{"id":7220,"date":"2018-06-30T19:21:11","date_gmt":"2018-06-30T17:21:11","guid":{"rendered":"http:\/\/www.randform.org\/blog\/?p=7220"},"modified":"2018-06-30T20:00:39","modified_gmt":"2018-06-30T18:00:39","slug":"work-to-rule","status":"publish","type":"post","link":"https:\/\/www.randform.org\/blog\/?p=7220","title":{"rendered":"Work-to-rule?"},"content":{"rendered":"

Last year (Jan 2017) there was a long essay in the german newspaper “Die Zeit” (“The time”) about how important a natural scientific evaluation could be for historical research. The essay: “Darum hatte Hitler keine Atombombe” (“That’s why Hitler had no nuclear bomb”)<\/a> was written by physicist Manfred Popp<\/a>. A very brief summary of his argumentation is that a lot of historical research about german nuclear research during Nazi times was more or less flawed due to missing knowledge or misinterpretations of physical facts. <\/p>\n


\n<\/p>\n

One of his main examples was that most historians seemed to had overseen that the nuclear physicists in Germany, during that time, weren’t apparently aware of the fact that the physics of a nuclear reactor and that of a nuclear bomb is rather fundamentally different. In particular Uranium 235 in a reactor needs “slow” neutrons, i.e. the neutrons are “moderated”. For a nuclear bomb however – as Popp explains, -the neutrons should not be moderated – they need to be “fast” . This is apparently mostly due to thermodynamic considerations (i.e. “the heat”) . <\/p>\n

In his essay Popp proposes a couple of facts which undermine his assertion. So for example historian Mark Walker<\/a> found a sentence in a 1942 report, which was put together to document the research results of the Uranverein,<\/a> which said that “F\u00fcr eine Explosion m\u00fcsse man 10 bis 100 Kilogramm Uran-235 oder Element 94 an einem Ort vereinigen.” (“For an explosion one needs to put together 10 to 100 kilogram of Uran 235 or Element 94 at one location”). That was about exactly the same estimation which was made in the US at that time; however if one looks into the technical part of the report than one sees that the bomb was only mentioned as a special case of reactor physics and in the processes discussed there, nothing was said about fast neutrons. The report was by the way for a conference in which the further funding of the research was at stake. <\/p>\n

Likewise P. M\u00fcller, one of Werner Heisenbergs Ph.D. students, had rightly calculated the amount of enrichment, which is necessary for a nuclear explosion, namely 70 %, he however also found that one should be strongly in need for a moderator, but as Popp writes “Ein Moderator ist Gift f\u00fcr die Bombe” (“A moderator is poison for the bomb”). Furthermore Popp acknowledges that it is true that Werner Heisenberg showed in Februar 1942 a scheme of the fission principles in natural and pure uranium 235 without a moderator, but that again there is no explicit mention of fast neutrons.
\nIn addition in the famous Farm-Hall protocolls<\/a> Heisenberg was unable to conduct the simplest calculations without mistakes. It took Heisenberg however only a week to catch up. Popp asserts:<\/p>\n

Den Mitgliedern des Uranvereins war die Funktionsweise einer nuklearen Explosion fremd. Heisenbergs Anf\u00e4ngerfehler belegen, dass er sie noch nie durchgerechnet hatte. Sein Seminarvortrag wiederum zeigt, dass ihm eine Woche gen\u00fcgte, um ein Grundverst\u00e4ndnis der Physik der Bombe zu erlangen.<\/p><\/blockquote>\n

translation:<\/p>\n

Members of the Uranverein were not really aquainted with the modes of operation of a nuclear explosion. Heisenberg’s beginners mistakes show that he had never calculated it. His seminar talk however shows that one week was enough for him to get a principle understanding of the physics of the bomb.<\/p><\/blockquote>\n

So Popp concludes that it is rather not the case that the nuclear physicists in Germany were in principle too incompetent to construct a nuclear bomb, as some historians concluded, neither were they the good angels that refused to cooperate with the Nazi regime, but it is rather likely that the scientist deliberately didn’t really spend a big effort on actually constructing a bomb (in particular Heisenberg who apparently didn’t even spend a week on thinking about a bomb). Popp also explains that a rather clear reason for this was probably that it was the soundest thing to do. That is doing research for a nuclear reactor, with which one could in principle enable bomb construction (In particular Heisenbergs collaborator Weiz\u00e4cker<\/a> had a 1941 patent on plutonium production) was on one hand important enough to avoid the front, on the other hand it appeared not promising enough to get the Nazi’s big attention:<\/p>\n

