Followup To Bohr-Heisenberg Meeting

December writes "As a follow up to this slashdot article, "The family of Niels Bohr has decided to release all documents deposited at the Niels Bohr Archive, either written or dictated by Niels Bohr, pertaining specifically to the meeting between Bohr and Heisenberg in September 1941. There are in all eleven documents. The decision has been made in order to avoid possible misunderstandings regarding the contents of the documents." See the Niels Bohr Archive at http://www.nba.nbi.dk/"

Comments

Nothing new?

[/ASCII]

Checked out the documents. These are documents written in the sixties, i.e. twenty years after Heissenberg supposedly tried to convince Bohr to build a german A-bomb. Doesn't really add anything interesting to the story. Bohr had his version, Heissenberg his. Neither one can back it up.

Why is this such a big deal anyway? Heissenberg, one of many famous modern physisists might have been a Nazi. So was almost the entire german population for crying out loud. Most of them did not know the entire story, and later on most of them understood that they had been horribly wrong. Let it rest.

Re:Nothing new?

[Rob.Mathers]

I think many Germans who were living in Germany in the 30s and 40s would balk at the statement that "almost the entire german population" were Nazis. There were very large numbers of them that opposed Hitler and Nazism, either privately or publicly (those who did so publicly were not around much longer however). Just because the leader of a country is something, do not assume that all, most, or even some of the citizens agree with his beliefs. As someone who has had to suffer life under an oppressive regime will tell you, you generally don't have much choice in the matter.

Re:Nothing new?

[jedidiah]

Also, it's quite likely that "member of Nazi party" in Nazi Germany is much the same as "member of communist party" in the Soviet Union. In both instances it was simply wise in terms of your continued survival to make pretenses about supporting the current regime. Even today in the USA there are elements of orthodoxy that one is better off appearing to support.

Failing to be of extraordinary moral courage does not make one evil. It makes one average.

People need to get a grip and realize that Titans of physics were mere mortals in any other area of human endeavor.

Schroedinger?

[Anonymous Coward]

I wonder if he knew Schroedinger? That way, Germany could say it had a nuclear weapons programme, maybe in a box, possibly with a cat (alive or dead), but no one would know without looking.

If they knew Seuss, it'd be the Cat in the Hat in the Box - with the Nazi weapons programme... I'm not sure where the eggs and ham fit in though, can anyone clarify?

I've had waay too much coffee...

Evidently...

[pyrrho]

Bohr thought the sun would continue to rise in the east. Heinsenberg was said to be uncertain.

Just saw it on TV

[Jacco de Leeuw]

I haven't read the letters but there was a program on TV this evening. IANAH but I'm just writing what I heard on that show.

Basically, they said that Heisenberg travelled to his friend Bohr whom he hadn't seen for years. This was in 1941 while the Germans were still going strong. Bohr didn't believe an atomic bomb was possible. Heisenberg was furious that Bohr didn't believe his physics and replied that he had been heading a team for two years. Heisenberg wanted Bohr on the team. Germany will win; be a slave or be a Nazi.

We now know the outcome. Bohr fled to Sweden, and Heisenberg didn't make the bomb. The thing with these letters is that until now people thought Heisenberg deliberately frustrated the German war effort. Which is apparently not the case.

Re:Just saw it on TV

[thesupraman]

One very important fact to remember is that the Russians (and Germans) around this time were using an incorrect estimate of the cross section of uranium, which did seem to indicate that sustained fission was not possible. The Americans managed to get a different (and later proven more accurate) measurement, which showed that a chain reaction was possible, this is one of the major reasons the Russians ended up so far behind at first in the atomic race.

The Germans and Russians certainly had a large initial lead in the more theoretical aspects of radiation and atomic physics, however this one incorrect measurement certainly threw the Russians so far off the track that it basically stopped their work in the area for quite a few years.

The Americans for a long time refused to believe how far behind the Russians were, and managed to loose much advantage by following politically 'suitable' beliefs rather than believing their own intelligence information, whcih turned out to be quite accurate with respect to the Russian position.

On the flip side, both of these men were great scientists, I personally feel it is immaterial whos 'side' they were on in a war.

Re:Just saw it on TV

[Nick_Gunz]

Ok, I am a historian, or rather a history student, and I've studied this problem in passing while doing a short paper on the ALSOS mission.

