Cleaning thermonuclear fire

exactly what would it not take to turn the world into one big fusion reaction, wiping it clean of life and making it a barren rock? Asking for a pal.

Graphic from the 1946 film, “One World Or None,” produced by the nationwide Committee on Atomic Suggestions, advocating for the importance of the international control of atomic power.

One might wonder whether that kind of question provided it self while I became reading the news headlines nowadays, plus one will be totally proper. However the explanation individuals typically ask this real question is in mention of the the story that researchers at Los Alamos thought there is a non-zero chance your Trinity test might ignite the environment throughout the very first wartime test.

The essential concept is a simple one: in the event that you heat up really light atoms (like hydrogen) to very high conditions, they’ll battle around like mad, therefore the chances that they’ll collide into both and undergo nuclear fusion become a great deal greater. If that occurs, they’ll release more energy. Imagine if the very first rush of an atomic bomb started fusion reactions floating around around it, say between your atoms of air or nitrogen, and people fusion responses generated enough power to start out more responses, and so forth, over the whole environment?

It’s difficult to say exactly how seriously it was taken. Its clear that at one point, Arthur Compton concerned about it, and that likewise, a few boffins developed persuasive thinking on effect that this couldn’t take place. James Conant, upon experiencing the searing temperature of the Trinity test, briefly reflected that possibly this rumored thing had, certainly, visited pass:

Then arrived a burst of white light that seemed to fill the sky and appeared to last for seconds. I’d expected a relatively fast and bright flash. The enormity associated with light and its own length quite stunned me personally. My instantaneous reaction was that something choose to go wrong which the thermal nuclear [sic] transformational of the atmosphere, as soon as talked about as possibility and jokingly referred to a few momemts early in the day, had actually taken place.

Which does at the very least tell us that some of those at the test remained joking about this, even around the previous couple of moments. Fermi reportedly took wagers on whether or not the bomb would destroy simply New Mexico or in fact the entire world, nonetheless it had been comprehended as being a laugh.1

The introduction associated with Konopinski, Marvin, and Teller paper of 1946. Filed under: “SCIENCE!“

Into the fall of 1946, Emil Konopinski, Cloyd Marvin, and Edward Teller (whom else?) composed up a paper describing why no detonation in the world ended up being likely to start an uncontrolled fusion response within the environment. It is really not clear to me whether this is often the logic they utilized prior towards the Trinity detonation, but it is most likely of the comparable character to it.2 In a nutshell, there clearly was only 1 fusion reaction in line with the constituents of the air which had any probability anyway (the nitrogen-nitrogen effect), and the scientists were able to show it was not to more likely to take place or spread. No matter if one makes assumptions your response had been much simpler to start than anyone thought it was probably be, it absolutely wasn’t likely to be suffered. The reaction would cool (through a selection of real mechanisms) faster than it might distribute.

That is all a typical section of Manhattan Project lore. But I suspect many who possess read with this prior to never have really see the Konopinski-Marvin-Teller paper to its end, in which they end for a less sure-of-themselves note:

There continues to be the remote possibility that several other less easy mode of burning may keep itself inside atmosphere.

Even if the effect is stopped within sphere of the few hundred meters radius, the resultant earth-shock while the radioactive contamination of the environment might become catastrophic for a world-wide scale.

One may conclude that the arguments of the paper allow it to be unreasonable to expect your N+N effect could propagate. An limitless propagation is even less likely. But the complexity associated with the argument and also the lack of satisfactory experimental foundations makes further work with the subject extremely desirable.

That’s not quite as protected as you might want, considering these boffins were in reality focusing on developing weapons plenty of that time period stronger than the Trinity unit.3

The relevant part of the Manhattan District History (cited below) interestingly links the study to the “Super” hydrogen bomb with the research into perhaps the atmosphere might be incinerated, which makes feeling, though it would be interesting to understand just how closely connected these questions in which.

