A Daily History of Holes, Dots, Lines, Science, History, Math, the Unintentional Absurd & Nothing |1.6 million words, 7500 images, 4 million hits| Press & appearances in The Times, Le Figaro, MENSA, The Economist, The Guardian, Discovery News, Slate, Le Monde, Sci American Blogs, Le Point, and many other places... 4,200+ total posts
I had never seen this video/film before last night--it is pretty solid, and interesting, and I'm a little surprised because for a general-public sort of production it makes some good-sized presumptions of its audience in relation to any physics background. Most of all though there are appearances of Albert Einstein (at 52:15 and 1:01:14), Otto Frisch (1:03:00) and J.D. Cockcroft (1:17:50).
Source: U.S. National Archives http://research.archives.gov/description/88106
Here's a very useful tool for the early days of nuclear fission and atomic energy--the bibliography from William Stephen's Nuclear Fission and Atomic Energy (published by the Science Press in 1948). The OCR is a little unsteady but the info is there even if it isn't as clear as it might be.
The full text for the work is found at the Internet Archive, here: https://archive.org/details/nuclearfissionan030064mnb
Also see the excellent Louis Turner bibliography for nuclear fission, 1934-1940 (133 items) in an earlier post on this blog, here: http://longstreet.typepad.com/thesciencebookstore/2013/08/turners-bibliographic-review-of-nuclear-fission-1934-1940.html
Partial Bibliography on Nuclear Fission and Transuranic Elements
Frederick Rockett's Crises Civil Defense and Deterrence makes a curious display of itself on it title page, what with no punctuation and all--same for the title page, though that changes a little to Crisis Civil Defense and Deterrence. With a comma here and there, the title changes meanings a bit. In any event with my little screed over the document was published by the Hudson Institute in 1967 and is actually about how the Soviet Union, China and some other countries could reduce their vulnerability to nuclear attack by undertaking (emergency) civil defense precautions like large-scale evacuations and fallout protection. The author adopts a curious term here--"hostages"--to apply to the civilian population in relation to the nuclear policy of deterrence. And what that means is that with increased numbers of civilians surviving there would be a greater recover capability after a nuclear strike; in deterrence, enemy populations are part of the scheme, being seen as "hostages" to a nuclear strike and therefore a deterrent for that country to initiate an attack. With an increase in the number of survivors to an attack via the civil defense advancements there are fewer "hostages" and therefore the concept of deterrence is weakened, perhaps to the point where countries could begin to think of first-strike capacity with a more-protected population.
[The original document is available for sale at the blog's bookstore, here.]
And so down the rabbit hole we go, discussing mine shaft gaps. This is five year after Dr. Strangelove, but this was very real stuff--and I imagine that if I were in a position to have to think about nuclear strikes and deterrence and etc., I probably would have been thinking in these terms, too.
This report on Exercise Spadefork was issued at the very beginning of the Cuban Missile Crisis on October 1,1962. Undertaken by the National Resource Evaluation Center (NREC) and other agencies it was supposed to give a good indication of what happens after a very large nuclear attack on the United States, “Measuring the Capability of Survival”, evaluating what remains of the country and its sovereignty.
The theoretical attack began at 3pm, Friday 21 September 1962. 221 nuclear missiles were exploded in/over the U.S. In the first hour, with a total of 355 in the first 48 hours. [I'm not sure that the Soviet Union had 221 intercontinental ballistic missiles at this time, nowhere near that, unless of course they were able to get their 700-missile medium-range ballistic missiles closer to the U.S.]
A total of 1, 779 megatons were exploded almost equally between ground and air bursts.
20 were 1 megaton; 15 were 10 megaton, and 320 were 5 megaton.
The Hiroshima weapon was about 20 kilotons, so in the roughest sense each one of the 5 megaton weapons carried about 250 Hiroshima weapons; the total 1,779 megaton delivery would (grossly) be equal to about 178,000 Hiroshima weapons.
Most of the attack was delivered against military sites, “population and industrial centers appeared to be secondary targets, with only about 50 major centers receiving signifcant amount of blast damage”. Somehow “no major sections of the country were isolated due to fallout contamination”.
How we make out:
Military & “Sovereignty”: not so bad. Air Force and Navy take major hits (something approaching 50% casualties) but the Army does better, not being targeted so heavily, with 20% losses.
This is a good, typical portrait of Enrico Fermi--the thing that makes it "unusual" I think is that it comes with the official caption and also is dated just a few days after the bombing of Hiroshima and Nagasaki.
