Strange Glow

The Story of Radiation

Timothy J. Jorgensen

• Publisher: Princeton University Press
• Year: 2016
• ISBN:
  9781400880522
• Topic: Technology & Engineering
• Subtopic: Applied Sciences
• Index: Technology & Engineering

The fascinating science and history of radiation More than ever before, radiation is a part of our modern daily lives. We own radiation-emitting phones, regularly get diagnostic x-rays, such as mammograms, and submit to full-body security scans at airports. We worry and debate about the proliferation of nuclear weapons and the safety of nuclear power plants. But how much do we really know about radiation? And what are its actual dangers? An accessible blend of narrative history and science, Strange Glow describes mankind's extraordinary, thorny relationship with radiation, including the hard-won lessons of how radiation helps and harms our health. Timothy Jorgensen explores how our knowledge of and experiences with radiation in the last century can lead us to smarter personal decisions about radiation exposures today.Jorgensen introduces key figures in the story of radiation—from Wilhelm Roentgen, the discoverer of x-rays, and pioneering radioactivity researchers Marie and Pierre Curie, to Thomas Edison and the victims of the recent Fukushima Daiichi nuclear power plant accident. Tracing the most important events in the evolution of radiation, Jorgensen explains exactly what radiation is, how it produces certain health consequences, and how we can protect ourselves from harm. He also considers a range of practical scenarios such as the risks of radon in our basements, radiation levels in the fish we eat, questions about cell-phone use, and radiation's link to cancer. Jorgensen empowers us to make informed choices while offering a clearer understanding of broader societal issues.Investigating radiation's benefits and risks, Strange Glow takes a remarkable look at how, for better or worse, radiation has transformed our society.

CHAPTER 1

NUCLEAR JAGUARS

In the dark, all cats are jaguars.

—Anonymous Proverb

As a rule, men worry more about what they can’t see than about what they can.

—Julius Caesar

The common denominator of most radiation exposure scenarios is fear. Just mention the word radiation, and you instill fear—a perfectly understandable response given the images of mushroom clouds and cancerous tumors that immediately come to mind. Those images would justifiably cause anyone to be anxious. Nevertheless, some people have also become highly afraid of diagnostic x-rays, luggage scanners, cell phones, and microwave ovens. This extreme level of anxiety is unwarranted, and potentially dangerous.

When people are fearful, they tend to exaggerate risk. Research has shown that people’s perception of risk is tightly linked to their fear level.¹ They tend to overestimate the risk of hazards that they fear, while underestimating the risk of hazards they identify as being less scary. Often their risk perception has little to do with the facts, and the facts might not even be of interest to them. For example, many Americans are terrified of black widow spiders, which are found throughout the United States. They are uninterested in the reality that fewer than two people die from black widow bites each year, while over 1,000 people suffer serious illness and death annually from mosquito bites. Mosquitoes are just too commonplace to worry about. Likewise, the risk of commercial airplane crashes is tiny compared to motorcycle crashes, but many a biker is afraid to fly.

The point is that risk perception drives our decision making, and these perceptions often do not correspond to the real risk levels, because irrational fear is taking our brains hostage. When irrational fear enters the picture, it is difficult to objectively weigh risks. Ironically, health decisions driven by fear may actually cause us to make choices that increase, rather than decrease, our risks.

Fear of radiation is particularly problematic considering the trend in radiation exposures. Since 1980, the background radiation exposure level for Americans has doubled, and is likely to continue to climb.² Similar patterns are occurring in all of the developed and developing countries. This increase in background radiation is almost entirely due to the expanding use of radiation procedures in medicine. The benefits of diagnostic radiology in identifying disease and monitoring treatment progress have been significant; however, radiation has also been overused in many circumstances, conveying little or no benefits to patients while still subjecting them to increased risks. Furthermore, medical radiation is not distributed evenly across the population. While some people are getting no medical radiation exposure at all, others are receiving substantial doses. Under such circumstances, the “average” background radiation level means little to the individual. People need to be aware of their personal radiation exposures and weigh the risks and benefits before agreeing to subject themselves to medical radiation procedures.

In addition to the medical exposures, people receive radiation doses from a variety of consumer products, commercial radiation activities, and natural radioactivity sources in our environment. Some of these exposures are low level and low risk, while others can be at a high level and potentially hazardous. People need to be aware of these different radiation exposure hazards, and protect themselves when necessary.

