Posts Tagged ‘Musings’


The plutonium box

Friday, March 28th, 2014

I’ve found myself in a work crunch (somehow I’ve obligated myself to give three lectures in the next week and a half, on top of my current teaching schedule!), but I’m working on some interesting things in the near term. I have a review of Eric Schlosser’s Command and Control coming out in Physics Today pretty soon, and I’ll post some more thoughts on his book once that is available. And I have something exciting coming up for the 60th anniversary of Oppenheimer’s security hearing.

In the meantime, I wanted to share the results of one little investigation. I’ve posted a few times now (Posing with the plutoniumLittle boxes of doom, The Third Core’s Revenge) on the magnesium boxes that were used to transport the plutonium cores used for the Trinity test and the Fat Man bomb:

The magnesium cases for the world's first three plutonium cores. Left: Herb Lehr at Trinity base camp with the Gadget core. Center: Luis Alvarez at Tinian with the Fat Man core. Right: The third core's case at Los Alamos, 1946.

The magnesium cases for the world’s first three plutonium cores. Left: Herb Lehr at Trinity base camp with the Gadget core. Center: Luis Alvarez at Tinian with the Fat Man core. Right: The third core’s case at Los Alamos, 1946.

Just to recap, they were a design invented by Philip Morrison (the Powers of Ten guy, among other things), made out of magnesium with rubber bumpers made of test tube stoppers. They could hold the plutonium core pieces (two in the case of the Trinity Gadget, three in the case of Fat Man), as well as neutron initiators. Magnesium was used because it was light, dissipated heat, and did not reflect neutrons (and so wouldn’t create criticality issues). All of this information is taken from John Coster-Mullen’s Atom Bombs, an essential book if you care about these kinds of details.

But all of the photographs of the box I had seen, like those above, were in black and white. Not a big deal, right? But I find the relative lack of color photography from the 1940s one of those things that makes it hard to relate to the past. When all of Oppenheimer’s contemporaries talked about his icy blue eyes, it makes you want to see them as they saw them, doesn’t it? Maybe it’s just me.

The only place where I almost saw a color photo of the box is in a photo that the late Harold Agnew had taken of himself on Tinian. It’s one of a large series of posing-with-plutonium photos that were taken on the island of Tinian sometime before the Nagasaki raid. Only this one is in color! Except… well, I’ll let the photo speak for itself:

Harold Agnew with plutonium core redacted

Yeah. Not super helpful. This was scanned from Rachel Fermi and Esther Samra’s wonderful Picturing the Bomb book. They asked Agnew what had happened, and he told them that:

I was in Chicago after the war in 1946. The FBI came and said they believed I had some secret pictures. They went through my pictures and found nothing. Then like a fool I said, “Maybe this one is secret.” They wanted to know what that thing was. I told them and they said that it must be secret and wanted the picture. I wanted the picture so they agreed if I scratched out the “thing” I could keep the slide.

Thwarted by nuclear secrecy, once again! You can try to look extra close at the scratches and maybe just make out the color of the “thing” but it’s a tough thing to manage.

Ah, but there is a resolution to this question. Scott Carson, a retired engineer who posts interesting nuclear things onto his Twitter account, recently posted another  photo of the box — in color and unredacted! His source was a Los Alamos newsletter from a few years back. It is of Luis Alvarez, another member of the Tinian team, in the same exact pose and location as the redacted Agnew photograph… but this time, un-redacted! And the color of the box was…

Luis Alvarez with the Fat Man core, Tinian, 1945.

…yellowNot what I was expecting.

Why yellow? My guess: it might be the same yellow paint used on the Fat Man bomb. Fat Man was painted “a mustard yellow rust-preventing zinc-chromate primer” (to quote from Coster-Mullen’s book) that made them easier to spot while doing drop tests of the casings.

The box for the Trinity core doesn’t look painted yellow to me — it looks more like raw magnesium. Maybe they decided that the tropical atmosphere of Tinian, with its high humidity, required painting the box to keep it from oxidizing. Maybe they just thought a little color would spruce up the place a little bit. I don’t know.

Does it matter? In some sense this is pure trivia. If the box was blue, green, or dull metallic, history wouldn’t be changed much at all. But I find these little excursions a nice place to meditate on the fact that the past is a hard thing to know intimately. We can’t see events exactly as they were seen by those who lived them. Literally and figuratively. The difficulty of finding out even what color something was is one trivial indication of this. And the secrecy doesn’t help with that very much.


