This article briefly discusses the various forms of radiation, and radiation-related dangers affecting our lives. I wrote it for my two teenage boys Roland and Dorian.
What is radiation?
‘Radiation’ is parented to the English word ‘ray.’ It describes a flux of energy through space, endowed with the following attributes:
- A vector (direction) of movement.
- Charge (positive, negative, or neutral).
- Energy being expressed by wavelength, frequency, or mass.
The most common form of radiation experienced day by day is sunlight, a spectrum of radiation that appears to the eye (and brain) in the colors of the rainbow, ranging from red (long-wave) to violet (short-wave). The bandwidth of the sunlight, however, is much larger than our eye can detect, and process: infrared waves feel warm and pleasant, and ultra-violet rays burn our skin at the beach. Other waves of longer wavelength are used to transmit signals such as radar, radio or TV. There are, however, many other invisible forms of high-energy radiation:
- Cosmic radiation rains down from the sky. Its main source is the sun that continuously expels a stream of energy called solar wind. Other radiation stems from the inner part of the solar system, and the universe in general. These radiations are largely taken care of by a (weakening) earth’s magnetic field, and an (increasingly dysfunctional) ozonosphere.
- Similar radiation emanates also from the ground, caused by naturally occurring nuclear decay. These radiations are called Alpha, Beta and Gamma, and are sourced from radioactive metals such as Uranium, Thorium and Potassium 40.
- As known to everybody, there is also human-made Alpha, Beta and Gamma radiation. These originate from (faulty) nuclear reactors, (aging) nuclear recycling plants, nuclear weapons facilities, and waste dumps contaminated with nuclear waste from hospitals.
- Another source of high-energy radiation originates from X-ray devices that are used for medical body imaging, material integrity (steel), or import/export control (containers etc).
How is ‘nuclear’ radiation being measured?
The most common devices to measure ‘radioactivity’ are called ‘Geiger Counter’ or ‘Scintilometer.’
They contain a tube of vacuum, with an electrical circuit on either side of the tube. An incoming, high-energy particle causes an electrical field in the tube, and an electrical impulse occurs.
With the help of these detectors one can measure anomalous levels of radioactivity. To know which level can be considered abnormally high or not, one needs to understand the common level of the area, which is called ‘Background Radiation.’
The natural ‘Background Radiation’ of an area appears very constant over time, and depends on the mineral composition of the ground, and its elevation above sea level. Rocks such as granite or volcanic rocks usually offer higher levels of radiation compared to limestone, or clean sandstone. The level of radiation also increases with elevation: the thinner the atmosphere above our heads, the more cosmic radiation energy hits the ground. Most times one can only measure the total (combined earth and cosmic) radiation. Only in deep tunnels or mine shafts the earth component can be determined with a degree of certainty.
Just before the Tchernobyl disaster of 1986, I had measured ‘Background Radiation’ levels in Southern Bavaria for my geologic PHD. The background level oscillated at 200 millirem/year, which is a measurement of cumulative radiation.
After the first contaminated rains, however, the radiation level on my garden lawn shot up to 1600 millirem/y. Over the next coming days, the level on the grassland dropped to 800, then to 600 millirem/y. I wondered what was going on, and dug a ditch in the garden. Over the coming days, I detected a front of relatively high radiation, sinking into the ground with a speed of several inch/day. That year the Government issued a warning about possible contamination levels in forest mushrooms…
Health risks related to radioactivity.
I won’t discuss here the brutal effects of weapons-of-mass-destruction- caused by massive X-ray bombardment of 1 rem/day or more. But why does radiation cause health risks? Studies have shown that high-energy particles destroy or damage the organic molecules in our body. In particular, the biochemical ‘software’ in our cells, the DNA, is under fire and becomes dysfunctional. Although the body struggles to repair corrupted DNA and damaged cells, such repair processes are only successful if the damage remains limited. One could compare radiation-induced damage to a corrupted Windows program on a PC: a few errors can be fixed, but too many errors cause the program to crash.
Space research has possibly shed some light, how much ‘cosmic’ radiation our body can endure. The continuous damage caused by cosmic rays in the bodies of astronauts is already so strong, that our human body-repair-system appears fully occupied. This leads to the question, if extended space traveling is actually possible.
Among the different classes of dangerous radiation, Gamma rays (almost like x-rays) are seen as the most dangerous form: Gamma rays can shoot through metal (but not Osmium, Lead, Uranium, Barium), traverse a brick wall and definitely our body. The slower Alpha (positive, proton) and Beta (negative, electron) particle streams are stopped already by protective clothing. Alpha-emitter-contaminated food, however, can do havoc in our body, causing cancer depending on the level of contamination.
Normal earth-dwelling citizens are not particularly endangered by radiation. As always, however, there are a few noteworthy exceptions:
- Living in an area where the radioactive gas Radon occurs.
- Frequent flying, at high altitude, and in the polar region. Today’s airplanes are devoid of any (heavy) coating that could protect the (light metal-and-plastic-component) aircraft cabin from cosmic radiation.
- Radiation building up around cellular phones and satellite phones/antennas, and grilling our brain cells.
- Radiation from rogue X-ray machines, or poorly calibrated ones. Let’s hope our hospital got a good calibration engineer.
- Radiation emitted from ceiling smoke detectors using a radioactive cell; these devices are common in offices and hotel rooms. Don’t spend your life sitting below one of those detectors.
Because we cannot see or feel radioactivity, it causes fear and even paranoia. This said, common radioactive threats to our health appear minor and can certainly be managed. Strangely enough the biggest radiation exposure may be triggered by our cellular phone, or a good sun-burn down at the beach.
© 2005 by Franz L Kessler