There is an interesting section in the recently-declassified Manhattan District History‘s that covers the ignition for the environment issue. They repeat fundamentally the Konopinski-Marvin-Teller outcomes, and then conclude:

The impossibility of igniting the atmosphere was therefore guaranteed by science and good sense. The essential factors in these calculations, the Coulomb forces associated with nucleus, are one of the better comprehended phenomena of modern physics. The philosophic likelihood of destroying the planet earth, from the theoretical convertibility of mass into power, continues to be. The thermonuclear response, that is in order to now understood where such a catastrophe could take place, is evidently eliminated. The typical stability of matter in the observable universe contends against it. Further familiarity with the character regarding the great stellar explosions, novae and supernovae, will put light on these questions. Into the almost complete lack of genuine knowledge, it’s generally speaking believed your tremendous energy of those explosions is of gravitational rather than nuclear origin.4

Which again is at the same time reassuring and perhaps not reassuring. The footing which this knowledge was based ended up being… very good? But like good researchers these were happy, about in secret reports, to acknowledge there might actually be methods the earth become damaged through nuclear evaluating that they hadn’t considered. Intellectually honest, but in addition terrifying.

The ever relevant XKCD.

This dilemma arrived up once more prior to the process Crossroads nuclear tests in early 1946, that was to include a minumum of one underwater shot. None other than Nobel Prize-winning physicist Percy Bridgman stressed that detonating an atomic bomb under water might ignite a fusion effect into the water. Bridgman admitted their own ignorance into nuclear physics (his specialization had been high-pressure physics), but warned that:

Even the most readily useful human intellect has not imagination enough to envisage exactly what might take place once we push far into new territory. … To an outsider the tactics regarding the argument which will justify operating perhaps the slightest danger of that colossal catastrophe seems extremely weak.5

Bridgman’s worries weren’t actually your globe could be destroyed. He worried more that if the researchers showed up become cavalier about these specific things, therefore ended up being later on made public that their argument the safety associated with tests was according to flimsy evidence, that it would lead to a strong public backlash: “There might be a response against technology generally speaking which would end up in suppression of all clinical freedom while the destruction of technology itself.” Bridgman’s views were strong enough that they were forwarded to General Groves, but it isn’t clear whether or not they led to any significant modifications (though I wonder when they were the impetus for the write-up of this Konopinski-Marvin-Teller paper; the timing type of calculates, but we don’t understand).

There wasn’t lots of evidence this issue concerned the researchers an excessive amount of moving forward. They had other things on the head, like building thermonuclear weapons, and it quickly became clear that beginning a big fusion reaction by having a fission bomb is hard. Which can be, in its very own means, an answer to the initial concern: if starting a runaway fusion response on purpose is hard, and needs really particular forms of arrangements and factors to have working also on a (relatively) little scale, then beginning one in the entire atmosphere, will probably be impossible.

Operation Fishbowl, Shot Checkmate (1962) — the lowest yield weapon, but something about its perfect symmetry together with path regarding the rocket that put it into the air invokes the notion of a planet turning out to be a celebrity for me. Supply: Los Alamos Nationwide Laboratory.

Great — cross that one from the directory of possibilities. But it wouldn’t really be technology unless they also, in the course of time, re-framed issue: exactly what conditions could be needed whenever we were to turn the complete earth into a thermonuclear bomb? In 1975, a radiation physicist on University of Chicago, H.C. Dudley, published an article inside Bulletin of Atomic Scientists caution of the “ultimate catastrophe” of setting the environment burning. This received a few rebuttals and a lot of scorn, including one in pages associated with Bulletin by Hans Bethe, who’d formerly addressed this concern into the Bulletin in 1946. Interestingly, though, Dudley’s primary desire — that some body re-run these calculations on a modern computer simulation — did seem to generate research along these lines within Lawrence Livermore National Laboratory.6