[Source: private. 6 1/2 x 4 1/2 inches, sepia-toned, head-and-shoulders portrait of Fermi.]
The photograph is definitely original and at the very least an issue of either a news photo service agency or the U.S. Government. Given how quickly the image was released with its association to the atomic bomb (just four days after Hiroshima) I'm guessing that this is a federal source. My limited experience with governmental press releases concerning the atomic bomb leads me to believe that this was issued on 10 August--the government no doubt had prepared documents like this for pre-release (as we have seen with the initial Trinity tests and documents associated with that), but I feel confident that this photo and description are in fact in the first wave of "publicity" following the use of the bombs at Hiroshima and Nagasaki.
We saw it, and prepared for it, the Impossible Thing, the oncoming of megakilll, or what Henry Adams called The Distinguished Thing, acknowledged and prepared and built ourselves a reserve of anti-fear for it.
Once the Soviets demonstrated their capacity to field and then deliver an atomic weapon in August 1949, the great race to Armageddon was underway, a zero-sum game of nuclear dimensions, where an canonical victor is mostly that in name once the million-megaton war was fought and over.
The best that could be done so far as the general American population was concerned was to stockpile foods, recognize the sounds and sights of an attack, pay attention to the EBS, and possibly prepare for the worst by digging a fallout shelter, or hide under your wooden desk at school, or wear an atom bomb suit, or build an atom bomb house. Of course if you lived in the 100+ metro areas that were deemed targetable you could also plan your escape route; however,
since hundreds of thousands(and more) other drivers would be thinking the same thing, getting out of town might not be a possibility. (This was true even if you paid to one of the government-issue nuclear attack evac maps and stayed to the even/east odd/west as dictated by your car's tags, there would still be an impossible mess.)
[Image source: Yesterday's Tomorrows: Past Visions of the American Future, by Joseph J. Corn, a slender and pretty book and very easy to underestimate--it is a wonderful work of real depth and reach, remarkable given its brevity.]
The Atom Bomb House, by Robert C. Scull and Jacques Martini, was designed and published in 1946, and for all intents and purposes supposed that the house and furnishing and all inside it would be safe from an atomic attack. The blast walls around the house's perimeter are a curious touch, and actually look pretty nice--I don't know how much they would deflect the effects of an atomic bomb, though. Still, it was a way around thinking about the impossible.
Making the next logical leap, I guess, the architect Paul Laszlo presented Atomville in 1954, which was a collection of dwellings and structures that were bomb-survival as part of a design-survivable community.
And of course there was some thinking about making each person their own Atomville, with atomic bomb suits (which I wrote about earlier on this blog, here):
[Source: U.S. Patent and Trademark Office, via Google Patents]
So for 15 or 20 years of getting ready for the Soviets to attack Americans were probably desensitized to what that attack actually meant--after hundreds or thousands of warnings and exposure to the possibility of war and nuclear holocaust, many people grew immune to what it all actually meant, swirling away in the mists of Mutually Assured Destruction like a bad song that you know by heart because you've heard it on the radio fifty times.
Then there were those like Ed Teller who thought to spend the equivalent of many multiples of trillions of dollars in the hopes of spreading the country out so that there was an equal distribution of people and factories and such, making the U.S. impossible to attack because there were no centers of population and industry, meaning that the USSR would have to attack everything, everywhere. This would have involved building 20 million new homes and all of the infrastructure that goes along with that, as well as moving all business and relocating all of the means of production in the United States. That was a towering idea that towered low, but it did represent another line of thinking on survivability that moved from the Atom Bomb House to Atomville to the seeming opposite of those, to AtomExUrbia. (See here for the fuller story.)
[Image source: LIFE magazine in (15 June) 1947]
So preparing for the worst, preparing for the thing that you really couldn't prepare for, became an object of desire.
It was as though people could not see the forest for the trees--which is quite ionic, because one piece of nuclear weapon test films that is no doubt very familiar to most anyone over 40 depicts a "forest" being blown apart by a blast. The "forest" was actually a stand of trees constructed in the Nevada desert to see what would happen to flammable trees in a nuclear conflagration. ("...The U.S. Forest Service brought 145 ponderosa pines from a nearby canyon and cemented them into holes lined up in tidy rows in an area called Frenchman Flat, 6,500 feet from ground zero. Then the Department of Defense air-dropped a 27-kiloton bomb that exploded 2,423 feet above the model forest..." on May 8, 1953.1) Not surprisingly, they were mostly destroyed, even using a tactical nuclear weapon. I guess that the issue was not if they would be destroyed but how destroyed they would be. Still, looking at a forest and looking at a nuclear weapons test would leave little doubt that the forest would be pretty-well destroyed--it's just the distance that the destruction would reach would be open to question.
