Comments: Is the AIR Supposed to be Blue?

That's extremely well written for us non-scientists, Aaron, and moving too.

Posted by N E at March 16, 2011 10:31 PM

A flux of gamma rays intense enough to actually make you feel warm would probably kill you. It happened to Louis Slotin, which is presumably what suggested this to you.

Put another way, sunlight is about 1 kilowatt per square meter and that feels warm. 1 kilowatt per square meter would be about 500 watts on a person (assuming 0.5 square meter) and assuming a 100 kg person, they'd pick up a lethal dose in 1 second if sunlight were made of gamma rays. (1 rad is 0.01 J/Kg and a lethal dose is 500 rads, or 5J/kg or 500 Joules for a 100 kg person). So cut the flux down by a factor of 100 and it takes nearly 2 minutes to pick up a lethal dose. I don't know if that would feel warm. The wikipedia article on Slotin doesn't say how long his criticality accident lasted, but I get the impression it was maybe a second or so.

Posted by Donald Johnson at March 16, 2011 11:43 PM

I googled the specific heat of dry air--conveniently it is 1 KJ per kg per Kelvin. So to heat the temperature of the air by 1 degree Celsius you'd have to add 1000 Joules and if that is in the form of gamma rays that amounts to 100,000 rads (or 1000 sieverts using these newfangled units). I'm not sure if 100,000 rads in the air would translate into 100,000 rads absorbed by people and other living things, but I'm guessing that it's going to be in the same ballpark. It probably depends on how many electrons there are per kg of whatever material the gamma rays hit and that's roughly the same for most elements, with hydrogen being about a factor of two higher. But that's also just for one degree of heating.

I think that if Marie's farm had been bathed in gamma rays for hours at a level so intense everything looked blue and the temperature rose so that it felt hot because of the heat added by the gamma rays nothing would have survived on that farm with the possible exception of bacteria or other very tough organisms several feet down in the soil.

That said, I don't know what she saw.

Posted by Donald Johnson at March 17, 2011 12:23 AM

It's the heating portion of Aaron's theory that I'm rejecting. No way anyone survives exposure to gamma ray flux so intense it actually heats the air in a noticeable way. (The people near Slotin noticed it felt hot, but that was probably a matter of seconds or less.) I don't know what sort of dose rates are associated with making air look blue. I sorta suspect it would be lethal also (there was a blue glow in the Slotin episode), and lethal very quickly, but I don't know a quick way to calculate that. You'd have to calculate the number of ionized atoms per second and then figure out how intense a glow that would produce and understand how it would look to the human eye and so on.

Posted by Donald Johnson at March 17, 2011 12:42 AM

I discovered from sending away to my Senator, Sen Charles Percy of Illinois, and requesting the written record of everything that Congress had on this disaster, and then reading that material that the media did not reveal very much to us.

Very few people realize that there was an explosion at Three Mile Island. It is only because that entire complex was built to code that the situation did not go onto a far more deadly China Syndrome.

However it is a common occurrence that the structures dealing with the reactors are not built to code. That whole Republican thing of, You aren't going to tell me how to do something, is a factor regarding skimping on the building code. that and greed.

In the mid to late seventies, I also personally knew a guy who was involved in engineering matters related to putting in the electrical wiring for nuclear plants. (I was friends with his son.) He always talked about how the storage problem was easy to solve - just put the stuff in containers and take it out to Indian reservations. End of problem.

Posted by Carol Dagg at March 17, 2011 04:13 AM

Donald Johnson,

Ohhhh, it's tricky. This is related to the basis of my opinion that all of the health physics models are useless.

You see, I didn't say that the gamma flux heated the air. The path length of energetic gammas in dry air is on the order of meters or tens of meters. There's very little interaction there.

The gamma flux heated the people. The heat reported is from the deposition of gamma ray energy (well, also alpha, beta, and fission fragments, if the hypothesis in this post is correct) into this woman's body. In fact, really just into her skin, which is where we sense temperature.

That could certainly make it feel hot without killing immediately.

Posted by Aaron Datesman at March 17, 2011 07:25 AM

Donald Johnson,

It wasn't the Slotin story which suggested this to me. Actually, I haven't thought about that incident at all while writing this series of posts. What reminded me of it was the irradiated cheap gemstones from the UVA reactor I wrote about in the initial post.

