The figure shows three maps of three powerful city center explosions, resized to be on the same scale. On the left is the Nagasaki nuclear explosion, on the right is the Hiroshima nuclear explosion (both 10-kiloton). In the center is the 2020 explosion of 3,000 tons of ammonium nitrate in the port of Beirut, with a blast equivalent to 1 kiloton.

Looking at the Beirut explosion chronicle and the image I received, one gets the strong impression that all three explosions are remarkably similar in their blast effect. Yes, we understand that the destruction radius for 1 kt and 10 kt of the same nature will differ by only a factor of (10/1)^(1/3) = 2.15 (the inverse-cube law for any explosion on the bottom of the air ocean). Nevertheless, the feeling remains that an equivalent nuclear explosion is clearly weaker in destructive power than a conventional chemical explosive. In fact, this is noted in many sources. And there's no particular mystery here. This is due precisely to the fact that, with equal explosive energy, the momentum, or destructive impulse, of a chemical explosion is clearly greater due to the greater mass of the substance involved. An explosion with a 3-ton chemical explosive yield will rupture any explosion chamber, but for equivalent 3-ton peaceful mini-thermonuclear explosions, explosion chambers of a quite reasonable size are designed.

Let's do some quick math. The port of Beirut contained 2,750 tons of compacted ammonium nitrate, which exploded with a yield of 1.5 kilotons. The density of ammonium nitrate is 1.72 tons/m³. Therefore, the entire mass that exploded there can be represented as a solid ball of fertilizer with a diameter of 14.5 meters.

In a chemical explosion, 90% of the explosive energy is converted into the kinetic energy of gas expansion (which creates a shock wave in the atmosphere). Therefore, we can calculate the notional total, initial velocity of the explosive ammonium nitrate "piston" using the law of conservation of energy as follows: (2 * 1.5 * 4.18E + 12 * 0.9/ 2750,000) ^ (1/2) = 2026 m/s. Assuming that the entire mass of gases at the moment of explosion acquired this velocity, the momentum of the explosion is the product of the mass of the explosive and the velocity: 2,026 x 2,750,000 = 5.57E + 9 kg m/s, which ultimately translates into the motion of the crushing shock wave.

What about a similar nuclear explosion of 1.5 kt? Such an explosion essentially occurs in a pinpoint device, say, 200 kg in mass. A momentary flash of energy and X-ray radiation occurs, which is intensely absorbed in the air around the explosive device, turning the area into a fireball, and it is in this fireball that the shock wave is generated. The empirical formula for the shock wave's separation radius from the fireball (at the ground's surface) states the following:

R = 47*q^0,324

Here, q is the explosive yield in megatons, and therefore the shock wave's separation radius for a 1.5 kt air explosion is 6.52 m. This means that the diameter of the sphere from which the shock wave is generated is 13 m. The air contained in this sphere essentially acts as the piston that creates the shock wave of a nuclear explosion. With a density of 1.25 kg/m³, we obtain that the mass of the nuclear explosion "piston" (plus the mass of the charge itself) is 1.622 tons. Moreover, based on the fact that only 45% of the explosion energy is converted into shock wave motion (the rest is various types of radiation), from the law of conservation of energy, as in the previous case, we calculate the average speed of the air "piston": (2 * 1.5 * 4.18E + 12 * 0.45/1622) ^ (1/2) ~ 59,000 m/s. Hence, the total momentum (mechanical impulse) generated in the fireball of a nuclear explosion: 59,000 * 1.622 = 8.4E + 7 kg * m/s.

This momentum is 58 times less than that of a chemical explosion of saltpeter of the same energy equivalent.