1. Check here for the atomic bomb test on the artificial forest in the Nevada desert (an article by Ann Finkbeiner in Slate).
Well: this is "inside" the book in which nuclear fission is announced--the backstrip/spine was pulled away on one edge from my um "lovely" copy of Naturwissenschaften, volume 27, 1939, to reveal the chocolatey-nugget equivalent of the guts of a book. This is the famous volume which contains (at least) six seminal contributions in the history of nuclear physics including the big one by Otto Hahn and Fritz Strassman (on January 6) in which they announce the discovery of uranium fission1. The spine cover is still hinged on one side, making it a convenient flap to see the covering for the glue etc. holding the sewn signatures and the spine together.
The anatomy of the book reveals a pretty and interesting art-ish composition, with a surprise: there are major elements of Albert Ein(stein's) name display, clear as an azure sky of deepest summer (a line by Peter O'Toole from The Ruling Class).
This is highly appropriate. Einstein naturally knew of all o these developments and felt deeply threatened by them because of the next step, which would be atomic-bomb-building. So on August 2, 1939, he and Leo Szilard wrote a letter to Franklin Roosevelt urging American development towards this end, because surely the Germans would be up to it as well. Although written in August the letter (the first of three) would not be delivered by Szilard to the President until October. I think that it can be safely said that this meeting was the first step in the development of the Manhattan Project. Roosevelt's immediate reaction in this meeting was to insist that the U.S. do The Mega Big Something to ensure that "the Nazis don't blow us up".
In any event, I found it at first artistic and then weirdly interesting that Einstein's name almost appears in the hidden part of this important volume.
1. This would be cleared up further as nuclear fission by Lise Meitner in the February 11 1939 issue of the journal Nature.
The papers contained in this volume of Naturwissenschaften:
HAHN, Otto and Fritz Strassmann. Six papers announcing the discovery of nuclear fission, including:
"Über den Nachweis und das Verhalten der bei der Bestrahlung des Urans mittels Neutronen entstehenden Erdalkalimetalle" (On the detection and characteristics of the alkaline earth metals formed by irradiation of uranium with neutrons)
____. Nachweis der Enstehung aktiver Bariumisotope aus Uran und Thorium durch Neutronenbestrahlung' Nachweis weiterer aktiver Bruchstucke bei der Uranspaltung.
____. Uebervdie Bruchstucke beim Zerplatzen des Urans
____. Zur frage nach dervEzistenz der "Trans-Urane".
____. Weite Spaltproduckte aus der Bestrahlung des Urans mit Nuetronen.
____. F. Strassmann und S. Fluegge. ueber einige Bruchstuckebeim Zerplatzendes Thoriums.
All in Die Naturwissenschaften volume 27. The volume of 862pp.
'Russia reveals Cobalt Bomb; total World Destruction Ahead", ending of Philip K. Dick's "Exhibit Piece", 1952
I never really thought that much about what Dr. Strangelove was fiddling with to calculate the "half life of cobalt thorium-G" in Stanley Kubrick's mega-dystopian steam-nuke 1962 film, Dr. Strangelove. (We've looked at this film a number of times on this blog--just search the title in the Google search box to see the others.) So I went to some clips online and found a still showing him putting away his circular slide, which turns out to be the 1962 version of the "Nuclear Bomb Effects Computer" that was published and issued along with Sam Glasstone's The Effects of Nuclear Weapons (published by the Department of the Army as No 39-3, one edition n a continuing series.
My calculator is actually from the 1964 edition of the work--there seems to be no difference from computer to computer, but there are differences in the text of the book, one of which relates directly to Dr. Strangelove. There is a very brief, barely-two-page section called "Radiological Warfare" in the chapter dealing with radioactive contamination from nuclear weapons. there is nothing overtly technical in it, though the writers seem not to like the idea, given the inherent difficulties in producing and storing such advanced gamma radiation weapons, saying too the the use of such beasts would be either "impossible of very hazardous". The author also makes the point that the high fission energy yields of the new bombs, which make them "in effect, weapons of radiological warfare".1
Here's the reverse of the computer, rendered in black and white:
So, that's it. Dr. Strangelove though wasn't the first to discus a cobalt-laced dirty dirty dirty bomb, with the idea managing to surface several times in the '50's (as with the PKD example, above, and Fritz Lieber's Moon is Green, 1952, where there are cobalt bombs galore, then things happen, and then everything goes badly). The ideas of total destruction+total destruction=total destruction seems to have originated with Leo Szillard in a radio broadcast from the University of Chicago in February 1950 with the introduction of the cobalt-based bomb, which produces a far more intense radiation than U-238. Szillard presented his case as a what-we-will-soon-be-capable-of argument, putting not the destruction of entire cities into question, but the entire planet.