Disclaimer: this was some time ago, and my recollections are hazy. Plus, I'm speaking loosely here, so this isn't my considered historical opinion, just my offhand thoughts as a semi-informed person. Oh, and I don't have any of the books and documents here to refer to, so I may make factual errors. - I think that about covers it

1. I realise you're just repeating what you saw on TV, but I think that either the TV program really twisted the history hard, or you didn't quite understand it correctly. I don't think anybody's actually seriously suggested that H tried to recruit B for the German A-bomb program.
H said that he informed B of the German program in order to get his agreement that all scientists everywhere should refrain from building a bomb (knowing, of course, that B had contacts in Britain and the United States).
B said that H informed him of the German program for... well, he never quite explained it. From what he said after the war, he was just really shocked by the revelation that H was working on the program and was very upset by the idea that his friend might be working against the common interest of humanity.

2. I've read through the letters and they *don't* substantially clear up the case. Perhaps more documents to be released will tell us more, but these documents simply give us a lucid and interesting account of B's outrage. He says things like , but he doesn't specifically tell us *what those words were*. Not having read B's documents myself, I can't tell you whether he meant things like this seriously, or whether it was just a figure of speech, nor do I know how accurate his memory would have been. What we do know is that his impressions of that day were coloured deeply by his dismay at H's pro-Nazi comments prior to the private meeting between H and B. Which brings us to...

3. It is unclear as to how deeply H supported the Nazi regime, if at all. Now I am not an H biographer, and I would like to refer you to the many fascinating books written about him for actual authoritative comment. Having said that, a Coles Notes version is that H's relationship with Nazism and with German nationalism was extremely complex and ambiguous (for any historians out there, I discuss this merely because I'm sick to death of hackers telling me "just go program it yourself" and I think that telling them "just go read a bunch of history books yourself" would be just as bad). I would say that most observers believe that H saw himself as a patriotic and loyal German, but not a supporter of the Nazis per se. There were many Germans, at the time, who believed that the Nazis were, rightly or wrongly, the official government of Germany and that to go against them would be an act of treason against Germany (just to make it clear: I believe, personally, that this attitude was wrong, wrong, wrong, and that the Nazis were bad, bad, bad. ok? so nobody make like I'm defending this or anything). H seems to have held this opinion, at least in the period before the war (but more on that later).
Now it actually gets way more complicated than this because, I am told, in German culture there were different concepts for treason against the nation and treason against the government, but that doesn't change the fact that we *have* to keep this idea in mind (keep in mind that I'm not an expert on German culture in the middle of the 20th century). Many Germans, having courageously resisted the Nazis, had to face the stigma of having "betrayed their country" during the war.
If you want to read a fascinating and very readable account of the way these ambiguities played out among the German atomic scientists, there is a book called _Hitler's Uranium Club: The Secret Recordings at Farm Hall_ edited by Jeremy Bernstein.

This is where the plot thickens because, if we actually look at the historical record, there *was no* Nazi atomic bomb program. "What?" you say "no a-bomb program? Then what are we arguing about?"
It turns out, and bare with me here, because I don't remember the chronology, that the Nazis got wind of the idea of an a-bomb, and called in a bunch of atomic scientists to ask them about it. The answer they got was, you guessed it, ambiguous. They were told that, yes, it would be possible to build a bomb and, yes, it would be powerful and reasonably small. However, the scientists also hinted that such a program would consume an inordinate amount of resources, might not work. Now that was a reasonable thing to say, and doesn't necessarily cast doubt on their commitment to helping the war effort. But what comes next rings alarm bells: when asked whether they could guarantee that the chain reaction in a fission explosion would be contained - that is to say, to guarantee that it would not start a chain reaction in the rest of the matter in the world and turn the entire planet into one great nuclear fission fireball - they said that they could not. Now anybody who knows a little nuclear physics knows that this was a preposterous statement. Why would a nuclear explosion magically turn the air into fissionable material? You need constant core-of-the-sun like temperatures to do that. The best explanation is that the German scientists had *very* cold feet about running a bomb program.
Incidentally, this was not necessarily because they feared arming Hitler with an a-bomb. There were other good reasons for them to not want to run an a-bomb program I won't go into here for lack of space and time (rimshot!).
In the end, the scientists got to have their cake and eat it to. Substantial amounts of government money were put into a *reactor* program, allowing them to say in a job and keep their students away from the Eastern Front. At the same time, they weren't burdened with the huge and risky job of trying to produce an atomic bomb for the state.

