Uranium cubes reveal why the German nuclear project failed

(arstechnica.com)

153 points by rbanffy3 days ago

10 comments

leonidasrup14 hours ago
Boron contamination of graphite also slowed the Manhattan Project:" Fermi writes that "The results of this experiment was [sic] somewhat discouraging" presumably because of the absorption of neutrons by some unknown impurity. So, in December 1940 Fermi and Szilard met with Herbert G. MacPherson and V. C. Hamister at National Carbon to discuss the possible existence of impurities in graphite. During this conversation it became clear that minute quantities of boron impurities were the source of the problem. "<a href="https://en.wikipedia.org/wiki/Nuclear_graphite" rel="nofollow">https://en.wikipedia.org/wiki/Nuclear_graphite</a>
- qnleigh9 hours ago
 This is why the German's used heavy water instead of graphite as a neutron moderator, which made it much harder to build a reactor. Their early reactors consisted of concentric spheres of heavy water and uranium powder. This was an unfortunate combination, as uranium powder ignites on contact with water. Leaks caused explosions on two separate occasions [0].In contrast, the first allied nuclear reactor was a literal pile of uranium and graphite on a squash court.[0] The Bastard Brigade (great book on all of this)[1] <a href="https://en.wikipedia.org/wiki/Chicago_Pile-1" rel="nofollow">https://en.wikipedia.org/wiki/Chicago_Pile-1</a>
 - stymaar5 hours ago
 > uranium powder. This was an unfortunate combination, as uranium powder ignites on contact with water.Why did they use metallic uranium instead of the stable oxide?
 - Kubuxu2 hours ago
 Pure guess based on intuition: density making it easier to reach criticality.
 - 44mkultra691 hour ago
 > This is why the German's used heavy water instead of graphite as a neutron moderatorWere there other approaches discussed or used in Germany around the time?
- schiffern12 hours ago
 Sounds like a good time travel story: the mission is to go back in time and plant a single uranium cube, to be found ~80 years hence, to convince people that the German bomb project was doomed so that– ahh, but let's not spoil it! :)
 - barrenko16 minutes ago
 Never ever do I read enough about the blame Europe had in all of this due to it's procrastinating to deal with Hitler / Germany on time.Happening again with Russia.
 - TomJansen12 hours ago
 So that WW2 had to go on for an extra 2/3 years?
 - xbmcuser9 hours ago
 Germans had already surrendered and the Japanese were going to surrender as Russians now were able to move their force against Japan before the nuclear bombs were used. They were used to test the bombs and make sure no such war happens again specially the 2nd Bomb on Nagasaki that was used a few days after they bombed Hiroshima.
 - defrost9 hours ago
 > They were used to test the bombs and make sure no such war happens againThe two cities were already on a "to be bombed" list and were the 73rd and 74th Japanese cities to be utterly destroyed by bombing.So, Yes - they were literally used to test the bombs.The "and make sure no such war happens again" is more of a post WWII retcon of the Cold War era.
 rightnutwingjob8 hours ago
 In all likelihood, the two nuclear bombs killed fewer people than the bombing that otherwise would have occurred.
 lazyasciiart5 hours ago
 What, if Truman had accepted the telegram surrender instead of sending nukes in response?
 defrost8 hours ago
 Really?They certainly killed less people than the bombing that had already occurred - the destruction of Tokyo alone likely killed more people than either atomic bomb.There's no real consensus in the alternative history conjecture space, and no way to resolve the theories floated, Gar Alperovitz (for one example) made the argument that<pre><code> * that Japan was already defeated at the time the decision to use the bomb was made, and that US intelligence already knew this; * that Japan had been suing for peace and was ready to surrender without an invasion; * that the real reason the bomb was used was so to demonstrate its power to the Soviet Union, in an attempt to exert more influence on them in the postwar; * and that Japanese Emperor’s surrender statement invoked the bomb only as a politically-acceptable “excuse” for his people, when actually he surrendered primarily because of the Soviet invasion of Manchuria. </code></pre> ( in <a href="https://www.amazon.com/gp/product/B004FGMR3S" rel="nofollow">https://www.amazon.com/gp/product/B004FGMR3S</a> )
 hunterpayne8 hours ago
 This is alternative history, not real history. Remember, there was an attempted coup even after the first bomb to prolong the war. The Japanese leadership at the time were very zealous verging on religious zeal. One of the things that got them to eventually give up was a captured US fighter pilot that (under threat of death) told the Japanese that the US had 100s of atomic bombs. This was a lie but he didn't know that and just was trying to get the insane intelligence agent to not cut his head off (literally). There were other factors too. The USSR invading Manchuria for example. Also the US was in the process of ringing the home islands with 50 fleet carriers (the big ones, 50kt displacement) which would have been able to bomb Japan at will. Even with all of this, there was a significant faction of Japanese leadership who wanted to fight on.These claims are more about politics than anything. Its an attempt to retcon history to vilify the US. The Japanese had never been invaded and that was a huge point of pride. They were training the civilians for a guerrilla war. Just because you can find a person in the Japanese government who wanted to surrender at that point (and there were) doesn't mean that's the decision that would have been taken.PS That 3rd point is especially specious...if it were true, no 2nd bomb would have been used. PPS Stuff like this is why historians don't like nor will engage with hypotheticals or the alternative history folks. Its clearly politically motivated, not a good faith attempt to understand history.