This is about the final minute of the movie, when Dr. Strangelove finds himself rising and walking by a secret Fuhrer-based miracle, his little computer still in his hand. And then seconds later the really bad stuff happens.
[Original document available from the blog's bookstore.]
The spoiler answer to this: make sure to account for the nukes dropped on you when figuring out what you've got left to work with.
ITEM: The Bomb Damage Problem, AFAPA-4-4, published in 1954 by the Directorate of Management Analysis (DCS/Comptroller at the Headquarters of the U.S. Air Force). 11x8 inches. GVC binding. 22pp. Very good condition. RARE. No copies located in WorldCat. $175.
This seems a tautologically tongue-twisting, not-quite-right title for this post, and indeed it might be. But that's the way the pamphlet I'm reporting on read, a sometimes resilient-to- inspection rubberie beastie whose basis for being written was to report on an great oversight that doesn't really want to be recognized, even if it is the title of the work.
The Bomb Damage Problem, AFAPA-4-4, published in 1954 by the Directorate of Management Analysis (DCS/Comptroller at the Headquarters of the U.S. Air Force) is a pamphlet of discovery–or rather, the discovery of the lack of discovery.
The work is an introduction to some aspects of nuclear exchange post-attack predictive capacity–particularly with the ability of American industry “to support a war plan”.
The anonymous pamphlet gets straight away to the discovery part–that previous predictions of post-attack capacity were “probably completely unrealistic” because “[they] did not take account of the likely bomb damage to the U.S. production facilities”.
I would think that even at this relatively early point of planning for possible Soviet nuclear attack that war game scenarios would have taken bomb damage to industry a”and accompanying manpower losses” into account of how the war machine would react after the bombs began to explode. Though it seems not. I’ve looked to see how I could be misreading this thing because it seems like too monumental an oversight to make. But I can’t find where I’m making my interpretative mistake.
Ultimately the authors focuses on saving the corpus of the overall works, saying that this oversight does not damage the “important thinking” that had gone on it spite of this error.
The word “error: is not used in the text of course. This is how it is described: “In connection with this critical new obstacle to intelligent military planning, it is essential that speculation be minimized.” The error is actually redefined as a “critical new obstacle” the effect of which heightens “speculation”. Which is all true.
I suppose what is really going on his the formation of some bedrock stuff formulating information gathering for creating a computer program for deeper analytical study of the effects of nuke warfare on post-attack industry. 1954 is about right for the time for this to happen, and the DMA–as the home for the creation of linear programming among countless other things–would’ve been the place for this work to happen.
But I keep coming back to what seem to be enormous understatements–even giving plenty of allowance for the time–that keep cropping up in the pamphlet. Perhaps it is just stating the obvious for te first time that makes all of these seem so potentially underwhelming, like this nugget: “numerous measures of the importance of each target may eventually be needed....” (Page 7).
There’s plenty of more detail though that occurs in the pamphlet, as in figuring out damage to structures by the yield of the explosion and distance from the target and the composition of the target’s structure, and so on.
And then we get back to the obvious: “the principal effect of a fire storm following an attack would be to enlarge the area of destruction and to alter the shape of the various damage zones, changing them from concentric rings to irregular patterns. “. As I said, maybe it is just a case of a “Call me Ishmael”, or stating that lines and points in space exist for the purpose of geometry. Still, it rubs me the wrong way, all over.
And just to make this point perfectly clear: the "bomb damage" problem is to take into account bomb damage to U.S. war-making, bomb-producing capacity, in a sort of BIBO (bomb in, bomb out) version of a SISO (shit in, shit out).
Describing computer programs "Picnic" for biological/chem weapons damage, and "Dusty" , for radioactive casualties
This was an interesting read, though it took a little while to actually understand what it was I was reading. Mathematics and Computation Laboratory, National Resource Evaluation Center, Analytical Program Compendium NREC Technical Manual No. 119 (Revised) was pritned on December 1964, housed in the covers of the Executive Office of the President NREC/Office of Emergency Planning. The prose is mostly congestive, but after a bit you can pick up the rhythm and it becomes more user-friendly.
