(Now that I've finished writing and proof-read this, I've considered changing the title to "Abandon hope, all ye who enter here.")
Yeah, you read that right. I still feel like crap and am working on Stealth Projects and spinning, so you're stuck with another of my topics from out of left field. In this case, the husbeast (who inspects nuclear reactors) and I (who lives with him and wonders just how dangerous his job is) have said for years we wished more average citizens understood the basics of radiation. Thanks to the media and some health care providers, people hear the word 'radiation' and their first response is, 'oh my god I'm gonna die'. And, well, what you should really be asking is 'what kind of radiation, and how much?' The answer is long, but I'm gonna try to keep it as brief as possible, and maybe entertaining into the bargain. Basically, we're gonna talk 'what kinds' and then get into the really annoying 'measurements' aspect. Proof reading this later, I've realized, 'what kinds' is taking forever, so I'm gonna do 'measurements and when to panic' tomorrow. 'Cause I'll probably still have a migraine. Plus, I think I need the husbeast to give this a proof-read, just to make sure I got the details right.
First, let us review. (Some of this should be familiar to long-term readers from my previous opus on the EM spectrum and visible light and color and reflecting spectra. This time we're branching out into more wavelengths.) So. The Electro-Magnetic Spectrum.
(I've got a really disturbing number of EM spectrum illustrations on my hard drive. As with most others, this one is from Wiki Commons.) As you see from the above chart, visible light is only a small part of a huge band of wavelengths; they go from low frequency (think sound waves) to high. The low-frequency stuff can mess you up, but generally it takes a good long time and (if you ask me) scientists really aren't quite sure what its effect on the body is. That "static field" over there at the far left can be, among other things, the magnetic field we're stuck into when we have an MRI done. I'm not saying an MRI is dangerous. I'm saying that if we lived inside one for two or three decades, it's likely something weird would happen and science has yet to figure out what. I doubt it's a priority. Likewise, the effect of fields created by high-voltage power lines is hotly debated, and research continues. Microwaves WILL heat your skin and burn you, as will the infra-red of heat lamps, salamanders (those super-broilers in restaurants) and, haha, sunlight. While all of these wavelengths will mess with you to some degree or other, their effects are pretty direct, so far as science has figured out so far.
Then there's visible light. We've discussed that before. Again, I doubt enough research has been done on exactly how visible light effects us. But I will say, as someone totally photosensitive who gets migraines, I'm not convinced it's entirely UV rays that causes me to shriek and put on sunglasses. But, by most analyses, visible light is considered harmless. (Though there have been warnings these last few years about the super-bright visible light spectrum produced by high speed photocopiers.)
All this is radiation, okay? The whole spectrum. The stuff we've discussed, including the visible light. All radiation. But it's rather run of the mill. We literally see it and live with it every day. We're getting to the radiation you need to freak out about, maybe.
Ionizing radiation is the stuff that damages your DNA and in some cases will literally knock bits off the atoms that make you up. Which, obviously, is really bad. The shift in the spectrum from 'regular' radiation to ionizing radiation happens in the UV (ultra-violet) band. Yes. The UV band that causes skin damage and cataracts that everyone has suddenly discovered in the last few years is bad. It's separated into UV-A, UV-B, and UV-C, and there is, as always, debate about which one causes the most damage. But you know how welders wear goggles to protect their eyes? It's UV light they're protecting themselves from. Every sunburn you've ever had was caused, mostly, but UV light; we've found in recent years that sunburns can trigger skin cancer, ultimately because UV light is ionizing radiation that can cause DNA mutation. Granted, it's mild mutation, often we never notice it, but it happens. (Notice tanning beds lurk in this portion of the spectra? So does sunbathing. I'm not sayin', I'm just sayin'.)
FYI, genetic mutation never turns you into one of the X Men. Which sucks ass because I'd love some super powers, but instead of the Power of Laundry I'm stuck with no wisdom teeth, good bones, and freaky retinas. Not enough for Xavier's School for Gifted Youngsters (every discussion of radiation needs a link to Marvel Comics). Usually, radiation damage causes nothing, or health problems of varying degrees of seriousness. Occasionally, one of those freak mutations causes evolution.
So, where were we? Oh, right. Ionizing radiation. After the UV portion of the spectrum, it gets kinda freaky, and we're into the realm of 'freak out' where the spectra lurk that people associate with the word 'radiation'. This doesn't mean you SHOULD freak out, because a lot has to do with dose. Most people don't know it, but two-thirds to three-quarters of our lifetime radiation exposure comes from the sun, earth, and other natural sources like radon gas. While it's not GOOD for us, the human body evolved soaking up a regular dose of all kinds of radiation, and so long as we don't up the dose significantly, our bodies will keep on keeping on. They're used to it. It's what they do.
X rays are next, and we all know those from breaking our arms or skulls or whatever. Yes, x rays are a kind of light. When we get an x ray, basically we're having our picture taken with a special kind of light; that x ray machine is just a super-fancy camera with a hell of a flash bulb. Before anyone thinks they're going to die of an x ray, guess again; unless you're an x ray tech, the vast majority of your x ray exposure comes from sunlight. Mostly x rays cause DNA damage, like UV rays. However there's some overlap in the spectrum between x rays and gamma rays.
I gotta wrap this up before one of you comes over here and kills me.
Lastly in the spectrum comes gamma rays, particle radiation, and cosmic rays. There are detailed, complex definitions for the different kinds, but I'm lumping them all together because their effect is the same in the human body and if I start on sub-atomic particles and decay rates and electron vs. neutron radiation one of you will stab me to death with a knitting needle.
These are the wavelengths that knock bits of your atoms off and cause most of the really horrifying damage that makes all of us freak out (including me). The kids who got stuck cleaning up Chernobyl died of this high-end gamma and particle radiation; other types of radiation exposure probably would have killed them too, but the gamma rays and particle radiation killed them first. Even at the unholy doses they received it took them a week or two to die; the movies where people are exposed to radiation and immediately keel over are just that - movies. Ditto for stuff glowing in the dark. Incidentally, the Chernobyl workers are thought to have died not so much from the radiation zooming around in the air, but from the radioactive particles of soot that they INHALED during the fire. Generally, external exposure is not nearly so serious as internal contamination caused by inhalation or eating contaminated food. Generally.
And, all right, I'm indulging in the tech stuff. There's also alpha and beta particle radiation, which act something like gamma but are more easily blocked; alpha radiation will be stopped by your clothing. Alpha and beta are both used medicinally quite a lot; a lot more than gamma, though it is used too. When I had a bone scan, I was given an alpha-particle emitting isotope that settled in my bones that they then took pictures of with very sensitive radiation detectors. That's how bone scans work. Kinda cool, huh? All particle radiation is caused by just that - actual bits of atoms. For alpha particles it's two neutrons and two protons. For beta particles it's electrons and positrons. They come from atoms that are so unstable they literally can't hang on to all their bits, and they just fall off. Some atoms naturally leak them; this leakage as known as decay. For instance, uranium 238 decays into thorium 234 by shedding alpha particles of neutrons and protons. (The numbers refer to the atomic weight; I'm including them for the one or two hard science types I get here, but the rest of you can ignore them.) Lots of atoms do this, and it's quite a natural process. It's where the majority of our everyday radiation exposure comes from. The danger is when mankind refines the stuff and puts it all in one place, like a bomb or a reactor, and then of course you've got LOTS of particles oozing off at the same time. It's still safe if you shield it properly, but, well, it's typical of humankind. No smarter than refining oil, just different.
All right. I think this is a good place to stop. Tomorrow's topic, "now that I know about radiation, why do I give a shit?"