In 1979, Livermore experts Thomas A. Weaver and Lowell Wood (the latter appropriately a well-known Edward Teller protege) published a paper on “Necessary conditions for the initiation and propagation of nuclear-detonation waves in airplane atmospheres,” which is a jargony way to ask issue into the name with this post. Here’s the abstract:

The basic conditions the initiation of a nuclear-detonation wave in an environment having airplane symmetry (age.g., a thin, layered fluid envelope for a earth or star) are developed. Two classes of these a detonation are identified: those where heat regarding the plasma resembles that the electromagnetic radiation permeating it, and the ones where the temperature associated with plasma is significantly greater. Necessary conditions are developed for the propagation of such detonation waves for an arbitrarily good distance. The contribution of fusion chain reactions to these processes is assessed. Through these factors, it’s shown that neither the environment nor oceans of this Earth may be designed to go through propagating nuclear detonation under any circumstances.7

Now if you simply browse the abstract, you might think it absolutely was merely another version (with fancier calculations) of this Konopinski-Marvin-Teller paper. And so they do rule out conclusively that N+N reactions would ever be energetic sufficient become self-propagating. But it is a lot more! Because unlike Konopinski-Marvin-Teller, it in fact centers around those “necessary conditions”: just what will have to be different, if you did want to have a self-propagating response?

The solution they found: if the Earth’s oceans had twenty times more deuterium than they actually contain, they could be ignited by a 20 million megaton bomb (which will be to say, a bomb utilizing the yield equivalent to 200 teratons of TNT, or perhaps a bomb 2 million times more powerful than the Tsar Bomba’s complete yield). If we assumed that this type of tool had even a fantastically efficient yield-to-weight ratio like 50 kt/kg, that’s still a tool that will weigh around a billion metric tons. To put that into viewpoint, that’s about ten times more mass than all the concrete of Three Gorges Dam.8

So there you have it — it can be done! You simply have to completely change the composition of the oceans and require a nuclear tool numerous instructions of magnitude more powerful than the gigaton bombs dreamed of by Edward Teller, then, perhaps, you’ll display the cleansing thermonuclear fire experience.

Which will be to express, this won’t be exactly how the planet dies. But don’t worry, there are plenty other plausible alternatives for human self-extinction around. They simply probably won’t be as quick.


I will be undergoing completing my book manuscript, that will be the actual work of the summer, therefore most other writing, including blog posting, is going for a back chair for a few months while We concentrate on that. The irreverent name of this post is obtained from a recurring theme into the Twitter feed of anthropology grad student Martin “Lick the Bomb” Pfeiffer, whose work you should have a look at when you yourself haven’t currently.

(The Impossibility of) Lighting Atmospheric Fire,” does a very good task of reviewing a few of the wartime conversations and clinical problems.