So I said I'd get back to why H might have changed his views during the war... Several writers have pointed out, I think rightly, that H was "betraying" the German war effort by telling B about the possibility that the Germans might develop an a-bomb at all. H *knew* that B had contacts outside Nazi-occupied Europe. H *knew* that B was an ardent anti-Nazi. He was an intelligent man. He could not have been blind to the fact that B would certainly repeat every word he said to his contacts in Sweden and thence to Britain. So however we interpret the meeting, I cannot see a way in which it would support the idea that H was an ardent Nazi trying to strengthen the Nazi cause. It just doesn't make sense.

But that's the trouble, you see. None of it makes perfect sense. Nobody will ever know precisely what happened in that meeting or why, but if I had to guess, I would say that H was conflicted about what to do. He was mixed up. On the one hand lay, what her perceived to be, his duty to the state and his genuine patriotism. On the other hand lay his fear of the destructive power of the bomb in anybody's hands. Probably, on a third hand, lay his duty to science, and then on a fourth hand his friend and so on and so on (and yes, I'm aware of the fact that I totally mangled that metaphor).

Anyway, I apologise for how long that was, but I hope it helps clear up a few things.

Still implausible

[Anonymous Coward]

To separate, process, and manufacture the uranium and plutonium necessary for the A bombs, it required 32% of the US electrical output, 23% of the US Silver output (144,000 Troy Ounces was the figure I believe), and 14% of the US aluminum output to construct the plants (at Oak Ridge, Tennessee and Hartford, Washington). Remember this is 1944 people - height of America's industrial might. Now ask yourself if Germany could've done the same...

An interesting Heisenberg quote

[SIGBUS]

In October 1943, in a letter to Dutch scientist B. G. Casimir, Heisenberg wrote:

History legitimizes Germany to rule Europe and later the world. Only a nation that rules ruthlessly can maintain itself. Democracy cannot develop sufficient energy to rule Europe. There are, therefore, only two possibilities: Germany and Russia, and perhaps a Europe under German leadership is the lesser evil. [1]

In 1942, a prototype reactor in Leipzig exploded when heavy water leaked into a uranium shell, shortly before it would have reached criticality. [2]

We're DAMN LUCKY that Heisenberg's efforts ultimately failed.

[1] Blood and Water: Sabotaging Hitler's Bomb (ISBN 0-8050-3206-1), by Dan Kurzman, p.35.
[2] Ibid, p. 38.

It's irrelevant

[chazR]

Fact #1: Bohr and Heisenberg were there when quantum physics was being born. Both contributed greatly to it's discovery.

Fact #2: The Nazis never had the ability to fight and build a nuke after the astonishing raid against the heavy water plant in Norway. In 1941, they had lost the Battle of Britain, were losing the capability to launch an invasion of Britain, and were focussing a lot of effort on the Battle of the Atlantic.

<interlude >
(which they would have won until American long-range bombers(B29s) became available in large numbers - The courage and acheivements of the British Royal and Merchant navies should not be forgotten, but it was the closing of the Iceland-UK gap by airpower that won the Battle of the Atlantic. Thankyou once again America.)
</interlude >

It's all ancient history. But please give respect to the British-trained Norwegians who perpetrated the astonishing raid that ended Nazi nuclear capabilities.

More information:here
Basically, they landed by parachute in Norway, infiltrated one of the most highly defended places in Nazi-controlled Europe, and set of some charges. The charges were placed next to some fat cables deep in a long tunnel. The cables were carrying enough current (many tens of thousands of amps) that the electromagnetic effects when they shorted blew a kilometer of tunnel to bits.

Another team sank a ship carrying 1000 tons of heavy water from Norway to Germany.

After those losses, the German nuke program didn't have chance.

<googlefailure&gt>
Google (and AltaVista) have failed to give many useful hits on these events. The people who executed these raids deserve more web presence. Please post links.
</googlefailure&gt>

Why the Germans didn't get the bomb

[Therin]

If you read "Virus House", later published as "The German Atomic Bomb", you will see that the Nazis (Heisenberg, et al.) were astounded when they heard about Hiroshima and Nagasaki. They really didn't think it could be done. Was that due to Aryan superiority beliefs or due to their science, hard to say.