 fc417fc8027 hours ago
 > Its an attempt to retcon history to vilify the US.An attempt to vilify ... the side that eagerly deployed nuclear weapons on civilian targets? I'm from the US and I'm not someone who is blind to pragmatism but your argument here just seems completely absurd to me. We clearly committed an atrocity with somewhere between minimal to no legitimate justification.Then again, after seeing the adjacent comment about avoiding soviet involvement it occurs to me that perhaps we inadvertently did them a favor in a roundabout way. Japan probably would have lost a lot more than the kuril islands otherwise.
 philipallstar1 hour ago
 > the side that eagerly deployed nuclear weapons on civilian targetsNo one was eager. This sort of lie destroys discussion. This site is only about discussion, so please don't keep trying to destroy the only thing the site is about.
 nickff7 hours ago
 Where did you get the idea that the USA was “eager” to deploy the atomic bomb?>Stimson wrote in his diary afterwards that after his briefing, Truman felt “the terrible responsibility that such destruction placed upon us here and himself.” [1][1] “Memorandum of Conference with the President, August 8, 1945 at 10:45am,” in Stimson diary (8 August 1945), Henry Lewis Stimson Papers (MS 465), Manuscripts and Archives, Yale University Library.
 fc417fc8026 hours ago
 For starters, how many days did it take before we dropped the second one again? I don't think it matters what any of the participants wrote or said given the events that we know to have transpired. There were clearly many other paths available to take.
 somenameforme2 hours ago
 Truman's own diary would be a pretty good source: <a href="https://nsarchive.gwu.edu/document/28466-document-47-trumans-potsdam-diary" rel="nofollow">https://nsarchive.gwu.edu/document/28466-document-47-trumans...</a>The diary is full of revealing quotes like "Discussed Manhattan (it is a success). Decided to tell Stalin about it. Stalin had told P.M. of telegram from Jap Emperor [actually from the Foreign Secretary] asking for peace. Stalin also read his answer to me. It was satisfactory. Believe Japs will fold up before Russia comes in. I am sure they will when Manhattan [A-bomb] appears over their homeland. I shall inform Stalin about it at an opportune time."For some timeline the US had secretly arranged for Russia to declare war on Japan on August 8th. We nuked them first on August 6th, and then again on the 9th. The goal was to get them to surrender to the US before the Soviets made significant inroads in Japan.
 Lum248 minutes ago
 « The diary is full of revealing quotes »Do you think what they reveal is the truth? Was the diary meant to be published and become "a source"? Was Truman informed about everything important going on in the US? About the reality (the truth) of the Manhattan Project? Did he even need to know? Wasn't it preferable for him to simply believe in order to play his role?Just some questions to ponder as to the quality of this source and what can be deduced from it.
 TheOtherHobbes51 minutes ago
 The bombs were an atrocity against a nation that had been committing atrocities of its own.There are no moral winners in war.But it remains true that if Japan or Germany had had the bomb, they'd have bombed civilians without compunction, discussion, or regret.
 wombatpm6 hours ago
 The second bomb is the one whose use is questionable. If Truman were to be tried for war crimes it would be for that. A surrender was in play. Truman wanted no conditions. I think another week of people dying from radiation poisoning would have brought people around anyway.
 refurb3 hours ago
 This theories all fall flat when Japan refused to surrender after the first bomb. As the other comment mentioned there was an attempted coup to keep the war going.It took two bombs to get Japan to surrender. “A surrender is in play” means zilch.
 asanineassasin2 hours ago
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 Lum21 hour ago
 [repost b/o deletion/suppression]« This is alternative history, not real history. »Okay, but "real history" is full of lies, so that per se cannot be an argument against "alternative history". Which is not to say that "alternative history" is truthful, it can be just as full of lies, or even, in certain cases, be the flip side of the very same lie.Your fighter pilot anecdote sounds like Hollywood: Good US boy scared to death by insane fanatical Japanese cranks up a lie that is then believed by the highest state leadership, alright… We can smell the propaganda here, can't we.What defrost said wrt Alperovitz sounds very reasonable:• Japan already defeated – FACT• Japan had been sueing for peace (since around May, I think) – FACT• real reason for "The Bomb" was to impress Soviet Union (and the world at large, I think) – FACT• "The Bomb" only an excuse for emperor, real reason was Manchuria – arguable/doubtful, but not important; key is points 1 and 2Now, in his book "Hiroshima revisited" (free PDF available), Michael Palmer takes a scientific look at the Hiroshima and Nagasaki evidence and concludes that it does not support the notion conveyed by US propaganda that a novel "atomic bomb" was used.†Rather, it appears these cities were democratically firebombed like dozens of other Japanese cities, using napalm, which is clear as day from the medical evidence. Palmer, who is an MD, also notes that there is a conspicuous absence in the medical literature about napalm injuries.In fact, the forensic evidence (medical, physical and other) totally and absolutely contradicts the notion that any extraordinary weapon such as the "atomic bomb" was used.But there was more than napalm (a heinous weapon) that was dumped on Hiroshima and Nagasaki (like on dozens of other cities before). Various "special effects" were used, and notably mustard gas, apparently to fake radiation effects.† [URL deleted in this repost (in an attempt to avoid automatic censorship) but you can easily google it yourself]
 Lum22 hours ago
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 kstenerud6 hours ago
 Such a convenient narrative. "Yeah, a shit ton of civilians who weren't vaporized died slow, agonizing deaths from radiation exposure, but believe you me, it's more humane than the alternative! They should be thankful!"