  • Emil Konopinski, Cloyd Marvin, and Edward Teller, “Ignition for the Atmosphere with Nuclear Bombs,” (14 August 1946), LA-602, Los Alamos National Laboratory. Konopinski and Teller additionally apparently composed an unpublished report about them in 1943. I have only seen mention of the it, as report LA-001 (suspiciously like the LA-1 that is the Los Alamos Primer), but have not seen it.
  • Teller, in October 1945, wrote the following to Enrico Fermi about the chance for a “Super” detonating the environment, as part of that which was basically a “Frequently expected Questions” in regards to the H-bomb: “Careful considerations and calculations have shown that there’s not the remotest likelihood of such an occasion [ignition associated with the atmosphere]. The concentration of energy encountered in super bomb just isn’t higher than that the atomic bomb. In my experience the risks were greater once the first atomic bomb had been tested, because our conclusions had been based in those days on longer extrapolations from understood facts. The chance associated with the super bomb doesn’t lie in physical nature however in human being behavior.” What I find most fascinating concerning this is his comment about Trinity, though Teller’s rhetorical point is an apparent one (overstate the Trinity uncertainty after the fact to be able to emphasize their certainty currently). Edward Teller to Enrico Fermi (31 October 1945), Harrison-Bundy data associated with the Development for the Atomic Bomb, 1942-1946, microfilm publication M1108 (Washington, D.C.: nationwide Archives and reports Administration, 1980), Roll 6, Target 5, Folder 76, “Interim Committee — Scientific Panel.”
  • Manhattan District History, Book 8, amount 2 (“Los Alamos – Technical”), paragraph 1.50.
  • Percy W. Bridgman to Hans Bethe, forwarded by Norris Bradbury to Leslie Groves via TWX (13 March 1946), copy in Nuclear Testing Archive, Las vegas, nevada, NV, document NV0128609.
  • H.C. Dudley, “The Ultimate Catastrophe,” Bulletin associated with Atomic researchers (November 1975), 21; Hans Bethe, “Can Air or liquid Be Exploded?,” Bulletin of the Atomic experts 1, no. 7 (15 March 1946), 2; Hans Bethe, “Ultimate Disaster?,” Bulletin of the Atomic researchers 32, no. 6 (1976), 36-37; Frank von Hippel, “Taxes Credulity (Letter towards the Editor),” Bulletin of Atomic boffins (January 1946), 2.
  • Thomas A. Weaver and Lowell Wood, “Necessary conditions for the initiation and propagation of nuclear-detonation waves in plane atmospheres,” Physical Review A 20, no. 1 (1 July 1979), 316-328. DOI: https://doi.org/10.1103/PhysRevA.20.316.
  • Specifically, they conclude it might take a 2 x 107 Mt power release, which they call “fantastic,” to ignite an ocean of 1:300 (instead of the actual 1:6,000) concentration of deuterium. Being an apart, but the collision event that created the Chicxulub Crater (and killed the dinosaurs, etc.) is believed to own released around 5 x 1023 J, which means about 120 million megatons of TNT. So’s not a totally unreasonable energy release for the earth to encounter during the period of its presence — simply not from nuclear weapons.
  • Operation Crossroads at 70

    This summer is the 70th anniversary of Operation Crossroads, the first postwar nuclear test series. Crossroads is so strange and unusual. 1946 in general ought to get more credit as an interesting year, as I’ve written about before. It was a year in flux, where a great number of possible futures seemed possible, before the apparently iron-clad dynamics of the Cold War fell into place. Crossroads happens right in the middle of the year, and arguably made a pretty big contribution to the direction that we ended up going. Such is the subject of my latest article for the New Yorker‘s Elements blog, “America at the Atomic Crossroads.” Today is the anniversary of the Baker shot, which Glenn Seaborg dubbed “the world’s first nuclear disaster.”

    America at the Atomic Crossroads

    There are a lot of things that make Crossroads interesting to me. The bomb was still in the hands of the Manhattan Project. The Atomic Energy Act of 1946 had not yet been signed into law (Truman would sign it in August, and it would go into effect in January 1947), so the Atomic Energy Commission did not yet exist.

    There were these amazing interservice rivalry aspects: the whole backdrop is a Navy vs. Army tension. The Manhattan Project, and the Army Air Forces, had gotten all the glory for the bomb. The Navy didn’t want to be left out, or seen as irrelevant. Hence them hosting a big test, and glorying in the fact that a Nagasaki-sized atomic bomb doesn’t completely destroy a full naval squadron. (Which was no surprise to anybody on the scientific or military side of things.)

    The US had only about 10 atomic bombs at the time. So they expended about 20% of their entire nuclear arsenal on these tests, for relatively little military knowledge gained. The Los Alamos scientists were pretty lukewarm on the whole operation — it just didn’t seem like it was getting them much. One wonders, if the bomb had not still be under military control, whether it would have happened.

    Photograph of the early mushroom cloud by LIFE photographer Frank Scherschel, with a darkened filter to compensate for the brightness of the flash. Source.

    Photograph of the early mushroom cloud of Crossroads Able by LIFE photographer Frank Scherschel, with a darkened filter to compensate for the brightness of the flash. Source.