One story told by my history of science prof (he had interviewed Teller, Groves, Oppy, Szilard, etc.) was that Max Born was given the assignment of calculating the neutron cross section of graphite. This is useful for determining how much the neutrons coming out of a fission would be slowed, so they can hit another nucleus. For a reactor to work, they need to be slowed a little but not absorbed. Hence the need to know the cross-section.

He apparently goofed with the decimal points, and wound up "proving" that graphite would never work. Pretty surprising since they had a small reactor going in Paris shortly after the city fell, moderated by graphite.

That's why the Nazis kept trying to build heavy water plants - they thought that was the only possible reactor medium to use. But heavy water plants are fairly obvious targets, and Allied saboteurs took most of them out.

I'm not sure what people are trying to show

[markj02]

It's pretty clear that Heisenberg generally believed that his duties were to Germany. It's also pretty obvious that he didn't engage in a serious effort to build an A-bomb. That suggests that he didn't engage in some complex plot to sabotage a German A-bomb effort, he probably just didn't care enough to spend a lot of time on it.

That may seem like a mundane explanation, given what we now know about Nazi Germany and the power of nuclear bombs. But Heisenberg probably did not know the extent of Nazi atrocities and he also didn't know whether a real A-bomb would fizzle or bang.

It's tempting to see all of WWII in terms of villains and heroes. But most people were probably neither; they were just people trying to get on with their lives under difficult circumstances. Heisenberg could have been a hero or a villain, but he ended up being neither.

Ask a living witness...

[nairolF]

What most people don't seem to know is that Heisenberg didn't visit Bohr alone. Carl Friedrich von Weizsäcker was also there, and he is still alive today.

He gave an interview with the Süddeutsche Zeitung one or two days ago. His recollection of the meeting is rather interesting (the interview is in German, sorry).

Firstly, he says that Heisenberg started an A-bomb project in 1939, in which Weizsäcker took part, but by 1941 they came to the conclusion that they would not be able to succeed before the war was over. The problem was the tremendous effort needed to separate the isotopes. So from 1941 on they were only interested in building a reactor. Once that worked (it never did, as the heavy water production was sabotaged) there might have been the possibility to create Plutonium and build a bomb with that. But they didn't expect this to happen before the war was over by conventional means.

The reason Heisenberg went to see Bohr, according to Weizsäcker, was that they didn't want the Americans or the British to build a bomb either. If they stated publically that they're not working on a bomb, then of course nobody would have believed them. But Heisenberg thought that they might believe Bohr. So he hoped that Bohr could convince the Allies not to build the bomb either. This was not motivated by pure pacifism - he didn't want Germany to get nuked.

In 1941 the war looked pretty good for Germany, they were winning on all fronts. So basically Heisenberg believed that a German victory was inevitable, but with conventional weapons. He tried to explain this to Bohr, who was shocked. Bohr may have understood Heisenberg's "inevitable" to mean that he WAS working on a bomb, and planning to use it. But Weizsäcker suggests that Bohr may well have understood correctly, and didn't want the Germans to win (conventionally), and therefor figured that the Allies would have to build a bomb, to avoid a Nazi victory.

What we can accept as quite reliable, is the following: (a) Heisenberg did lead an A-bomb project from 1939 to 1941. (b) He came to the conclusion that he couldn't build a bomb before the war was over. (c) He continued working on a reactor from 1941 onwards (possibly with the option of producing Plutonium for later weapons use).

And what also seem quite plausible: (d) that he tried to convince Bohr that he was only working on a reactor, not a bomb. This is what he claimed afterwards, and is backed up by Weizsäcker. Many people might not believe these two, so here is another interesting piece of the puzzle:

I read some time ago, either in Physics Today or in Scientific American that when Bohr came to Los Alamos, he brought with him a sketch which Heisenberg had made during his 1941 visit. Bohr claimed it depicted a bomb which Heisenberg was building, but the people at Los Alamos recognised it as a heavy water reactor. As far as I remember, the sketch depicted a large bottle, filled with water (presumably heavy water, but only labelled "H2O"), and some stuff inside. Can anybody dig up this sketch on the net? At any rate, this strongly suggests that Bohr had misunderstood Heisenberg, and mistook Heisenberg's reactor for a bomb.