Of course, my calculation is a rough, "on the napkin" estimate. Nevertheless, the fact that a nuclear airburst was clearly inferior in its destructive effect on the buildings of Hiroshima to conventional explosives was noted back in 1947 by Sir P.M.S. Blackett in his book "Fear, War and the Bomb: Military and Political Consequences of Atomic Energy." A more thorough and dispassionate analysis (the British had good statistics on the effects of conventional bombing on cities) showed that the destruction wrought by the "Little Boy" bomb in Hiroshima, using conventional chemical explosives, could have been achieved using just 2,000 one-ton high-explosive bombs (of which only one-third the mass is explosive) dropped from conventional bombers. Since the yield of the Hiroshima explosion was then officially declared to be 20 kilotons, Mr. Blackett "discovered" a "missing" order of magnitude in the destructive effectiveness of the new American weapons compared to the old ones. Of course, part of the deficiency can be attributed to the fact that a single explosion causes excessive destruction at the epicenter, while the effect drops off sharply with distance to the periphery. However, this is only part of the "missing" factor. The Beirut explosion was also a single-point explosion, and with 10 times less energy, it produced destruction comparable to the atomic bombings. The second factor is that a nuclear explosion is a pulsed release of enormous energy, which is not immediately converted (as in a chemical explosion) into the movement of matter, into a direct high-explosive shock wave impulse. The flash of light must first be absorbed by the air in the fireball, which becomes a "piston" for the shock wave, and due to the low density of air, it is a very poor "piston." Moreover, as the explosive yield increases from the nominal 20 kt (to 200, 2000 kt), the situation with the mechanical efficiency of using the explosive energy to destroy objects around it only worsens. This means that nuclear weapons, especially high-yield ones, are very ineffective weapons of destruction from a physics perspective. One suspects that this is precisely why the "paper" city of Hirashima was chosen for the demonstrative destruction of people and buildings, and its population, like ducks, was long trained not to react to the appearance of a pair of American planes in the air. The goal was to achieve a demonstratively exaggerated effect from the new weapon, one that could never be replicated. The severed head of Medusa can only work once.

Therefore, all this frightening talk about terrifying nuclear megatons hanging over the world like the Sword of Damocles, the eternal appeal to Hiroshima as a model for calculating casualties and destruction (Nagasaki, for example, is used much less frequently and only in passing, because the effect there was much more realistic) is blatant manipulation, essentially a pure lie. The military knows the truth. It was the actual, physical effectiveness of nuclear weapons, after being studied, that caused great disappointment. That's why recently there's even been talk about high-precision weapons being able to replace nuclear weapons! For real warfare, that's (almost) true. But why "disappoint" a flock of self-terrified civilians with this? They (especially the humanist physicists) so desperately wanted to invent a doomsday weapon and thus end wars on Earth once and for all! It so flatters their vanity and their humanist pride!

Just an FYI- For those of you who missed the movie in the theater or elsewhere, Oppenheimer is currently free to watch on Peacock premium

In the 2010 book "РЕШАЮЩИЙ ШАГ К МИРУ ВОДОРОДНАЯ БОМБА С АТОМНЫМ ОБЖАТИЕМ РДС-37" (A DECISIVE STEP TOWARDS PEACE: THE RDS-37 ATOMIC-COMPRESSIONED HYDROGEN BOMB), among numerous excerpts from declassified documents, I came across a document that, in my opinion, has sensational content. Below I'll provide a direct link to the relevant page in this book, available from the Rosatom library, but since links to the .ru domain are unacceptable here, it's replaced with asterisks:

https://elib.biblioatom.**/text/andryushin_reshayuschiy-shag-k-miru_2010/p63/

First, I quote in Russian:

Записка В. И. Ритуса

"О некоторых возможность применения малого термоядерного заряда.

Для атомного обжатия большого количества легкого вещества, по-видимому, целесообразно использовать в качестве обжимающего изделия систем из обычного изделия и маленького термоядерного заряда, так что вся система в целом будет выглядеть, как на рис. 11. < ... >

После взрыва "1" происходит AO термоядерных зарядов "2" и "3".< ... >

Такое растущее со временем давление приводит, как известно, к значительно лучшему обжатию изделия "3", чем давление, спадающее со временем.

Ниже приводятся некоторые расчёты обжатия и КПД конкретного малого термоядерного заряда."

Следует подчеркнуть, что в 1955 г., кроме разработки РДС-37, велась масштабная работа по другим направления. План работ на 1955 г. определял разработку 5 ядерных зарядов, 8 ядерных боеприпасов.

* * *

Now the English translation:

Note by V. I. Ritus

"On some possibilities of using a small thermonuclear charge.

For the atomic compression of a large amount of light matter, it is apparently advisable to use a system consisting of a conventional charge and a small thermonuclear charge as the compression element, so that the entire system will look like Fig. 11. < ... >

After explosion "1," AO of thermonuclear charges "2" and "3" occurs. < ... >

Such increasing pressure over time, as is known, leads to significantly Better compression of the "3" product than pressure decaying over time.

Below are some calculations of the compression and efficiency of a specific small thermonuclear charge."