 leonidasrup5 hours ago
 There is nothing humane in bombing with conventional explosives, or bombing with napalm, thermobaric weapons or nuclear bombing. Or biological or chemical weapons.<a href="https://en.wikipedia.org/wiki/Effects_of_nuclear_explosions" rel="nofollow">https://en.wikipedia.org/wiki/Effects_of_nuclear_explosions</a><a href="https://en.wikipedia.org/wiki/Effects_of_nuclear_explosions_on_human_health" rel="nofollow">https://en.wikipedia.org/wiki/Effects_of_nuclear_explosions_...</a><a href="https://en.wikipedia.org/wiki/Thermobaric_weapon" rel="nofollow">https://en.wikipedia.org/wiki/Thermobaric_weapon</a>
 CamperBob26 hours ago
 It was more humane, whether you like it or not. What if we had waited to learn our lesson until the Korean war, when the yield of the first atomic bomb dropped on people would have been measured in hundreds of kilotons instead of tens, and with a few hundred more bombs where that one came from?Also, people who are ready to surrender don't need to be nuked twice.
 kstenerud6 hours ago
 “The question arose: what about the women and children? I decided to find a perfectly clear solution to this too. I did not consider myself justified in exterminating the men — that is, to kill them or have them killed — while letting avengers in the shape of their children grow up for our sons and grandchildren.”- Heinrich Himmler“I am persuaded that this is a righteous judgment of God upon these barbarous wretches, who have imbrued their hands in so much innocent blood; and that it will tend to prevent the effusion of blood for the future, which are the satisfactory grounds to such actions, which otherwise cannot but work remorse and regret.”- Oliver Cromwell“It was no longer a question of merely dispersing the crowd, but one of producing a sufficient moral effect, from a military point of view, not only on those who were present, but more especially throughout the Punjab.”- Brigadier-General Reginald Dyer
 CamperBob25 hours ago
 "I wasn't there."- kstenerud
 defrost6 hours ago
 > people who are ready to surrender don't need to be nuked twice.The question remains whether in fact Japan "needed" to be nuked even once - it's unknown whether the ongoing city by city destruction would have resolved WWII.Further, did they "need" to be nuked a second time so quickly (within three days)? That second nuke was not to force a surrender (just as the first wasn't) - the two bombings were two live tests of two separate weapon designs untested in the field of war.
 CamperBob25 hours ago
 Further, did they "need" to be nuked a second time so quickly (within three days)?Apparently so. Most people will run up the white flag after being nuked once, you see.It was important to make them think that we had a whole stockpile of them. Otherwise, twice might not have been enough.
 - refurb3 hours ago
 If Japan were going to surrender, why did they refuse to surrender after the first bomb? And took days to surrender after the second bomb?The theory makes no sense
 maratc2 hours ago
 Japan were not going to surrender. Some things happened that made them reconsider.The things that happened: (a) Hiroshima bombed on Aug 6th, (b) USSR declared war on Japan and invaded Manchuria on Aug 8th, and (c) as the Cabinet gathered on Aug 9th to discuss the terms of surrender, Nagasaki was bombed.
 Lum230 minutes ago
 And if "the Bomb" was so overpowering and decisive, as immediately claimed by US propaganda, then why did the US attack again on Aug 14/15, using pumpkin bombs¹, in a " Grand Finale" ?Here's Yozo Kudo, general secretary of the Japanese National Association for the Assessment of Air Raids and War Damage:————————INTERVIEW: Why U.S. air raids continued until day of Japan’s surrender — THE ASAHI SHIMBUN² — August 14, 2023 — Yozo Kudo, 73, secretary-general of the national association of groups recording air raids and war damageThe United States carried out air raids from Aug. 14 to early Aug. 15. More than 1,000 aircraft, including 825 B-29 bombers, attacked targets nationwide. It is believed to be the largest number of aircraft deployed for (a string of) air raids during the Pacific War.Q: Which cities were attacked?A: Targets included Osaka, where Osaka Arsenal and Kyobashi Station were bombed, Akita’s Tsuchizaki district, Isesaki in Gunma Prefecture, Kumagaya in Saitama Prefecture, and Iwakuni and Hikari in Yamaguchi Prefecture.When small-scale bombings are included, about 30 locations were attacked. Many people were killed. But casualty counts vary, and the exact number is unknown.Q: Why were air raids conducted on the day of the surrender or the day before?A: Japan’s delay in accepting the Potsdam Declaration was in the background.The government informed the Allied powers on Aug. 10 that it would accept the declaration on condition that the emperor’s rights of sovereignty would not be changed. But arguments within the government and military became tangled over a response from the Allied powers. Some said the emperor’s status was not guaranteed, and an agreement was not reached for some time.The United States on Aug. 10 stopped air raids on urban areas by B-29 bombers to prevent an adverse impact on peace negotiations. The following day, air raids by B-29 bombers were suspended altogether.The United States once waited for an end of peace negotiations, although it continued some air raids by other bombers. But Japan did not produce its conclusion for some time, and the United States decided to carry out large-scale air raids on Aug. 14-15 to urge Japan to accept the Potsdam Declaration.Henry Arnold, commander of the U.S. Army Air Forces, had wanted the grandest possible finale, according to a history of warfare by B-29 bombers.The U.S. military initially considered an air raid on Tokyo, which would have a strong psychological impact on the Japanese government, but eventually decided to target several areas outside Tokyo.Japan decided to accept the Potsdam Declaration at a meeting in the presence of the emperor on Aug. 14. But it took time before U.S. military officials on the ground were informed of Japan’s decision, and air raids continued until the early hours of Aug. 15.————————That doesn't give a clear answer as to the motivation of these anewed US terror bombing raids against civilians. There is no military reason, as with all previous attacks on civilians. Just sadism? Or maybe the raids on Hiroshima and Nagasaki were not impressive enough?1 <a href="https://de.wikipedia.org/wiki/509th_Composite_Group" rel="nofollow">https://de.wikipedia.org/wiki/509th_Composite_Group</a>2 <a href="https://www.asahi.com/ajw/articles/14980968" rel="nofollow">https://www.asahi.com/ajw/articles/14980968</a>