    The first shot, Able, was something of a flub. The fact that it missed its target meant that for public relations purposes it was seen as very ineffective, but it also means that their scientific observations were largely pretty useless. In fact, it missed its target and blew up over one of the main instrumentation ships.

    If you read most sources about Crossroads they will say that the source of the Able miss was undetermined, but if you dig down a little deeper you find some pretty plausible solutions (and the reason why the official verdict was “undetermined”). Paul Tibbets, the captain of the Enola Gay and overall head of the atomic delivery group, was pretty clear that it was human error. He said that even before the shot they realized that the crew of the B-29 which dropped it, Dave’s Dream, had gotten bad information about the weather conditions, but that they ignored attempts at correction. Tibbets would re-run (with a dummy bomb) the drop with the correct information (and got very close to the target), and also re-ran it with the wrong information (which missed by nearly the same amount as the Able shot). But the USAAF really didn’t want to throw their bombardier and plane crew under the bus. So they hinted it might be a problem with the ballistics of the weapon (which were indeed a bit tricky), which infuriated the Manhattan Project officials. Anyway, everyone seems to have been satisfied by just saying they couldn’t figure out where the error was. But Tibbets’ account seems most plausible to me.1

    Crossroads was not secret operation, though there was much classified about it. There were full-spread articles about its purpose in national news publications both before and after its tests. There was probably no test series so publicly conducted by any nuclear power — announced well in advance, covered by the press in real-time, and then heavily publicized afterwards. The fact that the Soviets were invited to a US nuclear test operation (something that would not happen again until the late-1980s) opens up whole other dimensions.

    Mikhail Meshcheryakov ("Mike"?) in 1946. At right he is on the USS Panamint, at the Crossroads test. Source: Mikhail Grigorivich Meshcheryakov, on the 100th-anniversary of his birth (Dubna, 2010).

    Mikhail Meshcheryakov  in 1946. At right he is on the USS Panamint, at the Crossroads test. Source: Mikhail Grigorivich Meshcheryakov, on the 100th-anniversary of his birth (Dubna, 2010).

    The Soviets had three observers at the test: Professor Semyon P. Aleksandrov, a geologist who had worked on the prospecting of uranium; Mikhail G. Meshcheryakov, an experimental physicist; and Captain Abram M. Khokhlov, who attended as a member of the international press corps (he wrote for the Soviet periodical Red Fleet). I found a really amusing little anecdote about the Soviet observers from one of the men who worked the Manhattan Project security detail on Crossroads: Aleksandrov was someone they knew already (he was a “dear old geologist”), but Meshcheryakov was someone “whose name was known, but no one had met personally leading some of us to support he was really an NKVD agent watching Aleksandrov.”

    I found nothing in the Russian source materials (mentioned below) that would indicate that Meshcheryakov was NKVD, though he was definitely the one who wrote up the big report on Crossroads that was given to Beria, who summarized it for Stalin. Meshcheryakov’s report is not among the declassified documents released by the Russians, so who knows if it has any political commentary on Aleksandrov in it. Meshcheryakov ended up having a rather long and distinguished physics career in the USSR, though there is almost no English-language discussion of him on the Internet. Aleksandrov, the “dear old geologist,” was actually a major Soviet big-wig in charge of mining operations, which at that time meant he was high in the Gulag system, which was run by the NKVD. For what it’s worth.2

    Radiation from the Crossroads Baker shot — the radiation went up with the cloud, and then collapsed right back down again with it, resulting in a very limited extent of radiation (the entire chart represents only 4.5 miles on each axis), but very high intensities. Chart source: DNA 1251-2-EX. Collapsed cloud picture source: Library of Congress.

    Radiation from the Crossroads Baker shot — the radiation went up with the cloud, and then collapsed right back down again with it, resulting in a very limited extent of radiation (the entire chart represents only 4.5 miles on each axis), but very high intensities. Chart source: DNA 1251-2-EX. Collapsed cloud picture source: Library of Congress.

