Radioactivity

To better understand the concept of "radioactivity" - an overused and frequently misused term - it might be helpful to briefly step away from the world of the Seventh Art, dust off those physics textbooks and review a few fundamental concepts about radioactivity...

First things first: "electromagnetic radiation" refers to the synchronized propagation of electrical and magnetic fields through space. This electromagnetic wave travels at the speed of light (~3x10^8 m/s in a vacuum), perpendicular to the direction of energy and wave propagation (and the two fields are in turn perpendicular to each other). The distribution of the various possible frequencies of electromagnetic radiation collectively make up what's called the "electromagnetic spectrum".

This Tag focuses mainly on ionizing radiation, that is, radiation characterized by frequencies high enough to ionize (detach electrons from) atoms or molecules that it comes into contact with. In addition to the electromagnetic waves located in the higher energy portion of the electromagnetic spectrum (ultraviolet radiation, X-rays, gamma rays), ionizing radiation can also consist of subatomic particles or ions that move at high speeds (these subatomic particles include alpha particles, beta particles, and neutrons). Basically then, radioactivity (or "radioactive decay") consists of a collection of physical phenomena by which some nuclei which are not perfectly balanced achieve greater stability by releasing ionizing radiation. In other words, we're talking about a transformative atomic process whose high energy emissions are capable of causing serious biological damage (altering nucleic acids, destroying bonds between molecules, etc.).

The first scientific research on radioactivity was conducted towards the end of the 19th century, but a full awareness of its dangerous potential lagged for decades. Case in point are X-rays, accidentally discovered by German physicist Wilhelm Conrad Röntgen in 1895. Although reports of hair loss, dry skin, and burns emerged shortly thereafter, X-rays captured the public imagination and their risks were simply ignored as this fascinating new technology was used in irresponsible ways. For example, "fluoroscopy" (moving X-ray pictures) became a circus and carnival sideshow attraction, allowing patrons to view their own skeletons and even receive pictures of their bony hands wearing silhouetted jewelry. In the 1920s, X-rays found another questionable use, as machines called "pedoscopes" were introduced to shoe stores and heralded as "providing a more scientific method of fitting shoes". Tens of thousands of such shoe-fitting fluoroscopes were operating (with little or no regulation or concern for safety) in the US and UK by the early 1950s (some continued in use as late as the 1970s).

But it was during the 1920s that misconceptions (and willful ignorance) about the dangers of radioactivity assumed truly colossal (and tragic) proportions. The popular conviction at the time was that slight exposure to a radioactive element was a stimulant affording certain health benefits.(+) Consequently, the consumer market was flooded with products exalting the virtues of radium (and other radioactive materials). Examples include "Radithor" (a brand of "Certified Radioactive Water"), which supposedly contained miniscule amounts of radium isotopes; "Doramad" toothpaste (containing radioactive thorium), which sold in Germany until 1945; and a long list of assorted cosmetics, medicines, and supplements... all of which sadly toxic.

A string of tragic and high-profile events - such as the dramatic story of the "Radium Girls" and the horrific death of golfer Eben Byers - would bring about a slow but inexorable change in the public's attitude regarding radioactivity. With the dawn of the atomic age and images of two Japanese cities practically wiped off the face of the earth by unprecedented weapons of war, fears regarding nuclear power and ionizing radiation finally took hold in popular opinion.(+)

Sci-fi movies of the 1950s voiced the anxieties of the atomic era in tales filled with mutant beasts and Geiger counters. And although settings and scenarios would evolve over the years, an obsession with radioactivity - and its mutagenic effects - would become a cinematic staple for decades to come, from films by Ishirō Honda and his Japanese colleagues to post-apocalyptic works of the 1970s and '80s.