 - somenameforme9 hours ago
 The USSR declared war on Japan on August 8th, as part of a secret agreement with the West. The US knowing this, first nuked Japan on the 6th and then again on the 9th. It's hard not to see 'us' as trying to force a surrender before the USSR could get significantly involved. Why? Because territories in WW2 were split up in significant part based on who conquered which part. Hence East Germany going to the USSR and West Germany going the the West. Thanks to the US getting a quick surrender from Japan, the USSR was able to be completely excluded from the following occupation of Japan.If any documents were ever created about this debate, they've probably been destroyed, and those involved have taken it to the grave with themselves. So I suppose technically we can never know for sure. But I think the cynical view is far more well supported. Or at least I think the cynical aspects were the majority of the logic behind it. And it was not only about control of Japan but also about sending a message to the USSR as the US undoubtedly saw the outlines of a new West-East world order emerging after WW2. And all the way up until the 80s [1] our dominant political philosophy was that we could win by intimidation and demonstrations of force, nuclear in particular.------------Wow, loving LLMs when digging into topics now a days. GPT was able to direct me to Truman's diary entries which are public record. [2] I take back the weasel wording above. Truman himself was quite clear on his intention and desires:"Discussed Manhattan (it is a success). Decided to tell Stalin about it. Stalin had told P.M. of telegram from Jap Emperor [actually from the Foreign Secretary] asking for peace. Stalin also read his answer to me. It was satisfactory. Believe Japs will fold up before Russia comes in. I am sure they will when Manhattan [A-bomb] appears over their homeland. I shall inform Stalin about it at an opportune time."- President Harry S. Truman, July 18th 1945[1] - <a href="https://en.wikipedia.org/wiki/Proud_Prophet#Impact" rel="nofollow">https://en.wikipedia.org/wiki/Proud_Prophet#Impact</a>[2] - <a href="https://nsarchive.gwu.edu/document/28466-document-47-trumans-potsdam-diary" rel="nofollow">https://nsarchive.gwu.edu/document/28466-document-47-trumans...</a>
 - rdtsc8 hours ago
 > Why? Because territories in WW2 were split up in significant part based on who conquered which part. Hence East Germany going to the USSR and West Germany going the the West.That was particularly painful for Churchill to accept at the end when he had to hand over Poland to Stalin. Poland was the reason Britain officially entered WW2 in 1939<a href="https://en.wikipedia.org/wiki/Western_betrayal" rel="nofollow">https://en.wikipedia.org/wiki/Western_betrayal</a>> We and France are to-day, in fulfillment of our obligations, going to the aid of Poland, who is so bravely resisting this wicked and unprovoked attack upon her people. We have a clear conscience. We have done all that any country could do to establish peace, but a situation in which no word given by Germany's ruler could be trusted and no people or country could feel themselves safe had become intolerable. And now that we have resolved to finish it, I know that you will all play your part with calmness and courage(Chamberlain, Sep 3, 1939)
 - Create4 hours ago
 > shall inform Stalin about it at an opportune timeStalin was fully aware well before Potsdam, Kurchatov was already working on it for years.
 defrost3 hours ago
 Some of the key technical people recruited into the Manhattan Project were already long time Soviet sympathisers and feeding updates on their work (and of others) back to the USSR.eg: (one of several) <a href="https://en.wikipedia.org/wiki/Klaus_Fuchs" rel="nofollow">https://en.wikipedia.org/wiki/Klaus_Fuchs</a><pre><code> Post Cold War declassified information states that the Russians freely acknowledged that Fuchs gave them the fission bomb. </code></pre> The case could be made for Stalin being better informed for a greater period of time than Truman (who was only read in to project in 1945 aft moving from VP to POTUS).- <a href="https://ahf.nuclearmuseum.org/ahf/profile/harry-truman/" rel="nofollow">https://ahf.nuclearmuseum.org/ahf/profile/harry-truman/</a>
thisisauserid3 days ago
This is central to the plot of D: Heavy Water, Neal Stephenson's second installment of the Bomb Light Trilogy.
- abcd_f3 hours ago
  Can it be read standalone or it needs the first book?
  - arethuza1 hour ago
    I'd recommend reading the first book before D.
- the__alchemist13 hours ago
  Holy shit this is out? I went to the book tour for Polostan. Ordered; ty!
  - mjmvisser11 hours ago
    Enjoy, it’s riveting!
mauvehaus11 hours ago
Since Norsk Hydro was mentioned in the article, I have to mention in turn one of my favorite books ever: The Winter Fortress by Neil Bascomb. It's the true story of the Norwegian commando sabotage of the heavy water plant. Short version: after a failed attempt by the English, some locals who'd fled to England and received training parachuted in, blew it up, and then skied to neutral Sweden. Legends, the lot of them: they froze their balls off and didn't have enough to eat, but they pulled it off.Every time I re-read it, it makes me want to take up nordic skiing. It is absolutely up there on my list of greatest true stories ever told with Touching the Void, The Emerald Mile, and a select few others.<a href="https://www.abebooks.com/Winter-Fortress-Epic-Mission-Sabotage-Hitlers/32355957550/bd" rel="nofollow">https://www.abebooks.com/Winter-Fortress-Epic-Mission-Sabota...</a>
- rjsw10 hours ago
 One of the Operation Gunnerside members was later part of the Kon-Tiki Expedition [1].[1] <a href="https://en.wikipedia.org/wiki/Kon-Tiki_expedition" rel="nofollow">https://en.wikipedia.org/wiki/Kon-Tiki_expedition</a>
- 112358132110 hours ago
 That looks good; thanks. Growing up, I loved the firsthand account published in the 80s. Probably mentioned as a source in this newer book. <a href="https://www.goodreads.com/book/show/100634.Skis_Against_the_Atom" rel="nofollow">https://www.goodreads.com/book/show/100634.Skis_Against_the_...</a>
 - mauvehaus9 hours ago
 I am so excited to read this; thank you! I've reread The Winter Fortress every year or two since the first time.