In dieser Zeit muss Heisenberg klar geworden sein: Man konnte diesem totalit\u00e4ren Regime nur verschweigen, was man nicht wusste. Dass er nie herausgefunden hatte, wie die Bombe funktioniert, war nicht Unf\u00e4higkeit, sondern Klugheit. <\/p><\/blockquote>\n

translation:<\/p>\n

In this time it must have become clear to Heisenberg: With such a totalitarian regime at hand it was only possible to keep silent, if you didn’t know. That he never found out how the bomb worked was not incapability but sagacity.<\/p><\/blockquote>\n

In fact Heisenberg wrote in “Quantentheorie und Philosphie” (Reclam 1979 p. 89 “\u00dcber die Verantwortung des Forschers”)<\/p>\n

\n“Nat\u00fcrlich wird man nicht annehmen k\u00f6nnen, dass die Physiker und Techniker wichtige politische Entscheidungen besser f\u00e4llen k\u00f6nnten als die Politiker. Aber sie haben in ihrer wissenschaftlichen Arbeit besser gelernt, objektiv, sachlich und, was das wichtigste ist in gro\u00dfen Zusammenh\u00e4ngen zu denken. ….Wenn man so denkt, k\u00f6nnte man allerdings den amerikanischen Atomphysikern den Vorwurf nicht ersparen, dass sie sich nicht genug um politischen Einfluss bem\u00fcht, dass sie die Entscheidung \u00fcber die Verwendung der Atombombe zu fr\u00fch aus der Hand gegeben haben. Ich weiss nicht, ob wir in diesem Zusammenhang das Wort “Vorwurf” \u00fcberhaupt in den Mund nehmen d\u00fcrfen. Wahrscheinlich haben wir an dieser Stelle einfach mehr Gl\u00fcck gehabt als unsere Freunde auf der anderen Seite des Ozeans.”\n<\/p><\/blockquote>\n

translation<\/p>\n

Of course one can not assume that physicists and technicians can do better decisions than politicians. But in their scientific work they have better learnt to think objectively, matter-of-fact, and most importantly to think in bigger contexts. … If one thinks like this one however can’t spare the american nuclear physicists of the reproach that they didn’t care enough to obtain political influence, that they gave the decision about the nuclear bomb’s deployment too early out of their hands. I don’t know though if we are at all allowed to say the word “reproach” in such a context. Probably we were just luckier than our friends on the other side of the ocean.\n<\/p><\/blockquote>\n

There is of course more to say here. Like about the problematic meeting of Heisenberg with Niels Bohr<\/a> in September 1941 in Kopenhagen, where – according to Heisenberg – he didn’t dare to speak openly and thus was misunderstood by Niels Bohr<\/a>.<\/p>\n

Morover Heisenberg and his direct collaborators were certainly the most important but not the only “players” in Nazi nuclear physics research. In fact the research landscape was quite splintered<\/a> and in partially quite in competition with each other, it even included more or less “private research projects” like the one in Zeuthen, which was mostly financed by the Nazi postminister Wilhelm Ohnesorge.<\/a> <\/p>\n

It should also be said that due to his special position in the nuclear physics research landscape and due to war times Heisenberg didn’t have too much time in general and in particular not for doing much research, like in a letter to his wife<\/a> he writes in June 1942:<\/p>\n

\nJetzt sitz ich allein in der grossen Stube oben u. lasse die Ereignisse des Tages mir nochmal durch den Kopf gehen. Wann dieses dauernde Leben bis an den Rand der Kr\u00e4fte wohl sich wieder zum Besseren wendet? Ich denke, im Winter werden wir
\nmehr dar\u00fcber wissen.<\/p><\/blockquote>\n

Now I sit in the big living room upstairs and think about the events of this day. When will this life at the end of one’s tether get better? I think in winter we will know more.<\/p><\/blockquote>\n

He was right: the battle of Stalingrad in winter 1942\/43<\/a> was a turning point in WWII. It was the first time that the Nazi’s acknowledged a failure in war effort. But as Wikipedia writes it was also when “Minister of Propaganda Joseph Goebbels gave the famous Sportpalast speech in Berlin, encouraging the Germans to accept a total war that would claim all resources and efforts from the entire population.” <\/p>\n","protected":false},"excerpt":{"rendered":"

Last year (Jan 2017) there was a long essay in the german newspaper “Die Zeit” (“The time”) about how important a natural scientific evaluation could be for historical research. The essay: “Darum hatte Hitler keine Atombombe” (“That’s why Hitler had no nuclear bomb”) was written by physicist Manfred Popp. A very brief summary of his […]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[13,15,33,2,34,8,7,19],"tags":[],"_links":{"self":[{"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=\/wp\/v2\/posts\/7220"}],"collection":[{"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=7220"}],"version-history":[{"count":12,"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=\/wp\/v2\/posts\/7220\/revisions"}],"predecessor-version":[{"id":7232,"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=\/wp\/v2\/posts\/7220\/revisions\/7232"}],"wp:attachment":[{"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7220"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7220"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7220"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}