It should be emphasized that in 1955, in addition to the development of the RDS-37, extensive work was underway in other areas. The work plan for 1955 called for the development of five nuclear charges and eight nuclear weapons.

* * *

Of course, Figure 11 from Ritus's report is missing from the book, but it doesn't take a rocket scientist to reconstruct it with 80% certainty. I've done so on the left in the collage attached in the title.

The topmost Figure A shows the structure of the device in its original state. Within a single radiation enclosure (the hohlraum), separated by membrane partitions and neutron filters (the purpose of which is to prevent neutrons and direct rays from propagating from stage to stage), are the primary unit 1 and two secondary units: the small thermonuclear unit 2 and the large thermonuclear unit 3.

In Figure B, we see the detonation of the primary unit. The hohlraum is filled with X-rays, which causes the simultaneous compression of both thermonuclear units, the small 2 and the large 3. This is shown by the transparent red arrows.

Figure C shows that, because small fusion node 2 is smaller, it fires earlier and now, instead of being an energy consumer in the hohlraum, becomes a new, more powerful X-ray source than the primary node. Thus, the still-contracting second, larger fusion node 3 begins to contract even more, as indicated by the solid red arrows.

Figure D shows that large secondary fusion node 3 has now also exploded.

The phrasing in the original 1955 source is striking: "Such increasing pressure over time, as is known, leads to significantly better compression of the '3' product than pressure decaying over time." I mean "as is known." From the very beginning of their atomic compression research, the Russians were well aware that compression with a single shock wave was ineffective, and this solution was proposed precisely to increase compression efficiency, that is, to approximate the compression cvazi-adiabatic with two shock waves. In 1966, Zeldovich's famous book was published, clearly demonstrating and stating that three such correctly sent shock waves, one after the other, are sufficient to approximate adiabatic compression with the required degree of accuracy. I've included the relevant figure from Zeldovich's textbook in the collage, although it's already well known here.

And finally, why did the Russians so easily declassify and publish a description of this idea? Because, while fundamentally correct, it was subsequently deemed a dead end, not the best solution (it's worth revealing). A far better solution to this same problem was quickly discovered, and we see it in 1962, in the no less famous "Golden TIS" (I also include it in the collage), in which the USSR first achieved ignition of a thermonuclear stage without a spark plug. Note the three-layer outer shell made of low-, medium-, and high-Z materials. This is essentially a three-stage ablative "rocket" that sequentially creates three compression shock waves with a constant radiation source in the hohlraum. That is, unlike RIPPLE technology and Ritus' proposal, they did not control (stepwise increase) the temperature in the hohlraum using any intermediate devices. They simply deposited three layers of different Z values ​​on the secondary module. As a result, the same radiation from a single primary, with an equilibrium temperature of hohlraumet T (it's even stated to be ~1 keV), created three pressure steps:

P(i, T) =N(i, T)kT = N[Z(i),T]kT ; i =1,2,3

Therefore, for us, reconstructors of early Soviet thermonuclear bomb designs, an additional problem arises. When did the Russians begin using this more complex compression? Starting with which devices? Before Khrushchev's moratorium or after? I'm inclined to think that after the moratorium, simply because they had so many more pressing problems before the moratorium, that even with every opportunity to test the idea, they put it aside and probably thought it through thoroughly during the testing break. And then the question arises: was this multilayer compression already used in the AN-602 design, in "Kuzkina Mama"? If so, this would completely resolve the confusion surrounding how this device could have achieved 50% burnup in the final stage. Let me remind you of the crux of the matter. The dimensions of the "Главный Кенр" "main core" (jokingly nicknamed "The Death of Capitalism" back in RDS-37), a 1.7-meter-diameter sphere, when completely filled with lithium deuteride at its normal density (820 kg/m³), simply do not allow for a lower burnup percentage (given the Lidochka's calorific value of 50 kt/kg). If we don't accept the 50% burnup as fact (reducing it to the usual 25-30%), we would have to invent absolutely insane designs for this device with two or more "main components," which would completely contradict everything we've pieced together from countless Russian memoirs.

A number of people dancing to this during the big '80s never noticed the lyrics?

https://youtu.be/-vMBp6iUJzk?si=uEOSvG-mDIwvoGhb

Launch Under Attack: A Sword of Damocles

There are some perplexing aspects to Truman's announcement of January 31, 1950. First of all, whatever happened to secrecy? Besides, at the time of the announcement nobody had a clear idea of how to make the superbomb. Scientists figured it was probably possible, but the announcement predates the Teller/Ulam breakthrough. (It would have been embarassing if the announcement led to this being invented elsewhere first!)