Art, Destruction, Entropy

Friday, December 13th, 2013

Are nuclear explosions art? Anyone who has taken even a glance into modern and contemporary art knows that the official mantra might as well be “anything goes,” but I found myself wondering this while visiting the exhibition “Damage Control: Art and Destruction since 1950” that is currently at the Hirshhorn Museum. The first thing one sees upon entering is a juxtaposition of two very different sorts of “work.” On the right is a fairly long loop of EG&G footage of nuclear test explosions, broadcast in high definition over an entirety of a wall. On the left is a piano that has been destroyed with an axe. This, I thought, is at least a provocative way to start things off.

Edgerton, Germeshausen, and Grier (EG&G) was a contractor for the federal government during the Cold War, responsible for documenting nuclear test explosions. Quite a lot of the famous Cold War nuclear detonation footage was taken by EG&G. They are perhaps most famous for their “Rapatronic” photographs, the ultimate expression of MIT engineer Harold “Doc” Edgerton’s work of slowing down time through photography, but this was only a part of their overall contribution. The film they have at the Hirshhorn is something of an EG&G “greatest hits” reel from the 1950s, and its affect on the others in the audience was palpable. Adults and children alike were drawn to the blasts, displayed one after another without commentary or explanation.1 Their reactions didn’t strike me as one of disgust or horror, but of amazement and awe. Most of the footage was from the Nevada Test Site, so the bombs were generally just blowing up desert scrub, and occasionally houses constructed for effects testing.

The destroyed piano, by contrast, got reactions of shock and disgust. It was the remains of a piece of performance art conducted by Raphael Montañez Ortiz, one of several he’s done, apparently. My wife, a piano player and a nuclear historian, also found it disturbing. “If you know what goes into making a piano…,” she started to say. “But then again, if you know what goes into making a city…,” she caught herself. I overheard other people say similar things.

The difference in reactions isn’t too surprising — it’s a common theme that it is easy to appreciate the destruction of something at a human scale, difficult to appreciate it at the scale of nuclear bomb. A lot of what I’ve spent time doing, with the NUKEMAP and my writing, is to try to understand, and to impart, the scale of a nuclear explosion. A lot of this has involved looking at the attempts of others, as well, from official Cold War visualizations made for secret committees to popular films, as they have tried to communicate this to their target audiences. The hardest thing is that our brains appear only to be wired for empathy at the individual level, and don’t readily apply it to large groups or large areas. The best work in these areas conveys both the broad scope of destruction, but then ties it into the personal. They individualize the experience of mass ruination.

And the EG&G footage isn’t trying to do that. It was data meant for very specific technical purposes. It was developed in order to further the US nuclear program, and defense against Soviet nuclear weapons. Which is why I somewhat question its inclusion, or, at least, its decontextualization. It is art only in the sense that it has aesthetics and it has been put into an art gallery. One can read into it whatever one wants, of course, but it wasn’t created to have deep meaning and depth in that sense. (Whether one cares about authorial intention, of course, is its own can of modern art worms.) Just as a small example of what I mean, Andy Warhol famously made a print of mushroom clouds for his own “disaster” series (a few of which, but not this print, were featured in the exhibit):

"Atomic Bomb," Andy Warhol, 1965.

“Atomic Bomb,” Andy Warhol, 1965.

Now Warhol is a complicated character, but since he was explicitly an artist I think it is always fair game to talk about his possible intentions, the aesthetics of the piece, the deeper meanings, and so on. Warhol’s art has generally been interpreted to be about commercialization and commodification. The mushroom cloud in repetition becomes a statement about our culture and its fascination with mass destruction, perhaps. Coming in the mid-1960s, after the close-call terrors of the early years of the decade, perhaps it was maybe too-little too-late, but still, it has an ominous aesthetic appeal, perhaps now more than then.

Because I don’t think this image was widely circulated at the time, I doubt that Warhol knew that Berlyn Brixner, the Trinity test photographer, had made very similar sorts of images of the world’s first nuclear fireball at “Trinity”:

TR-NN-11, Berlyn Brixner, 1945.

“TR-NN-11,” Berlyn Brixner, 1945.

Brixner appreciated the aesthetics and craft of his work, to be sure. But the above photograph is explicitly a piece of technical data. It is designed to show the Trinity fireball’s evolution over the 15-26 millisecond range. Warhol’s instrument of choice was the silkscreen printer; Brixner’s was the 10,000 fps “Fastax” camera. There’s a superficial similarity in their atomic repetition. You could make a statement by putting them next to each other — as I am doing here! — but properly understood, I think, they are quite different sorts of works.