They're blue because gamma ray irradiation strips core shell electrons from the gemstone material. These semi-free electrons are re-captured by other atoms, creating optically active defect sites/excitonic pairs. That's what causes the blue color.

It's a similar thing (not the same) with this post. That was the key which helped me to understand it.

Posted by Aaron Datesman at March 17, 2011 07:40 AM

I think that if you felt heating from gamma rays on your skin then it's also heating your whole body, because the path length of gamma rays in the body is--well, I don't have the figure handy and it presumably depends on the energy, but the mean absorption path or whatever it is called is probably greater than the thickness of a human body. And if you feel hot for hours then it's going to imply a huge radiation dose, way beyond 500 rads. I'm going back to the solar constant turned into gamma ray comparison. Even if you cut the flux by a factor of 100, ten watts per square meter of gamma rays is a lethal dose after a couple of minutes. And I don't know that ten watts per square meter would register as "warm". I just held my hand about a half meter from a 75 watt bulb (about 20 watts/square meter) and I couldn't tell if I felt anything or not. Maybe there'd be some physiological reason that gamma rays would feel warm other than their heating effect.

As for the air, if you've got a big cloud of radioactive material then it is going to heat the air it is in even if the individual photons travel an average of tens of meters before absorption. But we can ignore that part of my argument if you want and restrict the question to what sort of dose rate would cause someone to feel warm.

Alpha particles--well, they wouldn't penetrate your skin, but they also do disproportionate damage compared to gammas for a given amount of energy (which is why I think they multiply by a factor of 20 to calculate the biological equivalent dose rate compared to gammas). If you feel hot from those I don't know that you're going to have any skin. That's the thing about ionizing radiation--energetically speaking it just doesn't take that much to kill you. 500 Joules of sunlight is a warm feeling for a second or so, whereas 500 Joules of gamma rays is a lethal dose for an adult human being. And it would be less for alpha particles, though given their low penetrating power I'm not sure what to say about external bombardment that just heats the skin, other than guessing you don't have any skin after that.

I'd be curious to know if there are reports of intensely blue air in areas of heavy fallout. I'd like to know what level of radioactivity is needed to cause the sort of effect this person saw--I'm guessing it is unreasonably large, but like I admitted before, I don't know how to go about estimating it.

Posted by Donald Johnson at March 17, 2011 08:12 AM

I thought of something else which I think strengthens my argument about the heating effect. Sunlight, of course, is absorbed in the skin. 1 kilowatt per square meter feels quite warm. If you got 1 kilowatt per square meter of absorbed gamma ray energy just in your skin, that's only a small fraction of the total energy absorbed in the rest of your body. Of course, maybe with gamma rays it's the effect of all the heating over the entire body that makes you feel warm, not just what is absorbed in the skin. But then try estimating how much energy it takes to heat 100 kg of water by one tenth of a degree Celsius (to pull a number out of the air). That's 10 kilocalories, or 40,000 Joules, or about 80 times the lethal dose if it is heat from gamma rays.

Posted by Donald Johnson at March 17, 2011 08:26 AM

I assumed if the air was blue, the Cerenkov would explain it as well, because their eyeballs are filled liquid (i.e. similar to your "heating the people" explanation).

It may be a better explanation if the dose required to cause that is survivable.

Posted by James Cape at March 17, 2011 08:40 AM
Therefore, a plausible physical explanation for what happened to Marie Holowka is that she was bathed in a field of gamma rays so intense that it literally TURNED THE AIR BLUE.

The blueness was said to have lasted several days; gamma radiation intense enough to light up the air for that long would have no doubt literally cooked a human. Even a shorter exposure to radiation that intense would have led to acute, unambiguous radiation sickness and death.

Posted by grendelkhan at March 17, 2011 10:50 AM

Donald Johnson (and Aaron)

I don't know a photon's worth of physics, but it looks to me like the question is whether a lot less gamma radiation than killed Slotin (or it would have killed Marie Holowka in nine days or so rather than years) could have still turned the air blue by stripping nitrogen atoms in the air of electrons the way Aaron described. Could that sort of lower-level (but still very bad and eventually probably lethal) gamma radiation have made Marie Holowka feel hot without heating/burning her?