- mnw21cam3 hours ago
 Also the 1965 film "The Heroes of Telemark", the documentary "The Real Heroes of Telemark" by Ray Mears, and his book of the same name.
- qnleigh9 hours ago
 This story is also covered in The Bastard Brigade, which details many other Allied attempts to sabotage the Germany nuclear program. Fun fact: Heisenberg was close to being assassinated by a famous baseball player (Mo Berg). Very entertaining and interesting book.
 - hunterpayne7 hours ago
 There's a movie about that which focuses on Berg who was a pretty impressive person. He was a MLB player at a time when that was the biggest sport in the US but the players made next to nothing. He also spoke 10 languages fluently and spent most of the war translating intelligence intercepts. Supposedly he found Heisenberg but judged that he wasn't a threat and so didn't kill him. That's the story anyway, no idea how true that is.
- mk_stjames7 hours ago
 Little extra fun fact since Norsk Hydro was mentioned in the article and now you've mentioned it again-Norsk Hydro was founded as a hydro power plant + nitrogen fertilizer production company (the nitrogen production needing lots of electricity, and the hydro plant to provide said energy...) but around WWII, pivoted to light metals, and built aluminum and magnesium factories with German company IG Farben, in order to support them in the war, as they were partially under Nazi occupation by then. That all went south but then after the war they kept on with the aluminum business.The company went on to become experts in aluminum extrusions, and were then contracted not just for the base metal but also to manufacture the first bonded aluminum bare chassis for the S1 Lotus Elise in 1995, which went on to be the basis for the Tesla Roadster.
- testing2232111 hours ago
 Nordic skiing is great.As a snowboarder I was reluctant, but got into it a few years ago. We pull our young daughter in a chariot with skis about 10km into a little cabin by a river with a wood stove.Cheese, salami and hot chocolate and we make the return loop. Three evenings a week all winter long is a great way to spend time outside.
raldi11 hours ago
Clickbait antidote: The cubes revealed only that the uranium was a bit less dense than textbook values because of tiny internal voids.That measurement fed a computer model, but if I'm reading the article right, most of the work was actually based on wartime records on heavy water and graphite. Anyway, the model showed they would have needed twice the uranium and heavy water they actually had.
- hunterpayne7 hours ago
 It should be noted that they didn't have the supplies for the design they tried. There were designs that could have worked with what they had. And its unlikely that during the war anyone knew exactly which designs the Germans tried and even less chance that someone would have known if a specific novel design would have worked. Its an interesting detail but largely irrelevant.Its also suspected Heisenberg didn't want the design to work (its the given reason why he wasn't killed by Berg). But it was still a reasonable possibility during the war that the Germans could have made it work.
- Crunchified10 hours ago
 IIRC, US Colonel Hogan got Luftwaffe Colonel Klink to drink a bunch of that heavy water as a cure for baldness as a truckful of it transited through Stalag 13.Phew, that underground mission was more important than I thought!
mannyv6 hours ago
Anyone interested in the bomb should read 'And the Devil Reached Towards the Sky, an oral history of the atomic bomb.'It's full of fun anecdotes and asides...like when they 'found' tuns of uranium ore in NY...or the aforementioned acquisition of silver from Treasury.There are classic bureaucratic things...like when they issued a check for millions and specified 'no questions asked.' Then the guy called with questions. Or how Groves' people and Treasury tried to figure out how many ounces were in a ton.
- leonidasrup6 hours ago
 Also very good reading on this subject is "The Making of the Atomic Bomb", by "Richard Rhodes".<a href="https://en.wikipedia.org/wiki/The_Making_of_the_Atomic_Bomb" rel="nofollow">https://en.wikipedia.org/wiki/The_Making_of_the_Atomic_Bomb</a>
Beijinger11 hours ago
"As the German scientists were racing against time,"The Germans tried to build a reactor, not a bomb, or am I wrong?
- beloch9 hours ago
 Building a reactor was a step on the way to building a bomb.Two isotopes were used for fission bombs in WWII: Uranium 235 and Plutonium. More than 99% of naturally occurring Uranium is Uranium 238, which will not sustain a chain reaction necessary for a bomb. There are only trace amounts of Plutonium in nature, but it can be produced in reactors that use U238 for fuel. So, to make a fission bomb you need to either separate U235 from U238 or build a reactor to create Plutonium.It's worth noting that the shortage of heavy water was no accident. The Allies sabotaged the heavy water production facility in Norway that Germany relied on[1].________________________[1]<a href="https://en.wikipedia.org/wiki/Norwegian_heavy_water_sabotage" rel="nofollow">https://en.wikipedia.org/wiki/Norwegian_heavy_water_sabotage</a>
 - hunterpayne7 hours ago
 Nitpick. You can't power a reactor with U-238. You breed U-238 into Pu-239 and that can power a reactor.
 - alcover3 hours ago
 RBMK used only 2% enriched though.