Don’t get me wrong. Re-appropriating “non-art” into “art” has been a common move over much of the 20th century at the very least. But the problem for me is not that people shouldn’t appreciate the aesthetics of the “non-art.” It’s that focusing on the aesthetics makes it easy to lose sight of the context. (As well as the craft — Brixner’s work was exponentially more difficult to produce than Warhol’s!) The EG&G footage in the exhibit doesn’t explain much of how, or why, it was made. It seems to be asking the viewer to appreciate it solely on its aesthetic grounds. Which I think is the real problem. Many of the tests they show resulted in significant downwind fallout for the populations near the Nevada Test Site. Many of them involved the development of new, ever-more elaborate ways of mass destruction. Many of them were the product of years of top scientific manpower, untold riches, and a deep political context. To appreciate them as simply big, bright booms robs them of something — no matter how aesthetically beautiful those big, bright booms actually are. 

Gustav Metzger's "auto-destructive" art.

Gustav Metzger’s “auto-destructive” art.

What makes it more ironic is that the exhibit actually does give considerable context to some of the works that are explicitly “art.” You have to explain the context of Gustav Metzger’s “auto-destructive” art — it involves him filming himself painting on canvases with a strong acid, so the artwork destroys itself in the process. Without the context there, what is left is just a boring, not-very-comprehensible movie of a man destroying a blank canvas. But anyway.

In terms of the audience at the exhibit, which was fairly well-attended when I was there with my wife, the most interesting part was the handling of children. The Smithsonian museums are of course explicitly places that people take their children while visiting the city, so it’s no surprise that you probably find more of them at the Hirshhorn than you would at MOMA or other similar institutions. But children add a level of anxiety to an exhibit about destruction. They were wowed by the wall-o’-bombs but not, it seemed, by the piano. Parents seemed to let them wander free through most of it, but there were several films where I saw kids get yanked out by their parents once the parents realized the content was going to be disturbing. In one of these films, the “disturbing” content was of a variety that might have been hard for the children to directly understand — the famous film of the Hindenburg going up in flame, for example, where the violence was real but seen from enough of a distance to keep you from seeing actual injuries or bodies. The one I saw the kids getting really removed from (by their parents, not the museum) was footage of the 2011 Vancouver riots. I wasn’t impressed too much with the footage itself (its content was interesting in a voyeuristic way, but there seemed to be nothing special about the filming or editing), but the immediacy of its violence was much more palpable than the violence-at-a-distance that one saw in most of the other such works. It’s cliche to trot out that old quote attributed (probably wrongly) to Stalin that one death is a tragedy, a million is a statistic, but there’s something deeply true to it about how we perceive violence and pain.

Damage Control exhibit site

There are a lot of works in the exhibit. As one would expect, some hew to the theme very closely, some are a bit more tenuous. Overall, though, it was pretty interesting, and if you’re in town, you ought to check it out. The original comment my wife made about pianos and cities stuck with me as I looked at all of the various meditations on “destruction.” In it, I kept coming back to the second law of thermodynamics. On the face of it, it is a very clinical, statistical law: “the entropy of an isolated system never decreases.” It is actually quite profound, something that the 19th-century physicists who developed it knew. Entropy can be broadly understood as “disorder.” The second law of thermodynamics says, in essence, that without additional energy being put into it, everything eventually falls apart. It takes work to keep things “organized,” whether they are apartments, bodies, or cities.2 Ludwig Boltzmann, who helped formulate the law, stated gnomically in 1886 that:

The general struggle for existence of animate beings is not a struggle for raw materials – these, for organisms, are air, water and soil, all abundantly available – nor for energy, which exists in plenty in any body in the form of heat Q, but of a struggle for [negative] entropy, which becomes available through the transition of energy from the hot sun to the cold earth.

In other words, life itself is a struggle against entropy. Our bodies are constantly taking disordered parts of the world (heat energy, for example, and the remains of other living things) and using them to fuel the work of keeping us from falling apart.

But the other way to think about this law is that generally it is easier to take things apart than it is to keep them together. It is easier to convert a piano into a low-energy state (through an axe, or perhaps a fire) than it is to make a piano in the first place. It is easier to destroy a city than it is to make a city. The three-year effort of the half-a-million people on the Manhattan Project was substantial, to be sure, but still only a fraction of the work it took to make the cities of Hiroshima and Nagasaki, and all that they contained, biological and material, in the first place.

Of course, the speed at which entropy increases is often controllable. The universe will eventually wear out — but not for a long time. Human civilization will necessarily go extinct — but it doesn’t have to happen anytime soon. What hits home with the “Damage Control” exhibit is how we as a species have to work so hard to keep everything together, while simultaneously working so hard to find ways to make everything fall apart. And in this, perhaps, it is a success, even if I left with many niggling questions about the presentation of some of the works in particular.

