Science, Pseudoscience, X-Rays and Superman
June 10, 2017
by William P. Meyers

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The discovery of X-rays by Wilhelm Roentgen

Everyone knows who Superman is, and that he has x-ray vision among his superpowers. But few people can name the discoverer of x-rays, Wilhelm Conrad Roentgen (or Röntgen). We live in an bipolar era where there is a vast science establishment, and science feeds and clothes the world, but ignorance is the norm, and even drives our politics.

The word "discovery," even narrowed to the field of science, actually has a broad set of meanings. The particulars are important. And choosing the wrong particulars within the discovery process can produce pseudoscience rather than science. The discovery of x-rays illuminates these issues.

Before x-rays there were cathode tubes, with their attendant cathode rays. These began as gas-filled tubes through which a current was forced, probably by Michael Faraday in 1838. Johann Geisler, a glassblower and experimenter, invented a way to create a good vacuum in a tube, the mercury pump, in the mid 1850s. Run a sufficient current through a Geisler vacuum tube, and you got pretty colored lights. These predecessors of neon lights became common display items in Germany in the late 1850s.

Add an induction coil to spike the voltage of your batteries (this was before the commercial availability of electricity), and you have a cathode tube, which generated cathode rays, which would later be identified as naked electrons, the workhorse of our modern information-driven society. A generation ago the cathode tube was familiar to everyone in the form of a TV set, or an old-fashioned computer monitor.

Cathode rays propagate well in vacuums (or near-vacuums), but they fade quickly in air as the electrons collide with air molecules. Philipp Lenard had found a method to get cathode rays to shine a short distance beyond the walls of a vacuum tube. Roentgen was basically repeating Lenard's experiment.

The difference was that Lenard's tube was encased with metal. Roentgen's was glass, but covered with thin black cardboard. Roentgen found that a fluorescent screen outside the tube (and the black cardboard) glowed each time an electric discharge was applied to the tube.

Not only did these new rays propagate much further than cathode rays, they also affected photographic paper. Soon Roentgen was taking pictures of the shadows of bones within the human hand. Roentgen's interest had been in phosphorescence and fluorescence. If he had clad his apparatus in metal, like Lenard did, he probably would not have noticed the x-rays, which would have been trapped inside the metal along with the cathode rays.

This was in November 1895. And then x-rays were off to the races. They were not hard to produce, once Roentgen showed the way. But there was still plenty of mystery involved. Roentgen, for instance, thought he had discovered an entirely new form of radiation, not related to either light or cathode rays. He thought x-rays were a form of longitudinal wave. He thought they moved faster than light, which is a traverse wave. It took more than a few years to sort that out.

For a long time no one could make x-rays refract, which was a fact in favor of the longitudinal wave camp. Also, they did not seem to be polarized, again in favor of the longitudinal ray hypothesis. The issue was not settled until 1912, when crystals were used to refract x-rays. They were simply high-energy, high frequency rays beyond the previously known spectrum. The cathode rays, which are electrons, are stopped suddenly by the anode, and the energy of deceleration is released as a high-energy photon.

So what? The utility of x-rays is well established. But the harder any science is to understand, the more likely it will get used by pseudoscientists to mislead or even defraud the public. Often the pseudoscientist and scientist (or medical doctor) are the same person. The authority of the scientist makes the public more willing to enlist pseudoscience.

X-rays were one of many scientific phenomena that were exploited by pseudoscientists. The worst charlatans promoted them as healing rays, but the most widespread damage resulted from their actual utility. Everyone wanted magical x-rays, and doctors obliged. It took a while to realize that x-rays can cause damage to living organisms, and to set standards for safely taking x-rays of humans.

Then came Superman. The first Superman comics appeared in print in 1938. Eventually x-ray vision was added to his list of powers, but in a pseudoscientific way. To see through an object with x-rays, one needs the object to be between oneself and the x-ray source. In the comic, superman appears to be the source.

Physics, the domain of x-rays, electrons, and radioactivity, is in many ways the simplest of the sciences. Biology is much more complicated. There are tens of thousands of types of molecules in a human cell, for instance. When there are a lot of variables in a situation, it is difficult to sort out cause and effect. A pain in the foot may be from an injury to the foot, or from an injury to the back, or from a problem in the brain. The interactions of DNA and the body's cells and organs are marvelously complicated, and still being studied.

That is why science still has trouble conquering cancer. Health, medicine, and nutrition are particularly prone to pseudoscience. It is hard to isolate a single variable in a group of humans. Dietary studies are particularly prone to mishaps and misinterpretation. Notably, long term studies usually depend on the subjects accurately reporting what they eat and drink over a long period of years. One investigator decided to test the truthfulness of his subjects (by searching their garbage) and found they drank far more beer than they reported.

Then there is subset analysis. I had better save that subject, and its relations to pseudoscience, for another post. But let me just say: seeing which people live longest in which localities, and then declaring whatever diet they happen to have to be the cause of longevity, is probably an example of erroneous subset analysis.

Chemotherapy for cancer patients sometimes kills the patients before the actual cancer would have. Biological science is messy. So it should not be surprising that pseudoscience can persist for long periods of time when it applies to human health.

Source for physics history: Inward Bound by Abraham Pais, Oxford University Press, 1986