I have no idea how much gamma radiation is needed to turn air blue, but I do know that if you close windows and doors and stuff rags in all the cracks you may well feel a lot warmer than you would with air flow. And that's putting aside how panic and fear can make a person feel warm. So I'd bet that a little bit of warmth from gamma radiation combined with panic and lack of ventilation could maybe make a person feelvery hot.

Posted by N E at March 17, 2011 11:32 AM

NE - yeah, that's true, but if you read the other testimonials in the TMIA archive you'll notice that a lot of them mention how hot it was. Some of the people who made that statement were *outside*.

James - I read the excerpt to imply that there was optical depth to the blueness; that is, she could see her hand, but not the barn (otherwise, why would she mention that she couldn't see the other buildings?) This indicates to me that Cerenkov radiation in the vitreous humor of the eye is not the cause.

Donald - Thanks for these comments, I will ponder them and maybe write a longer post after doing some calculations (or at least more thinking). But one issue we ought to consider is the spectrum of the gamma radiation. That is, were there a lot of 1keV rays, or a few 500keV rays?

Both distributions fit the description of "intense". But I bet that multiple Compton scattering of 500keV gamma rays could turn the air blue without killing a person directly. It is possible that the heat she reported was due to alpha radiation, while the gammas were so strong that they passed right through.

It's complicated to figure out exactly - there are a tremendous number of effects which could have been occuring..... which is one of the things which makes nuclear reactors so dangerous.

BTW, I appreciate everybody who reads and comments on these posts. It makes me feel a little less like I am crazy. (I work at the Department of Energy, where my views are not exactly of the majority....)

Posted by Aaron Datesman at March 17, 2011 01:36 PM

If the flux of blue light was so intense it actually drowns out the background scenery, it suggests that whatever was powering it had an intensity comparable to or greater than the sunlight--that is, more than 1000 watts/square meter. Which leads me back to previous comments. Everyone should have died.

This blue light thing is fascinating, but if there was only one witness I'd be inclined to dismiss it as an hallucination (possibly brought on by illness or even radiation sickness for all I know)--if the rest of her family confirmed it then we've got a real mystery.

The bigger issue is whether there were statistically significant increases in illness and mortality rates after TMI. I did a bit of googling yesterday and found the usual contradictory claims. Sigh.

Posted by Donald Johnson at March 17, 2011 02:32 PM

I must concur with the position that an airborne collection of gamma sources sufficiently dense to actually heat the air to any noticeable extent, or to make it glow visibly, would almost certainly be immediately lethal.

The idea that these may have been localized physiological effects from a more modest radiation exposure (i.e., the air was not actually heated nor actually glowing) seems plausible, but as Aaron notes, the visual impression of an optical depth to the effect would seem to argue against it.

The visual effect could possibly be due to Mie scattering from aerosolized particulates (e.g., ash or smoke, not necessarily radioactive), either scattering sunlight directly or serving as condensation nuclei for water vapor, i.e., forming a fog.

Posted by SunMesa at March 17, 2011 03:27 PM

Several things:

I'm a high school drop-out with a GED so I'm not nearly knowledgeable enough on a lot of these topics.

1.) If I understand correctly, ionizing radiation ionizes. It creates free electrons (negative charge) seeking anything with a positive (or neutral) charge to join up with and become electrically (more) neutral. Ionizing stripped the electron from what it ionized so whatever was struck is now positively charged and looking for an electron to join with to become electrically neutral again. Thus a positive and negative charge - or static. When the ions are in human flesh do they create a current flow? And would this current flow have resistive heating involved? And what sort of voltage would it produce? I don't know, I'm just asking someone who might.

2.) I keep seeing "taste of metal" in conjunction with ionizing radiation, whether here or criticality incidents, or otherwise. To me, brass has always tasted like, well, brass. A "dead" flashlight cell, when wired to, um, "taste the current" tastes like, well, brass. Brass is an alloy of two different metals. Galvanized steel is steel and zinc. Two dissimilar metals in an electrolyte will produce a current. I've always figured the brass taste of brass was low voltage electricity caused by saliva acting as an electrolyte between the zinc and copper. Ionizing radiation strips electrons from the material it collides with - in this case nitrogen - leaving free electrons and their ionized atoms separated to create a voltage potential. Could this account for the "taste of metal" that I keep seeing? Is there any research that you know of on the topic? Or am I the only one who thinks brass and low voltage taste the same? Or am I missing something?