  1. Various guys in the audience would occasionally try to give explanation to their loved ones, and they were generally incorrect, alas. “That must be at Alamogordo… That’s got to be an H-bomb…” no, no, no. Of course, I was there with my wife, and I was talking up my own little storm (though less loudly than the wrong guys), but at least I know my stuff for the most part… []
  2. The key, confusing part about the second law is the bit about the “isolated system.” It doesn’t say that entropy always increases. It says that in an isolated system — that is, a system with no energy being input into it — entropy always increases. For our planet, the Sun is the source of that input, and you can trace, through a long series of events, its own negative entropy to the Big Bang itself. []

The Hiroshima-Equivalent: A Modest Proposal

Friday, June 7th, 2013

Given that the media community seems to love comparing all manners of energy release to Hiroshima, no matter how inappropriate, I humbly propose a new scientific unit: the Hiroshima-equivalent, abbreviated as H-e.

Hiroshima damage map

The Hiroshima-equivalent has been pegged at exactly 15 kilotons of TNT,1 which is itself defined as being equivalent to 62.76 terajoules, or 15 teracalories.

One of the many benefits of using the H-e is that one can apply it to any type of energy release, not simply things physically similar to atomic bombs. Indeed, one should not, in any way, worry about whether the phenomena one is applying it to is anything like the actual bombings of Hiroshima. The H-e is in no way logically connected to blast phenomena, heat phenomena, ionizing radiation, radioactive fallout, or deaths upwards of a hundred thousand people. It can be applied to situations involving energy releases that occur over vastly larger areas of time and space, and in situations where only handful of people are hurt or injured. What is important about using the H-e is that you use it in a way that grabs the attention of your readers who are, as you know, bored, inattentive, and continually distracted by a multitude of empty facts, bad television, and meaningless digital social interactions.

In order to facilitate easy adoption of the Hiroshima-equivalent scale, I’ve created a simple calculator below. Here you can plug in a number of different types of energy expressions and find out their Hiroshima-equivalents. Precise energy measurements, such as Joules or Kilowatt-hours or Kilocalories, have that boring, “professional” feel to them, and as such are much less interesting than their Hiroshima-equivalent values.

(The above calculator is embedded in a frame; if you cannot see it, click here to open it as a separate window.)

Because sometimes energy releases are too small to be considered in unit multiples of Hiroshima-equivalents, I have, naturally, also created metric prefixes of milli-Hiroshima-equivalents (.001 H-e), micro-Hiroshima-equivalents (.000001 H-e), and nano-Hiroshima equivalents (.000000001 H-e). I have not opted to use positive prefixes (e.g. kilo-Hiroshima-equivalents) because it is much more exciting to instead say “thousands times the size of the Hiroshima bomb,” obviously.

So using this new system and calculator, some fascinating facts emerge:

  • The bomb detonated over Hiroshima was exactly 1 Hiroshima-equivalent. As one would expect, but imagine the headlines if this had been around in August 1945: “FIRST ATOMIC BOMB IS DROPPED ON JAPAN; MISSILE IS EQUAL TO ENERGY OF HIROSHIMA BOMB; TRUMAN WARNS OF A ‘RAIN OF RUIN.’
  • The Sun deposits 61.34 billion Hiroshimas worth of energy onto the Earth every year — that’s 168 million Hiroshimas a day, 7 million Hiroshimas an hour, 117 thousand Hiroshimas a minute!
  • The USA uses about 24 thousand Hiroshima-equivalents worth of electricity per year!
  • The Haitian Earthquake of 2010 was equivalent to around 32 Hiroshimas! (Alas, not a new conclusion.) Note that this system doesn’t work for determining the yields of underground nuclear tests, because actual nuclear weapons have more complicated energy release mechanisms when underground. (Pesky details!)
  • Each year, McDonald’s sells around 26 Hiroshima-equivalents worth of Big Macs in the United States alone, 42 Hiroshima-equivalents worldwide (1 H-e = 21.4 million Big Macs)!
  • My electric bill for last month was for 4.42 micro-Hiroshima-equivalents! (Which is 126.2 nano-Hiroshima-equivalents less than this month last year!)

There are, alas, some cases in which the Hiroshima-equivalent may lose its reader stopping power. For such cases, you may use the alternative unit, the Tsar Bomba-equivalent (TB-e), which is conveniently defined as 33,300 Hiroshima-equivalents. It should be used sparingly and tastefully, along the lines of “The 2004 Indian Ocean earthquake and tsunami [released less energy] than that of Tsar Bomba, the largest nuclear weapon ever detonated.”