 - jojobas5 hours ago
 It was the first step out of 1000 to make. It took both US and USSR more than 2 years from a working reactor to a working bomb, all away from bombing raids. Reactors used to make bomb plutonium were a lot larger and more powerful than these first research ones, and Germany was nowhere near the required scale.Germans also didn't have anything resembling a workable bomb design.
- rjsw10 hours ago
 The US built a reactor first too [1], followed by others [2] as part of the Manhattan Project.[1] <a href="https://en.wikipedia.org/wiki/Chicago_Pile-1" rel="nofollow">https://en.wikipedia.org/wiki/Chicago_Pile-1</a> [2] <a href="https://en.wikipedia.org/wiki/Hanford_Site" rel="nofollow">https://en.wikipedia.org/wiki/Hanford_Site</a>
 - defrost10 hours ago
 In the context of the time, those US scientists that built a reactor were all in for nuclear energy and absolutely 100% did not think that a nuclear weapon was economically feasible."Economically feasible" meaning maybe, perhaps, theoretically possible but even if so astronomically expensive in time, money, and physical resources.It took the UK/CA/AU Tube Alloys group to find ways to make a weapon more practical, and multiple letters, attempts, and a one on one press the flesh tour to convince the US nuclear types that a weapon was both possible and achievable.
 - bluGill10 hours ago
 If you go to the Los Alamos Science Museum you can see an original letter from Albert Einstein where he proposed that a nuclear bomb could be fit on a ship and sailed into harbor in 1938. A ship-sized nuclear bomb was not of interest to President Roosevelt at the time for a likely good reason. It's only when the UK realized that it wasn't a ship size. It was something that you could drop from a conventional airplane bomber of the day that the US became interested.
 - defrost10 hours ago
 Seen it, read it, and aware of why it was ignored at the time - the ability to make such a weapon, as relayed by Einstein, was a hearsay tale of speculation.Some time later Mark Oliphant visited the US in person and walked key people through a circles and arrows on chalkboard breakdown of how such a thing would be actually possible.
 - lazide10 hours ago
 It was also a failure of imagination. A ship sized tsar bomba at the time would still be quite interesting - armor the ship like a Iowa class (or more), and give it an automated navigator (very doable at the time, plus or minus a mile or two), and it’s a war ender.
 gonzalohm10 hours ago
 And sail the ship into Berlin?
 lazide9 hours ago
 Wait until the wind is right, add some of the right contaminants, and you wouldn’t need to do so to poison all of Germany for at least a generation.Also, Tokyo Bay.For the Axis powers, it would be an even easier sell of course.At least if any of them could believe - or even imagine - that it actually could exist or be as devastating as it was of course. And frankly, unless you saw the footage of an actual Tsar Bomba, how could anyone?
 defrost9 hours ago
 Footage of the actual Tsar Bomba has no scale, detonating as it did high up in the atmosphere - for anyone watching it might have been a really big or really small explosion.For the first bomb ever made to immediately jump to Tsar Bomba size, or for it to utilise an understanding of fallout and contaminants that didn't exist prior to the Castle Bravo tests seems ... unlikely.
 - chasil10 hours ago
 The plutonium bomb was vastly more difficult to design than the uranium version.Were both judged infeasible for different reasons? Perhaps uranium purification challenges and the implosion required for plutonium?
 - defrost10 hours ago
 In general the take was that human created nuclear weapons were infeasible (regardless of design) because of what was thought to be the barrier to cross to achieve a chain reaction.The Frisch–Peierls memorandum changed that understanding ... provided that reading of the FP-memorandum was convincingly conveyed to people that made things happen, what Einstein put to paper (and was ignored) and that Oliphant pushed through in person.Little Boy on Hiroshima was a gun design, a grossly inefficient McGyver that used some 64 kilograms of enriched uranium to successfully convert less than half a gram to energy.Fat Man on Nagasaki was an implosion device - a necessary design change due to simply not having enough uranium or an enrichment pipeline to sustain the needs of a gun design.The first device detonated, at Trinity in the USofA, was an implosion device, created to test the more difficult design.Further, there was an abandoned / discarded "Thin Man" device IIRC.These were all alternative implementations that were pursued after the FP-memorandum was pushed about to make the case that weapons were apparently possible rather than not yet achievable - the prevailing belief in the US prior to Oliphant doing the rounds.
 rjsw9 hours ago
 Trinity and Fat Man were plutonium bombs, they needed to be implosion designs because it was realized that a gun wouldn't work using plutonium [1].[1] <a href="https://en.wikipedia.org/wiki/Thin_Man_(nuclear_bomb)" rel="nofollow">https://en.wikipedia.org/wiki/Thin_Man_(nuclear_bomb)</a>
 defrost9 hours ago
 As I said above - and perhaps you might like to try a primary source rather than wikipedia ?<pre><code> These weapons were, however, as different as their monikers imply. Little Boy was a uranium, gun-type weapon, whereas Fat Man was a plutonium, implosion-style weapon. Two types were needed because there was only enough uranium for one gun-type weapon, and the U.S. government knew it would need to make more than one weapon. </code></pre> ~ Los Alamos Nuclear Lab <a href="https://www.lanl.gov/media/publications/the-vault/1023-a-tale-of-two-bomb-designs" rel="nofollow">https://www.lanl.gov/media/publications/the-vault/1023-a-tal...</a>
AndrewKemendo13 hours ago
Awesome article and interesting to see Heisenberg get it wrong. It really was a perfect situation for the US because we could get all the radioactive material with little issue.A clean reminder that logistics is everything.Also cool that the author is married to Sean Carroll.