In the pages that follow, we will explore the story of radiation with a specific focus on health. We will investigate what we know about radiation, and how we know it. We will weigh the risks and the benefits and characterize the uncertainties. We will identify the information needed to make rational health decisions about radiation, and we will uncover the limits of that information.

Since we typically cannot see radiation, we tend to be both intrigued by and afraid of it. We have endowed radiation with magical transformative powers that produce the superheroes of our comic books, such as the Incredible Hulk (exposed to gamma rays), Spider-Man (bitten by a radioactive spider), and the Teenage Mutant Ninja Turtles (overexposure to radiation). Yet, even superheroes are ambivalent about radiation. Superman is thankful for his x-ray vision, but scared to death of kryptonite (a fictional radioactive element).

In the end, we don’t know what to think. Nevertheless, we have practical decisions facing us at the individual, community, state, national, and international levels. Questions range from whether one should agree to have a dental x-ray today, to whether more nuclear power plants should be built for energy needs 20 years from now. Such questions must be answered both individually and collectively, and answered now. We cannot postpone our decisions until more data are accumulated or more research is done, and we cannot relegate the responsibility to scientists or politicians. These decisions must be made by the electorate and the stakeholders; that is, by every person in our society.

The problem is that there are different types of radiation, and they are not all equally dangerous. Regrettably, most types are invisible, and we tend to fear things that we cannot see. Furthermore, we’ve lumped the invisible ones all together as equally hazardous. They are not, and we need to be able to tell the difference. All cats are not jaguars.

Which types of radiation should be feared? People must decide that for themselves. But that decision needs to be based on the facts. Although some things remain unknown, obscure, or uncertain, we cannot pretend that we know nothing about radiation and its health effects. The scientific and medical communities know a great deal about the effects of exposure after more than a century of experience with radiation. In fact, we know more about radiation than any other environmental hazard.

Although seeing is believing, not seeing shouldn’t mean not believing. This is particularly true for radiation, since most forms cannot be seen directly. There is, however, one type of radiation that can be seen. This is light. Fortunately, light possesses many of the same properties as the invisible types of radiation. So we can overcome at least one barrier to understanding radiation by starting with the kind that we all can see, and then moving on from there to the invisible types that lurk ominously in the dark. We’ll begin our radiation journey by looking under the lamppost, where reality is revealed … and where jaguars dare not roam.

PART ONE

RADIATION 101: THE BASICS

CHAPTER 2

NOW YOU SEE IT: RADIATION REVEALED

A man should learn to detect and watch that gleam of light which flashes across his mind from within.

—Ralph Waldo Emerson

CHASING RAINBOWS

Radiation is simply energy on the move, be it through solid matter or free space. For the most part, it is invisible to us and can only be detected with instruments. But there is one type of radiation that can be seen with the naked eye. This visible radiation is called light.

Who isn’t fascinated by light? Whether as sunrises, fireworks, or lasers, light mesmerizes us because we can see it. Most of us have at least a rudimentary understanding of the physical principles of light because we have practical experience with it. We know that light casts shadows, bounces off mirrors, and comes in different colors. Other types of radiation have similar properties, but we don’t see them. They exist apart from our everyday experience, and thus seem mysterious—ever present but never seen. Yet, the physical properties of light have much in common with these other types of radiation. Hence, by examining what’s going on with light, we can actually get a glimpse of what is happening with its unseen cousins.

Light is just a tiny part of the world of radiation, but a very important part. We would be remiss if we neglected light; the story of radiation is strongly tied to its story. So as not to be remiss, let’s briefly review what we know about light.

Throughout prehistory, light came almost exclusively from the sun and fire. From these observations of light, primitive humans deduced that the sun was a massive ball of fire. This deduction, which was likely one of mankind’s first scientific conclusions, turned out to be absolutely correct.

Fire produces both heat and light, but warm things aren’t always bright (e.g., body heat), and bright things aren’t always warm (e.g., fireflies). These facts suggest that heat and light, though often found together and in some ways related, are fundamentally different phenomena that can be uncoupled and studied separately.

One of the things people noticed about light was that it could bend when it moved through water. Consider the appearance of an object protruding through the surface of clear water. The object seems to be displaced. That is, the position where the object, such as a stick, appears to enter the air seems to be different from where it exits the water; and thus it seems to be broken. (We all see this when we look at a drinking straw in a glass of water.) This occurs because light passing through liquid bends. The part of the object in the water is actually in a different position than where it appears to be to the human eye.