    It was also something of the real birth of “atomic kitsch.” There are some examples from before Crossroads, but there is just a real flourishing afterwards. It seems to have taken a year or so after Hiroshima and Nagasaki for enough time to have passed for Americans to start to regard nuclear weapons entirely frivolously. With Crossroads in particular, a deep connection between sex and death (Freud’s favorites) circled around the bomb. This is where we start to see the sorts of activities that would later result in the “Miss Atomic Bomb” contests, the release of the really kitchy songs, and, of course, the Bikini swimsuit, named after the “atomic bomb island,” as LIFE put it.

    The key fulcrum of my article is a meditation on the “crossroads” metaphor, and I should probably note that it was, to some degree, intentional. Vice Admiral William Blandy was reported by the New York Times to have told Congress, that the name was chosen for its “possible significance,” which the Times writer interpreted to mean “that seapower, airpower, and perhaps humanity itself — were at the crossroads.”3

    An unusual color (but not colorized!) photograph of the Crossroads Baker detonation, from LIFE magazine. Source.

    An unusual color (but not colorized!) photograph of the Crossroads Baker detonation, from LIFE magazine. Source.

    What’s interesting to me is that Blandy clearly saw some aspects of the “crossroads,” but there was much he couldn’t have seen — the atomic culture, the arms race, the contamination, the nuclear fears. He knew that “crossroads” was a good name for what they were doing, but it was an even better name than he could have known, for both better and worst.


    As before, I wanted to take a moment to give some credit/citation information that wasn’t workable into the New Yorker blog post (where space, and thus academic nicety, is constrained).

    The best overall source on Crossroads, which I found invaluable, is Jonathan Weisgall’s Operation Crossroads: The Atomic Tests at Bikini Atoll (Naval Institute Press, 1994). Weisgall has been a legal counsel on behalf of the Marshallese, and his book is just a wealth of information. I was pleased to find a few things that he didn’t have in his book, because it’s a really tough challenge given how much work he put into it. If you find Crossroads interesting, you have to read Weisgall.

    Rita Hayworth on the Crossroads Able bomb, "Gilda." Photo by Los Alamos National Laboratory, via Peter Kuran and Bill Geerhart.

    Rita Hayworth on the Crossroads Able bomb, “Gilda.” Photo courtesy Los Alamos National Laboratory, via Peter Kuran and Bill Geerhart.

    Bill Geerhart, who writes the excellent blog CONELRAD Adjacent (and is the one behind the Atomic Platters series of Cold War songs), has done some really wonderful work on the cultural aspects of Crossroads over the years. His posts on the mushroom cloud cake, and his sleuthing regarding the Rita Hayworth connection, are amazing and worth reading in their entirety. Peter Kuran, the visual effects wizard who made the documentary Trinity and Beyond, among other films and works, was very helpful in providing recently-declassified imagery of the Crossroads bombs, including photos (which I first saw on Geerhart’s blog) of the Rita Hayworth image on the side of the bomb themselves. (I will be writing more about Kuran and his work in the near future…)

    Holly Barker’s Bravo for the Marshallese (Thomson/Wadsworth, 2004), is immensely useful as an anthropologist’s view of the Marshallese people and their experiences after the test. My invocation of the Marshallese language for birth defects comes directly from Barker’s book, pages 81 and 106-107. It is a powerful, disturbing section of the book.

    Selection from Life magazine's coverage of Crossroads — two visions of the animal testing. Source.

    Selection from Life magazine’s coverage of Crossroads — two visions of the animal testing. Source.