In case it isn’t clear how to use this, here are some simple instructions: Whenever there is a natural disaster, explosion, or, really, anything relating to energy that just doesn’t have enough pathos, tragedy, or excitement for your average reader, call up a scientist at a university somewhere, ask them to calculate how much energy was released in the event in question. He or she will probably give you some nonsense about “Joules” or “Kilowatt hours” or “Calories.” Take those meaningless numbers, paste them into the right places on the calculator, and you’ll instantly know how many Hiroshima-equivalents you are talking about! You simply can’t go wrong.

  1. There are lots of estimates for the size of the Hiroshima bomb. Online one can find numbers range from 12-20 kilotons of TNT. A study by Los Alamos found that the best estimate of the yield for Hiroshima was 15±3 kilotons. For the purposes of a standard unit, of course, one must simply pick a number, and 15 seems appropriate in this circumstance. I note that it is tempting to define it as the lower limit, 12 kilotons, because that would mean even more Hiroshima-equivalents for any given situation, but we must have some standards. []

Narratives of Manhattan Project secrecy

Friday, March 29th, 2013

Secrecy suffused every aspect of the Manhattan Project; it was always in the background, as a context. But it’s also a topic in and of itself — people love to talk about the secrecy of the work, and they’ve loved to talk about it since the Project was made public. In the 1940s there was something of a small industry of articles, books, and clichés regarding how secret the atomic bomb was kept. Of course, the irony is… it wasn’t really kept all that well, if you consider “keeping the secret” to involve “not letting the Soviet Union know pretty much everything about the atomic bomb.” (Which was, according to General Groves, one of the goals.)

It’s easy to get sucked into the mystique of secrecy. One way I’ve found that is useful to help people think critically about secrecy (including myself) is to focus on the narratives of secrecy. That is, instead of talking about secrecy itself, look instead at how people talk about secrecy, how they frame it, how it plays a role in stories they tell about the Manhattan Project.

One of many early articles in the genre of Manhattan Project secrecy: "How We Kept the Atomic Bomb Secret," from the Saturday Evening Post, November 1945.

One of many early articles in the genre of Manhattan Project secrecy: “How We Kept the Atomic Bomb Secret,” from the Saturday Evening Post, November 1945.

My first example of this is the most obvious one, because it is the official one. We might call this one the narrative of the “best-kept secret,” because this is how the Army originally advertised it. Basically, the “best-kept secret” narrative is about how the Manhattan Project was sooo super-secret, that nobody found out about it, despite its ridiculous size and expense. The Army emphasized this very early on, and, in fact, Groves got into some trouble because there were so many stories about how great their secrecy was, revealing too much about the “sources and methods” of counterintelligence work.

The truth is, even without the knowledge of the spying (which they didn’t have in 1945), this narrative is somewhat false even on its own terms. There were leaks about the Manhattan Project (and atomic bombs and energy in general) printed in major press outlets in the United States and abroad. It was considered an “open secret” among Washington politicos and journalists that the Army was working on a new super-weapon that involved atomic energy just prior to its use. Now, it certainly could have been worse, but it’s not clear whether the Army (or the Office of Censorship) had much control over that.

Panel from FEYNMAN by Jim Ottaviani and Leland Myrick.

Panel from FEYNMAN by Jim Ottaviani and Leland Myrick.

We might contrast that with the sort of narrative of secrecy that comes up with regards to many participants’ tales of being at places like Los Alamos. Richard Feynman’s narrative of secrecy is one of absurd secrecy — of ridiculous adherence to stupid rules. In Feynman’s narratives, secrecy is a form of idiotic bureaucracy, imposed by rigid, lesser minds. It’s the sort of thing that a trickster spirit like Feynman can’t resist teasing, whether he’s cracking safes, teasing guards about holes in the fence, or finding elaborate ways to irritate the local censor in his correspondence with his wife. All participants’ narratives are not necessarily absurd, but they are almost always about the totalitarian nature of secrecy. I don’t mean “fascist/communist” here — I mean the original sense of the word, which is to say, the Manhattan Project secrecy regime was one that infused every aspect of human life for those who lived under it. It was not simply a workplace procedure, because there was no real division between work and life at the Manhattan Project sites. (Even recreational sports were considered an essential part of the Oak Ridge secrecy regime, for example.)

So we might isolate two separate narratives here — “secrecy is ridiculous” and “secrecy is totalitarian” — with an understanding that no single narrative is necessarily exclusive of being combined with others.1

"Beyond loyalty, the harsh requirements of security": Time magazine's stark coverage of the 1954 security hearing of J. Robert Oppenheimer.

“Beyond loyalty, the harsh requirements of security”: Time magazine’s stark coverage of the 1954 security hearing of J. Robert Oppenheimer.