3.) Emitted wavelengths. Gamma striking nitrogen strips electron; electron captured by nitrogen emits photon of blue wavelengths. What emits photons of infrared wavelengths? Of ultraviolet? These would cause heating more than blue.

4.) Would there be anything in the air that when hit with UV (short or long) would then emit blue photons? An iodide or krypton, etc.?

Just grasping at comprehending a fascinating phenomenon.

Posted by Some guy on the innernet at March 17, 2011 04:47 PM

Donald Johnson -

The flux from the sun is 1320 W/m^2. This doesn't mean that the flux from a patch of blue sky away from the sun is 1320 W/m^2. It's obviously much, much less - in fact, a small enough number that it could be quite augmented by ionization recombination.

The sun comparison isn't useful if the gamma rays are so energetic that the pass right through us. That's the piece which makes this hard to understand.

Next week I will post some health figures for mortality from TMI. The information is out there, it only has to be put together. I agree that it's the important aspect. This is a sideshow in some ways, but (in my opinion) important in others, since if the story is true it's very powerful.

I spent most of the day reading scientific articles about gamma ray photoionization, mostly looking for some indication that somebody once had written about the blue glow that Holowka spoke about. Then, of course, I looked up Slotin on wikipedia, which mentions the blue glow. As you had, and which I overlooked.

I have now figured this out, and will post about it. Thanks for challenging me on it and forcing me to think it through.

Posted by Aaron Datesman at March 17, 2011 07:19 PM

I oversimplified on the blue light problem. But we see things because they reflect a fraction of the sunlight that hits them--if the blue light was drowning out nearby objects then that's probably a significant fraction of the 1300 watts/meter squared. But this is probably a more difficult radiative transfer problem than I can do typing in a comment section (and since it's been a long long time since I looked at the subject at all, more difficult than I could probably do.)

As for gamma rays going through us, yeah, but they're not neutrinos either. Here's a link to the thickness of various materials that would stop either 50 percent or 90 percent of the gamma rays of various energies. Notice that the 50 percent thickness for water is in the 10 cm range (though it's a log scale and a little hard to read, I think that at the highest we're looking at maybe 30 cm). So if gamma rays hit us roughly half will be absorbed. (Or anyway, say, 10 to 90 percent, depending on the path and the energy and so forth).


Anyway, I look forward to seeing what you've done.

Posted by Donald Johnson at March 17, 2011 09:00 PM

Also, the heating--unless there is some weird physiological effect that makes gamma radiation seem thermally hot when it is absorbed, it's hard to see how that could explain the heat. A lethal dose of gamma rays is 5 joules/kg and with water or human tissue (which I assume is thermally pretty similar to water) that's going to raise the temperature by about one thousandth of a degree Celsius.

Posted by Donald Johnson at March 17, 2011 09:04 PM

Some guy--I'd try to answer some of your questions, but I'm tired and going offline for now. Maybe Aaron will deal with them to some extent in his next post. I'm curious about the taste question myself, but don't know the answer and haven't googled for it.

Posted by Donald Johnson at March 17, 2011 09:24 PM

Aaron wrote: "I appreciate everybody who reads and comments on these posts. It makes me feel a little less like I am crazy."


Some guy on the innernet wrote: "I'm a high school drop-out with a GED so I'm not nearly knowledgeable enough on a lot of these topics."

You sure could have fooled me.

Donald Johnson:

All your atomic knowledge reminds me of a nuclear historian by the name of Chuck Hansen whom I once knew and helped out a bit. I wish Chuck were around to explain this for me, because like Some Guy on the Innernet, he had a real knack for figuring this stuff out. Without formal training, he became quite the expert: So much so that the government didn't want him to publish some things back in the original war on terror.

Chuck was a great guy.

Posted by N E at March 17, 2011 10:58 PM