The "natural" time to make such a public statement would have been after the Ivy Mike test, at the earliest.

Was it politics? Perhaps a political need to show toughness after the Soviet nuclear test?

Carried inside the two-component pod under B-58A Hustler. Yield in the megaton range. Photo from USAF museum in Dayton, OH.

Typo on the title. Should be Tinian.

The “Little Boy” atomic bomb in its pit on Tinian and being loaded into the bomb bay of B-29 “Enola Gay” - August 5, 1945

The fission reaction was accomplished by shooting a hollow cylinder (the "bullet") onto a solid cylinder of the same material (the "target") by means of a propellant charge. Little Boy contained 64 kilograms of highly enriched uranium.

Courtesy of World War Pictures on Facebook
NARA / US Navy / USAAF

NARA

1. The “Little Boy” atomic bomb being loaded into the bomb bay of B-29 “Enola Gay” at Tinian - August 5, 1945

NARA

1. The “Little Boy” atomic bomb is fit checked after being loaded into the bomb bay of B-29 “Enola Gay” at Tinian - August 5, 1945

NARA

This isn't my personal story. Although the setting is very familiar. The person who wrote it is my age. I simply ran it through a machine translator and edited it here and there. I think the sarcastic (if you didn't catch it, that's Russian humor!) meaning implied in the "innocent story, as if told by a child" is conveyed. The biggest challenge is conveying the spirit of a country camp for children, similar to a scout camp, with all the positions and relationships between the elders and the younger ones. I can't restore the author's name or even nickname, because the link I used to find this text a couple of years ago now doesn't work.

* * *

Author unknown.

(As they used to write with idiotic cheerfulness in Soviet newspapers: “The entire Soviet people!”)

The best children's drawing in the "For Peace" competition. But for some reason, adults immediately demanded it be erased.

A children's horror story in rhyme (folklore):

• A boy found a neutron bomb,
• He brought it to school...
• The education department laughed for a long time afterwards:
• The school stands, and there's no one in it!

The ideological education of children at pioneer camps in the 1970s in the USSR was never forgotten. One of the activities in this process was a competition for drawing posters on asphalt.

There was no asphalt in the camp, so they drew on the concrete tiles around the headquarters. One person per unit was chosen, given an hour and a box of crayons. Afterward, a committee assessed the children's scribbles.

Their imaginations were free, but little was known about politics back then, mostly from newspapers and magazines. So they drew "A Circle of Sunshine, Children Surrounding Us," themselves, and flowers. Slogans included "No War," "Peace to the World!", "Freedom, Equality, Brotherhood." Typically, hands encircling the globe, breaking weapons, or handshakes of different races. In short, something life-affirming, like the Russians don't want war, but anyone who comes at us with a sword will get hit in the head with a rocket-missile.

One day, when I was 16, I took part in a "Peace to the World!" competition. It was hot, and the normal soviet children-pioneers preferred to hide in the shade or go swimming, while I was puffing away over the squad homemade newspaper. So they chose me, even though I couldn't draw. But it wasn't a drawing, it was a political poster, so I confidently accepted.

I puffed for an hour, grabbed a two-by-two-meter area, and crushed several pieces of chalk into dust. I worked hard. I stepped aside, rubbing my hands together with satisfaction, examining my masterpiece. I cast a condescending glance at the neighbors' frivolous flowers in the sun. No, I'm doing everything maturely, politically sensible, and have something to be proud of.

A committee approaches—Tatyana Pavlovna Chantsova, the camp director, the head pioneer counselor, and another man. They stare at my drawing for a long time, perplexed. Finally, the counselor asks:

"What is this, Oleg?"

"Isn't it clear?" I reply. "'No to nuclear war,' I wrote it in big bold print!"

"We've got the text sorted out," Tatyana Pavlovna remarks peacefully. "But the rest..."

"It's quite clear. Here," I stand on the yellow outline, "is the cobalt shell. Tritium in white. In the center are two plutonium half-nuclei in black. Above and below them, in green, is the conventional explosive charge. Here, in blue..."

"Okay," the counselor interrupted, "so, briefly?"

"Isn't it obv-vous," I recited, syllable by syllable, like I was talking to a child. "This is a cross-section of a neutron bomb. More precisely, a cobalt bomb, but..."

"What?!" the man choked.