    Most of the information I got about the Soviet view of Crossroads comes from the multi-volume Atomniy Proekt SSSR document series released by the Russian Federation. I had the full set of these before it was cool, but now Rosatom has put them all online. Scholars have been picking over these for awhile (I have written on them once before), I haven’t seen anybody use the particular documents relating to Crossroads before, but you in Tom (Volume) 2, Kniga (Book) 6, the documents I found most useful were 44 (pp. 130-132), 48 (135-136), 50 (137), 76 (184-188), and 106 (246-248). They show the picking of the delegation of observers, brief biographies of the observers, a summary of Meshcheryakov’s report (his full 110-page report on Crossroads is not included), and some later aspects of Meshcheryakov’s involvement with the planning of the first Soviet nuclear test in 1949 (in which his Bikini experience was offered up as his bonafides).

    The other really unusual little source I used for my article is the letter from Percy Bridgman. The letter was sent from Bridgman to Hans Bethe, who relayed it to Norris Bradbury at Los Alamos, who sent it to General Groves. You can read it here. I have been sitting on it for a long time — I almost wrote a blog post about it in 2012, but decided not to for whatever reason. When I worked at the American Institute of Physics I had an opportunity to poke around Bridgman’s life and writings a bit, and he’s really an interesting character. He was the one at Harvard who served as J. Robert Oppenheimer’s physics advisor, and his own work on high-pressure physics not only won him the Nobel Prize of 1946 (which is a nice coincidence for the Crossroads article), but also was used (and is still classified, as far as I can tell) on the Manhattan Project (they seem to have sent him plutonium samples, so you can imagine the kind of work he was doing and why it might still be classified — almost everything on plutonium under high pressures is classified in the United States).

    Percy W. Bridgman (L) talking with Harvard colleague (and future Trinity test director) Kenneth Bainbridge, 1934. Source: Emilio Segrè Visual Archives, American Institute of Physics

    Percy W. Bridgman (L) talking with Harvard colleague (and future Trinity test director) Kenneth Bainbridge on a Massachusetts beach, 1934. Source: Emilio Segrè Visual Archives, American Institute of Physics.

    Bridgman gave a number of talks associated with his Nobel Prize that really tried to get at the heart of what the effects of World War II would be for physics as a discipline. He was very much afraid that Big Science (which hadn’t yet been given that name) would really destroy work like his own, which he saw as small-scale, individual, and not focused on particular applications. He was also very interested in topics related to the philosophy of science, something that a lot of modern-day practicing physicists openly disdain. His Wikipedia page gives a nice, brief overview of his life, and even touches on the poignant circumstances of his death.4.

    Notes
    1. This is discussed at length in Jonathan Weisgall’s Operation Crossroads, pp. 201-204.
    2. The account of the security officer is Charles I. Campbell, A Questing Life: The Search for Meaning (New York: iUniverse, 2006). This appears to be a self-published memoir, the sort of thing one would never run across without Google Books. On Aleksandrov’s Gulag connections (which seem plausible given his uranium connections), see this page on his Hero of Socialist Labor award. One of the few English-language articles on Meshcheryakov is available here.
    3. Sidney Shallet, “Test Atomic Bombs to Blast 100 Ships at Marshall Atoll,” New York Times (25 January 1946), 1. Blandy’s full quote on the name from the testimony: “The schedule of target dates for this operation, which will be known by the code word ‘CROSSROADS’—and I would like to explain that we have chosen that merely for brevity in dispatches and other communications, and we chose it with an eye to its possible significance—now calls for the first test to be accomplished early in May, over target ships at an altitude of several hundred feed.” A lot of the sources about Crossroads include Shallet’s bit about “perhaps humanity itself” as a quote of Blandy’s, but it’s not in the transcript that I can see. Hearing before the Special Committee on Atomic Energy, United States Senate, Pursuant to S. Res. 179, Part 4, 79th Congress, 2nd Session (24 January 1946), on 457.
    4. The citation for the Bridgman letter is: Percy W. Bridgman to Hans Bethe, forwarded by Norris Bradbury to Leslie Groves via TWX (13 March 1946), copy in the Nuclear Testing Archive, Las Vegas, NV, document NV0128609.