But the Feynman approach looks perhaps unreasonably jolly when we contrast it to the narrative of J. Robert Oppenheimer and his students, for whom secrecy became something more sinister: an excuse to blacklist, a means of punishment. Oppenheimer did fine during the Manhattan Project, but the legacy of secrecy caught up with him in his 1954 security hearing, which effectively ended his government career. For his students and friends, the outcomes were often as bad if not worse. His brother, Frank, for example, found himself essentially blacklisted from all research, even from the opportunity to leave the country and start over. (It had a happy ending, of course, because without being blacklisted, he might never have founded the Exploratorium, but let’s just ignore that for a moment.)

For a lot of the scientists involved in the Manhattan Project, secrecy ended up putting their careers on the line, sometimes even their lives on the line. In response to (fairly ungrounded) suspicions about Oppenheimer’s student Rossi Lomanitz, for example, Groves actually removed his draft deferment and had him sent into the dangerous Pacific Theatre. This narrative of secrecy is what we might classically call the “tragic” narrative of secrecy — it involves a fall from grace. It emphasizes the rather sinister undertones and consequences of secrecy regimes, especially during the period of McCarthyism.

The original "best-kept secret" story, released on August 9, 1945 (the day of the Nagasaki bombing).

The original “best-kept secret” story, released on August 9, 1945 (the day of the Nagasaki bombing).

So what other narratives are there? Here is a short list, in no particular order, that I compiled for a talk I gave at a workshop some weeks ago. I don’t claim it to be exhaustive, or definitive. Arguably some of these are somewhat redundant, as well. But I found compiling it a useful way for me to think myself around these narratives, and how many there were:

  • Secrecy is essential”: early accounts, “best-kept secret” stories
  • Secrecy is totalitarian”: secret site participants’ accounts
  • Secrecy is absurd”: e.g. Feynman’s safes and fences
    • Common hybrid: “Secrecy is absurdly totalitarian
  • Secrecy is counterproductive”: arguments by Leo Szilard et al., that secrecy slowed them down (related to the “absurd” narrative)
  • Secrecy is ineffective”: the post-Fuchs understanding — there were lots of spies
  • Secrecy is undemocratic”: secrecy reduces democratic participation in important decisions, like the decision to use the bomb; fairly important to revisionist accounts
  • Secrecy is tragic”: ruinous effects of McCarthyism and spy fears on the lives of many scientists
  • “Secrecy is corrupt: late/post-Cold War, environmental and health concerns

It’s notable that almost all of these are negative narratives. I don’t think that’s just bias on my part — positive stories about secrecy fit into only a handful of genres, whereas there are so many different ways that secrecy is talked about as negative. Something to dwell on.

What does talking about these sorts of things get us? Being aware that there are multiple “stock” narratives helps us be more conscious about the narratives we talk about and tap into. You can’t really get out of talking through narratives if you have an interest in being readable, but you can be conscious about your deployment of them. For me, making sense of secrecy in an intellectual, analytical fashion requires being able to see when people are invoking one narrative or another. And it keeps us from falling into traps. The “absurd” narrative is fun, for example, but characterizing the Manhattan Project experience of secrecy makes too much light of the real consequences of it.

As an historian, what I’m really trying to do here is develop a new narrative of secrecy — that of the meta-narrative, One Narrative to Rule Them All, the narrative that tells the story of how the other narratives came about (a history of narratives, if you will). Part of talking about secrecy historically is looking at how narratives are created, how they are made plausible, how they circulate, and where they come from. Because these things don’t just appear out of “nowhere”: for each of these narratives, there is deep history, and often a specific, singular origin instance. (For some, it is pretty clear: Klaus Fuchs really makes the “ineffective” narrative spring to live; Leo Szilard and the Scientists’ Movement push very hard for the “counterproductive” narrative in late 1945; the “best-kept secret” approach was a deliberate public relations push by the government.)

As a citizen more broadly, though, being conscious about narratives is important for parsing out present day issues as well. How may of these narratives have been invoked by all sides in the discussions of WikiLeaks, for example? How do these narratives shape public perceptions of issues revolving around secrecy, and public trust? Realizing that there are distinct narratives of secrecy is only the first step.