- failbuffer11 hours ago
 It mega-helped that Edgar Sengier saw the importance of uranium ore and shipped 1200 tons of it out of the Congo to New York before the U.S. government even realized it would need it.
- 1970-01-0111 hours ago
 We always knew they weren't close because Moe Berg was going to shoot Heisenberg during his lectures in Zurich if he suspected they were.
mmooss13 hours ago
Relatively recently, recordings were released of conversations between captured Nazi scientists held at a house in the UK (I think I saw it on HN). They were housed together and the house was bugged purposely to capture casual conversation for intelligence purposes.IIRC one conclusion they/some of the scientists drew was that the culture of the Nazi regime - the paranoia, fear, and violence - made a project on that scale impossible. Enough talented, high-ego people could not work together on project that large and demanding.Also, IIRC, when the Hiroshima bomb was announced, many couldn't believe it. They had been working on a power generation reactor as a first step - though I'm not sure the OP fits that story?Also, maybe Heisenberg didn't want to succeed? Has that ever been resolved to some degree?
- Steve442 hours ago
 The transcripts from that bugged house were turned into a play, we saw it in Richmond, London, a few years ago. It was really well done and seemed to by enjoyed by everyone, not just those interested in the science & its history.<a href="https://www.whatsonstage.com/shows/outer-london-theatre/farm-hall_614030719/" rel="nofollow">https://www.whatsonstage.com/shows/outer-london-theatre/farm...</a>
- ZnerflBerp12 hours ago
 The sheer economic costs of the manhattan project were prohibitive to a nation like Germany, even if they'd managed to build a functional project team.(how many nations had 14,700 tons of silver lying around)
 - fooker11 hours ago
 A nation like Germany on the cusp of losing a war sure. The opposite scenario of Germany controlling all the resources of Europe and Africa is a scary proposition.
 - jcranmer11 hours ago
 > The opposite scenario of Germany controlling all the resources of Europe and Africa is a scary proposition.It shouldn't be. In WW2, in 1942, Germany did essentially control all of Europe, save only the UK. And at the height of its power, Germany's vast industrial machine produced roughly on par with the UK. Not the entire British Empire, just UK.It turns out that the Nazis were complete incompetent buffoons when it came to economic management. Their grand master plan for Europe was to overrun the east, not for some vast rich treasure trove of minerals to fuel an industrial juggernaut, but to plop down more homesteads to feed their inefficient agricultural economy. And even if the Nazis had a grand plan to become an industrial juggernaut, they still faced the prospect of the industrial juggernaut par excellence, the US.
 - lazide10 hours ago
 The US at the start of WW2 was primarily an inefficient agrarian economy.The war machine is what changed that - that and not being reachable by enemy bombers, and hence not bombed to bits.Germany started middling and ended destroyed.
 jcranmer8 hours ago
 No, that's categorically not true!Germany required like 10 percentage points more of its labor force in agriculture in 1939 than the US did, and that still wasn't enough to make Germany self-sufficient in food; the US was of course one of the major food exporters in the world (in neither case were agriculture workers more than a third of the population, I should note). US agriculture also had largely mechanized in the 1910s, albeit many farms did switch back to draft animals during the 1920s and 1930s due to the collapse in agricultural prices, making animal feed grown on your own farm cheaper than buying fuel for the tractor. Europe agriculture largely didn't mechanize until the 1950s, after WW2.
 lazide5 hours ago
 [<a href="https://en.wikipedia.org/wiki/Recession_of_1937%E2%80%931938" rel="nofollow">https://en.wikipedia.org/wiki/Recession_of_1937%E2%80%931938</a>]
 hunterpayne7 hours ago
 Complete nonsense. The US became the largest economy in 1870 (70 years before the start of the war). And in 1875 it became the 1st country to start using crude oil. Even in 1940, the US exported 75% of the worlds oil. Most of the main directions of advance by Germany and Japan were trying to get access to the 15% of the worlds oil they could get to (Romania, Baku and Indonesia). The US economy was 3x the size of Germany's (#2 by GDP) and was the majority of the world's industrial and manufacturing.Let's try this another way, during WWII the US built warship tonnage equivalent to all the rest of the world's navies combined...in just 1943. Then the US did that again in 1944. At one point, the US hit a Japanese fleet with 17 fleet carriers at once. Keep in mind the Japanese only built 9 fleet carriers total and that was considered the most powerful fleet in the world at the beginning of the war.
 Lum23 hours ago
 « Most of the main directions of advance by Germany and Japan were trying to get access to the 15% of the worlds oil they could get to (Romania, Baku and Indonesia). »This is the key to understand WW2. The oil, and the iron ore (Sweden, hence Norway). But mostly the oil. All the rest about ideology etc in Western/Anglo historiography is distraction at best (but actually rather deliberately misleading). Like "Hitler sought world domination" and similar junk, this is just ludicrous, we can simply take a look at the map and take note of who had already secured world domination.The lack of oil had already been painful for Germany during Britain's first "World War", having to rely on horses to a much larger extent than the enemy, and the importance of oil had only risen with motorization.
 lazide5 hours ago
 not even close [<a href="https://www.statista.com/statistics/1076289/gdp-continent-1820-1870-1913/" rel="nofollow">https://www.statista.com/statistics/1076289/gdp-continent-18...</a>]]telling that your example of actual concrete economic output was many years into the war, eh?
 - dboreham11 hours ago
 I don't believe the silver was strictly necessary. Copper windings would have worked for the calutron. Silver was used because copper was not as easily available at the time. But the point is valid. The project was originally British, moved to the US for economic reasons.
 - throwaway8152312 hours ago
 The silver bus bars in the magnetic separators were kind of a stunt, if that's what you're thinking of.