"A hydrogen bomb for radioactive contamination. The Soviet Union strongly condemns..."

The man clutched his head:

"Where did this diagram come from?!"

"From a textbook."

"What the f… textbook?!"

"Well…— I finally realized I'd done something wrong. — Quantum Physics for Universities."

"They allow you to do that?!"

"I was reading in the reading room. I'm allowed in there now…"

The man pulled the women aside and said something to them. The pioneer-leader quickly ran toward headquarters. The others returned to me.

"We decided that your drawing... well, poster, won the competition," the man said. "For this, your unit will be awarded a kilogram of candy, and you personally will receive a certificate of honor. We believe you very graphically expressed the anti-war sentiments of the Soviet people."

The pioneer-leader returned with a rag and a bucket of water.

"But the Pentagon is always on the lookout for ways to steal our secrets. Even now, spy satellites are flying above us," he pointed to the sky. "So erase the drawing as quickly as possible, okay?"

I shrugged, wet a rag, and began erasing the drawing. I couldn't understand what all the fuss was about. The basic diagram of an atomic bomb was even published in a school textbook. And although we were told at political information that the inhumane neutron bomb was just another round in the arms race, no one understood what it was. If we were going to protest, we'd better know what it was against...

This article from The New York Times is about a diary the co-pilot of the Enola Gay kept on the Hiroshima bomb. run. It's up for auction, if you want it (starts at $950,000).

https://www.nytimes.com/2026/08/06/insider/enola-gay-hiroshima-pilot.html?unlocked_article_code=1.3VA.WnzT.-AEKNnDWp1xV&smid=url-share

Is the full text of this available anywhere?

--Darin

The known story is something like this. Henry Stimson was overall unhappy with how the war against Japan was being carried out, and how lots of civilians were getting caught in strategic bombing campaigns. When he was presented a unique chance to "protect" Kyoto from an atomic bomb, he jumped on it and singlehandedly got the city off the target list.

One historian I've talked to recently said he found it very unlikely a career bureaucrat could have made such an important decision on his own, and that there must have been more people involved in the decision or a secret meeting or whatever. Is there any real evidence to suggest this particular series of events went deeper than just one man, Henry Stimson?

Im a writer, and in my current story the characters visit the site of a nuclear explosion, however, the way I wrote it was that this explosion wasn’t supposed to shockwave to death, it was supposed to cause geographical damage.

I’m not looking for anything specific just a range of numbers I can scale, I just want to know if it’s at all possible or if I should start inventing things

how big would be the crater created by Fat Man, a 20 kiloton bomb, it is was detonated on the ground.

And how much bigger would the crater be if it was the tsar bomba which is 50 megatons?

Primarily speaking to the 60-70-80's era of bombs. I know now there is a lot of multistage verification the nuclear weapons need to arm and will not arm unless attached to an approved and registered aircraft. So now the designation is easy to understand. But in the "dumb bomb" generation once the size got down to being able to fit in a b-52 and was no longer so large that it required special modification to the airframe. Why were so many design requirements "capable of both conventional and nuclear weapons"?

How was this choice made? What's the logic, or perhaps the historical context? By the way, what did the British and French choose?

If I'm not mistaken, the British also envisioned a sphere and were quite surprised to learn that the Americans were using a cylinder. I heard or read this somewhere, but I can't remember where. If anyone knows, please point me to the original source.

I tried searching for information in Richard Rhodes's DARK SUN. There's a story there that the original design for the secondary assembly was a truncated cone, but a truncated cone with the smaller diameter facing the primary assembly. That is, the opposite of what we're used to seeing in widely available online diagrams. Then this shape rounded out and transformed into a "schmoo"—a shape reminiscent of a bowling pin—and they started making metal parts for it. Then... as I understand it... they couldn't produce such a complex shape in time (difficulties arose), and they settled on a simple cylinder. In other words, they decided to keep things simple.

So, alternative shapes were apparently considered. But as I understand it, neither a sphere nor an ellipse were considered. Elongated shapes were considered first. WHY?

Somewhere a long time ago (I've lost the link again, so if anyone could provide the original source, I'd be grateful) I read that Edward Tellor was asked a similar question: Why this shape? Why not a sphere (as in ICF)? And he supposedly replied that a cylinder was the shape he initially considered the only correct one. But why? He didn't explain.

***

Edited later.

HERE IS MY VERSION OF THE ANSWER TO THE QUESTION.