  1. Both of these might classically be considered “comic” narratives of secrecy, under a strict narratological definition. But I’m not really a huge fan of strict narratological definitions in this context — they are too broad. []

On Meteors and Megatons

Tuesday, February 19th, 2013

So by now, everybody has read about the meteor which broke up over the Chelyabinsk Oblast late last week. The reportage on it was pretty interesting in the beginning — a lot of between-the-lines skepticism was being put out there by American news outlets. I was a little wary myself, too, as a lot of the initial reports from Russia were pretty sketchy, buffeted primarily by Russian dashboard cameras, which, in our Photoshop and AfterEffects age, are probably not at the top of our list of “reliable sources.” For people who care about Cold War science and technology, of course, there’s the additional fact that ChelyabinskOblast is a major site for secret Russian military-industrial developments. It’d be like reports of suspicious explosions around the Nevada Test Site, or Los Alamos, or Pantex. Chelyabinsk Oblast is the home of Chelyabinsk-70, the Soviet Livermore, and just north of it is the city of Sverdlovsk (now Yekaterinburg), the site of a 1979 anthrax leak that the Soviets tried to cover up by claiming it was something more “natural” in origins. Add in the legacy of the Soviet response to Chernobyl, the relative rarity of this sort of meteor strike — once a century is the frequency that’s been cited — and the extreme rarity of something like this happening over inhabited land — most of the planet is devoid of human occupation — and some skepticism in the absence of solid evidence was, I think, not unwarranted. Eyebrows raised, including mine, but apparently it all checks out.

Some of the Russian nuclear weapons facilities near the meteor path. Via Hans M. Kristensen, FAS: "The odds of a meteor hitting one of these nuclear weapons production or storage site are probably infinitely small, but on a cosmic scale it got pretty close."

Some of the Russian nuclear weapons facilities near the meteor path. Via Hans M. Kristensen, FAS: “The odds of a meteor hitting one of these nuclear weapons production or storage site are probably infinitely small, but on a cosmic scale it got pretty close.”

How powerful was the explosion? NASA currently is saying it is the equivalent of a 500 kiloton blast, which is a lot. 500 kilotons is (as you can see) half a megaton, is about the upper-limit of a pure-fission nuclear weapon, and is, as journalists love to breathlessly relate, some 20-30 times the power of the bombs that hit Hiroshima and Nagasaki. That the only result was a lot of injuries caused by windows blowing inward — something that occurs with a shock wave of one pound per square inch or above — is attributed to the fact that the meteor exploded many miles above the ground, away from the city.

Personally, I cast a dubious eyeball towards the comparisons of natural phenomena with nuclear weapon energy releases. It’s an incredibly common trope, though. Wikipedia’s coverage of the 2004 Indian Ocean earthquake is actually quite reflective of how this gets talked about, even if it is somewhat dorkier in its citation of units than the average journalistic account:

The energy released on the Earth’s surface only (ME, which is the seismic potential for damage) by the 2004 Indian Ocean earthquake and tsunami was estimated at 1.1×1017 joules, or 26 megatons of TNT. This energy is equivalent to over 1500 times that of the Hiroshima atomic bomb, but less than that of Tsar Bomba, the largest nuclear weapon ever detonated. However, the total work done MW (and thus energy) by this quake was 4.0×1022 joules (4.0×1029 ergs), the vast majority underground. This is over 360,000 times more than its ME, equivalent to 9,600 gigatons of TNT equivalent (550 million times that of Hiroshima) or about 370 years of energy use in the United States at 2005 levels of 1.08×1020 J.

Lots of numbers thrown around, lots of energy involved, yes, but what does it mean? I have two major objections to this form of analysis, where nuclear weapons are used as some kind of barometer for general energy release.  The first is about the character of energy release is important — because it affects how these things are felt at the human scale. The second is about whether these sorts of comparisons are actually clarifying to the general public.

On the character of nuclear and non-nuclear blasts

The key thing about nuclear weapons is that they discharge most of their energy as heat and blast. Most of the energy release occurs over a very small amount of space and time. You can essentially regard the physics of a nuke as being a the creation of a tiny point in space that suddenly is heated to tens of millions of degrees, and this results in all of the effects that we are pretty well familiar with. The results are extremely localized: even the massive Tsar Bomba had a fireball only five miles in diameter, which is huge by human standards but minute by geological or geographical standards. The vast majority of the energy is discharged within a few milliseconds, as well. It’s a bang that matters on a human level because a huge amount of energy is released very quickly in an area of space that corresponds fairly well to the sizes of human habitation centers. The fact that a huge amount of that explosive energy (around 50%)  is translated specifically as a blast wave — the thing which destroys most of the houses and people and all that — is perhaps the most salient thing about nuclear explosions from a human standpoint.


This is what a 500 kiloton nuclear blast looks like. This is not quite the same thing as what you saw on those dashboard cameras, is it?

