isn't such a great idea. The result? Cell growth out of control (i.e. Radicals in turn wreak havoc on your DNA. įirst, x-rays happen to be at just the right frequency to a) get through your skin, and b) break the oxygen-hydrogen bonds in water and produce radicals in your body. But they are all traveling electric and magnetic fields they are all fundamentally the same 'stuff'. Decrease that a couple more orders of magnitude and you have x-rays. Go all the way down to hundreds of nanometers (nine orders of magnitude smaller than a meter) and you have visible light. Change that wavelength to centimeters and you've got microwaves. The wavelength of radio waves is on the order of tens of meters. The key difference between all these different manifestations of light is the wavelength, or the distance between the tips of the waves. They can be thought of as waves in the same way that you think of waves on the ocean. They are all composed of electromagnetic fields-that is to say, a combination of both electric and magnetic fields-traveling through a medium (or through vacuum). In fact, x-rays, visible light, radio waves, microwaves, and gamma rays are all very similar. X-rays are more similar to visible light than one might think. That is, their wavelengths are about as big as a house. Radio waves have wavelengths on the order of meters. After noticing that objects placed in the path of the x-rays showed some amount of transparency as seen by the images on a photographic plate, Roentgen shot his poor wife's hand with an unhealthy dose of x-rays, capturing that famous first x-ray photograph of the bones of a human hand. The discovery of x-rays is attributed to Wilhelm Roentgen, who produced them quite by accident in 1895 while working with electrical discharges in vacuum tubes.

(Unlike, say, the ability to fly with a red cape.) Today we are familiar with the x-ray detectors used in airports, so x-rays are no longer considered exotic, and the possibility of x-ray vision does not seem so far-fetched. Why did Superman's original writers choose 'x-ray vision' as one of their superhero's powers? My guess is that x-rays were considered exotic and powerful during the late 1930s (when Superman first appeared), and the writers were inspired by the ability of the doctor's x-ray photograph to see though the soft tissue of the body to the teeth and bones. Wavelength is measured as the distance between peaks of a wave.

When did superman get xray vision