- jcranmer12 hours ago
 > Also, maybe Heisenberg didn't want to succeed? Has that ever been resolved to some degree?From the Farm Hall transcripts, it seems that Heisenberg was "happy" to have been working on a reactor and not a bomb, but from context, this seems less like an objection to the principle of working on a weapon and more like gratitude that the Allies couldn't hang him for working on an atomic bomb. Recall that the conversations took place after Germany had been utterly defeated and the scientists were prisoners at the mercy of the British--prisoners in a gilded cage, but prisoners nonetheless.
- kragen12 hours ago
 > one conclusion they/some of the scientists drew was that the culture of the Nazi regime - the paranoia, fear, and violence - made a project on that scale impossibleThis makes me think about the pervasive classification and paranoia in the "defense" contractors supporting the US Department of "Defense". Any information that's classified, even at the lowest "confidential" level, is only provided on a "need-to-know" basis. And unclassified projects are sort of looked down on, so there's a perverse incentive to classify more than necessary. This "secretive, isolationist approach" seems like it probably prevents a lot of groups from "sharing information or resources", in the article's words (though it concludes that wasn't the biggest problem facing the German effort).When sharing classified information that someone might not need to know might be a crime, and might get your clearance pulled even if it's not, the incentives run strongly counter to sharing information. Consequently, I confidently claim that there are very, very few people in a position to serendipitously make significant discoveries that involve combining two or three different classified facts.(I don't actually know this, because I don't know any classified facts.)Maybe this is part of the sclerosis that causes the US defense-industrial complex to "basically produce useless junk", in the words of Les Earnest (<a href="https://www.youtube.com/watch?v=Ych6pvLMKCU" rel="nofollow">https://www.youtube.com/watch?v=Ych6pvLMKCU</a>), and which prompts Sergey Tovkach to say, "There isn’t a single Western drone that’s proven itself effective in this conflict." (<a href="https://www.youtube.com/watch?v=RmfNUM2CbbM" rel="nofollow">https://www.youtube.com/watch?v=RmfNUM2CbbM</a>). Maybe that's why Russian propaganda in 02024 reported that Ukraine had to withdraw the USA-made M1A1 tanks far from the front (<a href="https://www.youtube.com/watch?v=aCIN-t3VxJ0" rel="nofollow">https://www.youtube.com/watch?v=aCIN-t3VxJ0</a>).
 - mmooss9 hours ago
 Not to take away from your comment, but to clarify: That's not the paranoia the Nazi scientists meant. They meant fear of the SS, being spied on, being stabbed in the back by a co-worker in a power struggle, fear for the families, etc.
 - kragen7 hours ago
 I'm sorry, I didn't mean to imply that the paranoia was similar in the two cases. I appreciate the clarification.
 - brians11 hours ago
 Or look at it the other way: having seen what assembled scientists can do, we separated them, gave them an Orwellian environment, and slept easy.See Anathem for more on this.
 - insom10 hours ago
 A double Stephenson comments section :)
codedokode8 hours ago
Why famous scientists supported Nazi regime? Aren't scientists supposed to be smart?
- Aachen2 minutes ago
 Without agreeing with the stereotype that scientists are supposed to be smart¹, yeah this is something that worries me. Be it naziism, slavery, racism the way that it was considered normal and legal when my grandparents were alive: there are so many things about which I wonder how large groups (not just a few individuals that aren't right in the head) can be convinced to believe it.How do I know what I'm doing in life is right? By what mechanism could I ensure that I believe someone who tells me that Jews aren't the cause of all evil if I lived in ~1940 Germany? What makes people increasingly vote for racist parties since covid? The average person hasn't gotten any smarter or dumber in many thousands of years; evolution is not that fast. At best, genes might be expressed differently based on environmental factors, but I'm not aware that this is a factor for the aforementioned inhumane beliefs¹ we can all do amazing things when we have the right idea in the right situation with the means to execute it. Of course, good ideas occur to a smarter person more frequently, and they might be inclined to become scientists because it's an environment seemingly meant for working on new ideas, but that doesn't mean everyone there is per se smart. Lots of people are only topically smart (not to be confused with topical knowledge: I scored both top % and bottom % depending on which part of the iq test you looked at, so that's not about knowledge but about abilities. Many people think I'm smart, but I think they mainly notice the parts where I'm unusually good rather than the 'boring' parts where I perform somewhat below average, or they attribute it to laziness)
- kakacik3 hours ago
 Smart people still work for trump regime. Lets put it this way - it won't be viewed kindly by history neither. Yet it keeps happening, people have various priorities and high intelligence doesn't guarantee high morals. musk keeps doing nazi gestures and behavior and clearly his values are not far neither, yet he is supposedly smart and definitely doesn't have to behave that way, its a personal choice.Also, a lot of people are trivial to manipulate and have emotional weaknesses that are easy to abuse by skilled manipulators, smart or not.
 - 2b3a5149 minutes ago
 <a href="https://en.wikipedia.org/wiki/Ettore_Majorana" rel="nofollow">https://en.wikipedia.org/wiki/Ettore_Majorana</a>Majorana basically disappeared in 1938. It has been suggested that he could see the feasibility of weapons using fission (Leonardo Sciascia wrote a play about this). Opinions vary and the issue is cloudy and ripe for fiction.
- russdill6 hours ago
 The Vintage Space has an excellent video that does talk a fair bit about individually scientists feelings toward the Nazi regime<a href="https://www.youtube.com/watch?v=FGvS4T-r_fk" rel="nofollow">https://www.youtube.com/watch?v=FGvS4T-r_fk</a>