One can see the point in distinguishing about the amount of energy over time and space by considering the Sun. The amount of energy from the Sun that reaches the Earth’s surface every moment is tremendous — equivalent to billions of tons of TNT – but it is spread out over a huge area, so instead of totally obliterating us when we go outside, it pleasantly warms us and maybe, at its worst, gives us a painful, peeling burn after several hours of intense exposure. So that is a lot of energy released over a short unit of time, but it is diffused over a very large area. The converse situation can also be considered: a given city absorbs an immense about of energy from the Sun over the course of a year, but because it is spread out in time, it isn’t anything like a nuclear explosive’s yield.

What about meteors? Yes, there’s a lot of kinetic energy in those rocks falling from the sky. But they don’t translate most of that energy into shock and heat. Even the famed 1908 Tunguska event reached temperatures “only” in the tens of thousands of degrees, as opposed to the tens of millions. You can regard the kinetic energy of such a thing as 20 megatons of yield, but the actual blast effects were more than five times less than that because the energy didn’t transfer very efficiently. (Still quite a blast, though!) The Chelyabinsk meteor was much smaller than that and it exploded in the atmosphere — a reaction more like a chemical explosive than a nuclear one. So in some sense, comparing a meteor explosion to a nuke is better than comparing an earthquake or a tsunami to a nuke, but it’s still not very exact.1

On the public understanding of nuclear explosions

My other issue, though, is about public understanding. The Chelyabinsk meteor exploded with an energy release of 500 kilotons. Is being told that going to mean anything to the average person, except to say, if it had hit the city, it would have been equivalent to a nuclear explosion? Does saying it is 20-30 times more powerful than Hiroshima mean anything to the average person, except the conjure up potentially incorrect misconceptions of what those effects would be for their cities? The truth is, as we’ve seen again and again, the average person has almost no intuitive point of reference for making sense of nuclear explosions. Heck, I barely have any point of reference and I’m constantly searching for them! The average person cannot distinguish between the results of a megaton-range explosion and a kiloton-range one unless you translate it into terms that are meaningful to them. That was the whole point of the NUKEMAP: to take these numbers and try to come up with geographical representations that make intuitive sense.

And so here’s the problem: since the physics aren’t the same, any intuitive generalization made from a nuclear analogy will be necessarily highly flawed. The effects of the Chelyabinsk meteor were not really equivalent to the 1952 Ivy King nuclear detonation, which was a nuclear explosion of 500 kilotons in yield. Even the Tunguska event was not really equivalent to a five megaton nuclear explosion in its phenomenological effects, even though it was a pretty big boom.

Still from a Sandia supercomputer simulation from 2007 of the 1908 Tunguska event, showing the blast wave formation as the meteor detonates above the ground. Intense! But not a nuke. Source.

Still from a Sandia supercomputer simulation from 2007 of the 1908 Tunguska event, showing the blast wave formation as the meteor detonates above the ground. Intense! But not a nuke. Source.

“Hey,” you object, “we’re just trying to communicate to people it was a big explosion!” Yeah, I know, but it’s misleading. If you want to communicate the size of things, don’t talk about the energy release in terms of nukes — the effects aren’t the same. If you want to convey the effects… talk about the effects. A better way to talk about the Chelyabinsk event is to not talk about the energy output but instead to talk about the radius and nature of effects — exactly how many square miles of the city had their windows blown out? Even just saying that thousands were injured by broken glass does a lot more work to convey what this was — and how scary it was — than anything else. If you want to say, “if it had directly hit the city before blowing up” — a big counter-factual but whatever — “so-many square miles would have been destroyed,” that too would make a lot more sense.

Using nukes as a genericized way to talk about energy output is highly misleading both from the point of view of the expert, but even more so from the point of view of the layman. I really don’t see the advantage to it either way. I fear in talking about asteroids as nuke equivalents people may be trying to emphasize their threat — which is totally legitimate — but at the same time may end up inadvertently down-playing nukes. After all, if a 500 kiloton airburst only knocked in a few windows, what’s all the fuss? Yes, we can explain why they are different — but we wouldn’t have to do that if we just described the effects better in the first place, rather than taking a lazy recourse in how-many-joules-equals-how-many-megatons equations. Rather than using nuclear terminology, and then down-scaling to explain how the effects are actually not quite the same… just tell us the actual effects and forget the nukes! If one must do things in response to nukes, do it the other way around: find out the actual effects of the meteor (or whatever), then tell us what yield nuke gives you those effects. It’s less sensational, sure, but it’ll help people understand both meteors and nukes better.

  1. For helping me think through the physical comparisons, and providing some interesting references, I was aided by e-mail conversations with my AIP colleagues Charles Day, Paul Guinnessy, and Ben Stein, as well as my old Harvard colleague Alex Boxer. Any interpretive errors are of course my own! []