Preface signed by Joseph D. Coker, Chief, National resource Evaluation Center, who writes: "The Analytical Program Compendium gives a brief description of the National Resource Evaluation Center's current general purpose analytical programs and replaces earlier editions of the NREC Glossary of Damage Assessment Programs. It is intended as a guide for users and potential users of these programs to indicate the various programs that are presently available and those that are being produced. Separate Technical Reports or Technical Manuals are available for the standard operating programs and for a number of those which are in preparation. Reference to these manuals and reports can be obtained in the Bibliography of Publications (Technical Manual No. 121) published by the NREC. The Compendium contains descriptions of the computer programs of a substantive nature."
[Can't live without this Cold War document? See out blog bookstore to purchase the original.]
The list of the contents of the 92-page work is pretty interesting, the book presented in eight sections (or "casualty classes programs"): (I) Attack Analysis Programs; (II) Vulnerability Analysis Programs; (III) Damage Assessment Programs (Direct Effects, sections dedicated to nuclear shots Dusty III, Flame I, Jumbo III, Streak IV, Dart II, Dart III, Picnic, Ready I.(IV) Resource Evaluation Programs; (V) Economic Analysis Programs ; (VI) Resource Management Programs; (VII) Mapping and Display; (VIII) Manual Procedures for Damage Assessment and Resource Evaluation. The last section describes programs of manual damage assessment ("developed by agency representatives for use when computer estimates are not available").
Under section III are described the various other programs computing availability of surviving resources and damages to the rest, and to assess capability and loss. For example: Weapons Edit III (working on an 1103 AS or 1105 computer) calculates missile availability; Dusty III (fallout intensity "...at weapon oriented points"; Flame I ("computes an estimate of the extent of the spread of uncontrolled fire") and can compute fire maps; Jumbo III (a casualty assessment program); Attack Environment III ("determines the blast effect from the dominant weapon and combines the separate effects of fallout and from from all weapons that affect each resource point"); Facility Assessment (Namepoint) III ( for physical damage to facilities); Time-Phased Accessibility ("listing of accessibility of resources in various conditions of damage after an attack"); Population III (summing up casualties in populations after attack; Manpower III (translating population losses into labor losses and how it would affect x,y, and z); Livestock III (keeping tabs on livestock "and livestock products"); Streak IV ('high speed estimate of blast and fallout casualties, estimates of damage and denial of facilities..."); Picnic (!, estimating casualties from biological or chemical weapons), and a number of other programs.
There are some other interesting programs for end game times: Net Inventory ("(a) routine (that) is a balance sheet between supply (inventory and production) and demands (requirements)" and Amounts of Production ("a routine (showing) the production based in facility damage and labor casualties; and of course Survival II, which computes "the total requirements...for regions".
Of course it was necessary to figure all of this stuff out so that in the event of The Big One there is a certain control over what is where and what is left and what is needed and so on.
There is no mention made to where these computers are housed.
It certainly seems that if there was to be a nuclear holocaust, it would be well-enumerated.
This is a duplicate of a carbon copy document by I.I. Rabi, and is one of 35 documents1 relating to the development of U.S. atomic policy, October 1945-January 1946, that comes from the library of Caryl Haskins2, a close and long-time friend of Vannevar Bush, who worked with Bush throughout World War II at the OSRD, and was executive assistant to Bush at NSRD 1941-1945. Vannevar Bush, one of the most important scientist-advisers of World War II, foresaw the development of the atomic arms race in 1943, and by 1945 became a fundamental thinker and advocate of addressing the problem of atomic information control. The 35 documents in this collection are--almost without exception--by aides and close colleagues of Bush who assisted him in formulating the positions and issues, dating from October 1945 through January 1946. They consist of background papers, drafts of proposals, informal studies, as well as mature statements of thought that would become implemented in the core of U.S. policy regarding the spread and control of atomic weapons. They are generally carbon typescripts and necessarily of extremely limited distribution, generally have no letterheads, occasionally carry the authors’ full names (although sometimes only initials are used), and 18 are stamped or typed “Secret”.
The sheet by Rabi (1898-1988) is simple but interesting, and in 53 words outlines the issues of the atomic bomb--it is dated November 21, 1945. IT was typed for Rabi by an assistant ("rb"), and at the bottom as being by Rabi. Rabi of course played key roles in the development of the bomb, as well as playing a very crucial and critical role in the discussion of the future of atomic weapons.
