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.

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

[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.

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.