This property of light (called refraction) had very practical implications even for primitive peoples. For example, archers hunting for fish with a bow and arrow knew that if they aimed directly at the fish in the water they would always miss. Rather, if they aimed slightly below the fish, that fish would be dinner. The same thing did not work for prey in the air. Shooting arrows under birds did nothing but scare them.

Likewise, refraction is responsible for the magnification produced by droplets of water on leaves or other surfaces. Following the discovery of clear glass,¹ the magnification of water droplets could be simulated (and made permanent) by using droplets of glass. Through forming the clear glass droplets into different shapes, their magnification properties could be altered at will, and a variety of these droplets (i.e., lenses) could be made and used individually or in combination to produce telescopes and other visual instruments. Thus was born the field of optics—the branch of physics that studies the properties of light and its interactions with matter—and the path was made clear for research into the properties of light, the only type of radiation known at that time.

Before that falling apple and gravity got his attention, the first scientific passion of Isaac Newton (1643–1727) was optics.² In his laboratory, Newton made a number of novel observations about the properties of light. For example, he discovered that white light is composed of colored light blended together.³ As he demonstrated, white light can be separated into its colored components with the use of a glass prism. This occurs by virtue of a light-bending effect known as dispersive refraction, whereby various wavelengths of light (i.e., different colors) bend slightly differently when passing through the prism; and thus the wavelengths separate from one another.

Newton used manmade prisms as light-bending tools for many of his optical experiments and demonstrations on the properties of light. However, the most dramatic evidence of a prism effect is the natural separation of sunlight into the colors of the rainbow by a large volume of water droplets, as can be seen in the sky following a storm. Unfortunately, Newton’s experiments with light rays were limited by his senses. He couldn’t measure what his eyes couldn’t see. He didn’t know that beyond those colored rays there was a universe of invisible rays that he could not sense or detect.

Later, scientists were fascinated by another phenomenon often associated with storms. This was electricity. Ever since the time of the apocryphal story of Benjamin Franklin flying a kite in the lightning storm, the public had been generally aware of the existence of electricity and what it could do. Besides killing people and burning down barns, in weaker forms it could produce sparks and even make the hair on one’s head stand up. Electricity could also be generated simply by rubbing two different materials together (i.e., static electricity). So one didn’t need to wait for a storm in order to play with electricity. In fact, small static-electricity machines were highly popular parlor toys for the aristocrats of Franklin’s day.

Investigations of light and electricity ran in parallel paths. Yet, it wasn’t until the late 1800s that the connection between light and electricity would begin to be understood and then developed into practical uses for the general public.

A BRIGHT IDEA

Contrary to common wisdom, Thomas Alva Edison (1846–1931) did not invent the first electric light bulb. That had been invented by Humphry Davy (1778–1829) in approximately 1805, and was called an arc lamp. Arc lamps produce light in a glass bulb in the form of intense brilliant white sparks that are produced in rapid succession. Arc lamps were suitable for outside illumination from tall lampposts, and such lampposts were in common use in public areas of major cities in Edison’s day. But the arc lamp was simply too bright for use in the home.⁴ A different approach would be needed to bring electric lighting into homes.

Edison knew, as did others, that running electricity through a variety of materials could make those materials glow—a process called incandescence—thereby producing a light source that could be used as an alternative to candles and natural gas lamps. The problem was that the glowing material (the filament) would degrade after a short while, making its use as a household lighting device impractical. Not knowing any of the physical principles by which electricity destroyed the filament, Edison simply tried every material he could to see if one would glow brightly, yet resist burning out. After trying 1,600 different materials, including cotton and turtle shell, he happened upon carbonized bamboo, which turned out to be the filament of choice (to the joy of turtles everywhere).⁵ When used in an air-evacuated bulb (i.e., a vacuum tube), the carbonized bamboo outshone and lasted much longer than any of the other tested filaments. Edison had his light bulb. Although tungsten soon replaced carbonized bamboo in home light bulbs, illumination by incandescence became the predominant mode of interior lighting for many decades to follow.

Despite its potential for lighting homes, the electricity that powered light bulbs was initially looked upon with great fear and suspicion by the public. And the public had good reason to be wary. Newspaper reports of people being electrocuted were common. Pedestrians were, understandably, frightened by the spider webs of telegraph ...