[These are the two copies of the Rabi outline--the second was Irving Langmuir's copy. There couldn't've been too many of these made--there would be the original, then perhaps six carbon copies. I any event, it is a rare thing. The original is for sale here at our blog bookstore.]
The sotto voce singing of the oblivious obvious/mundane is slung throughout the nearly 200pp-work "Mass Casualties, Principles Involved in Management", which were papers delivered at the 62nd annual convention of the Association of Military Surgeons, published in 1956 in Military Medicine.
How can a person--how can I--write about Nuclear Holocaust as being mundane? When it comes to reading how some people mundanely responded to planning for surviving it.
It is a very deep Disturbia into which people fall when writing about the millions of details in accounting for the unaccountable, writing about the medical/physical/psychical consequences of surviving a bomb when dozens might well be detonated at the same time, the millions of details overtaken by billions of other details not mentioned and perhaps not imagined.
I've collected some wide non sequiturs dealing with the matters of the nuclear apocalypse from a publication calledMilitary Medicine in an article entitled "Mass Casualties, Principles Involved in Management", which were papers delivered at the 62nd annual convention of the Association of Military Surgeons, 1956. Sometimes the chapter heading says it all, giving wide pause; and sometimes you have to wade in a little, but you don't need to go very far, or very deep. Overall the issue of the absolutely overwhelming devastation and the impossibility of dealing with the human consequences of nuclear war do absolutely get written about, but it occurs somewhere inside each contribution, which is front-loaded with pop-iconic understatement and then followed up with vast simplification.
Then of course there is the official-speak in quietly stating screamingly bad things: "a wide disparity will in all probability exist between patient load and medical resources". There's so much like that in this publication that it is hard to keep up, like differentiating sands on a beach.
[I resisted including the section on the use of dentists in the post apocalypse--it was too painful, and I ran out of steam.]
I kept this book mainly for the cover art, though the writer--William L. Laurence--did a commendable job of looking at the Hell Bomb (the hydrogen bomb) and provided a useful chronology at the end of the book for attempts at nuclear control. Laurence was a science writer for the New York Times and was also the official historian of the Manhattan Project--he was also about the first person to write for a mass audience on the coming of what he would eventually coin "the atomic age" in a 1940 NYT article1.
The book is agile but also a very slight read with not much detail, published without a single footnote, and without a bibliography, sort of like a long newspaper article. One thing is for sure though--he was right about the "hell" part.
1. "Vast Power Source in Atomic Energy". New York Times. May 5, 1940
Here's an interesting article on the popular reception of the possibilities of atomic power if not an atomic weapon, found in the NY Times, 1938-1940: http://ansnuclearcafe.org/2013/11/26/excitement-about-u-235-as-coal-competitor-circa-1939-1940/
[The preparation of the bomb, at center, before being quite armed and hoisted--(AP Photo/File)]
The "Princess and the Pea" comes to mind with this story, except that the pea was located above the mattresses, suspended from cable above them. It was the ultimate pea.
That "pea" was an atomic bomb. It was suspended in inside a 100-foot tall metal tower in the desert of Alamagordo, in the Jornado del Muerto, the test shot to see if the bomb worked, the near-culmination of the work of 100,000 people and billions of dollars, and the great potential decision-maker on the outcome of WWII
This was the Trinity Test--July 16, 1945.
The bomb was hauled up to its position in the tower, dangling there, not much protected from the elements which that night of the test threatened lightning and wind. What of the cables failed? And the bomb fell?
The last-minute fail safe was a large pile of mattresses. They would cushion the fall. The bomb would not explode, but it could be heavily damaged. And in this makeshift way the enormous investment was protected.
The bomb was detonated at 5:29 that morning, creating at 1100'-wide crater, causing the atmosphere around the explosion to turn blue from heavy radiation, and raising a 40,000'-tall mountain of smoke, a result of its 15kt yield.
The tower of course was vaporized.
I assumed too so were the mattresses--even if they were Army-issue.
It is a secret irony of some sort that while pre-detonation betting was going on by the scientists about the yield of the device with a side wager on whether or not the atmosphere would be set on fire, that the stop gap measure preotecting the bomb if it fell was a pile of mattresses.
[Oppenheimer and General Groves--standing too close for comfort--at the footings of the dissolved tower, afterwards, their whie footies in place for radiation protection.]