12

One of the big issues was isotope separation. Extracting uranium 235 from uranite was a huge problem that took quite an effort to overcome. In fact, just before the war started Niels Bohr believed that extracting enough uranium 235 to build a bomb would be an impossible task (see Margaret Gowing's Niels Bohr and Nuclear Weapons, in Niels Bohr: A Centenary ...


8

(1) Weapon-grade uranium is hard to make - it took almost a year to separate 64 kg of weapon-grade uranium for the bomb, so "Little boy" bomb was not even tested (they had no spare). And because of the bomb design, most of that expensive uranium was NOT involved in the nuclear explosion (bomb exploded into sub-critical mass before most of the uranium was ...


8

The sources are abundant and easy to find, for example Leslie Groves, Now it can be told. A history of Manhattan project (written by a project leader from the military side), Robert Jungk, Brighter than a thousand suns, (written by a journalist). Besides this there are literally hundreds of books, including many participants memoirs, describing in great ...


7

You should do some preliminary research before asking such a question. It was not so easy, even in theory. They did not know anything about Plutonium when they started, it simply did not exist. They had to make it, and study its properties etc. This was a slow process. The first bomb was based on Urainum rather then Plutonium, and again there was a huge ...


6

A side note first - when dealing with non-physicists, they will generally regard quantum mechanics as the end-all-be-all of physics, the coolest weirdest stuff. So, it is not surprising that your colleague focused on quantum mechanics and the rest was just engineering. So, lets look at your list first, then go on to some others of note that worked in the ...


6

On my opinion, there are two important reasons: a) German government did not press the matter. Nobody convinced it that the thing is plausible and important. (In the US there was a lobby who could convince the US president in this. Szilard, V. Bush and Einstein played an important role). b) I think even if they wanted, they could not do it. They simply ...


5

Historically, the discovery of naturally-occurring isotopes of chemical elements by means of the mass-spectrograph provided a correct explanation for the fractional character of the experimentally-measured values for the atomic weights of many chemical elements -- as compared with values that might have been expected if the atoms of a given element had been ...


5

Only after the neutrino's discovery did we come up with the concept of lepton number (based on the unexpected multiple lepton families), which warranted reclassifying "that other thing emitted in beta emission", which was how we originally defined the word neutrino, as an antineutrino. Ironically, there's still an outside chance the neutrino is its own ...


4

I found the following at an AIP site on Marie Curie, apparently a copy of an article of hers in Century Magazine, pp 461-466 (January 1904). It appears to be a non-technical journal: Radium possesses the remarkable property of liberating heat spontaneously and continuously. A solid salt of radium develops a quantity of heat such that for each gram of ...


4

Google Ngrams are based on searching mentions in book hits from the corresponding time period. By looking at the titles and contexts where the word is mentioned one can usually figure out what the dominant reason for its occurence is. Here is the Ngram for neutron and here are the book hits for the 6 year range around the spikes in 1957 and 1961. ...


4

I can only recommend R. Rhodes, The Making of the Atomic Bomb once more and very strongly. It is also instructive to note that although Leo Szilard [sp] was inspired to understand and fight for the chain reaction concept and also held the patent it was years before he or anyone else could figure out what material could be used to demonstrate the concept. Now,...


4

The website http://manhattanprojectvoices.org is full of interviews with participants in the Manhattan project. Some interviews address exactly the question asked here. For example, here are two interviews with members of what was called the "Special Engineering Detachment" in which the interviewed described quite specifically at what moment they were told ...


4

New scientific and engineering personal arriving at Los Alamos were given a series of lectures about the project, the relevant physics and the proposed designs of the weapons. These were later published as the Los Alamos Primer. So at least in Los Alamos, the purpose of the bomb was understood by all the technical personnel. Indeed, the ability to do so ...


2

The above photo was reproduced in the biography: Lise Meitner, A life in Physics, by Ruth Lewin Sime; University Of California Press,1996, ISBN 0-520-20860-9. A brief description of the parts is given on page 371, bottom and 372 top. The attached photo, describing some of the components, is from those included with the text.


2

I've never heard of a physicist denying the possibility of building atomic weapons. The closest thing that I am aware of is Werner Heisenberg's statement “I don't believe a word of the whole thing,” concerning the use of atomic weapons in Japan. But he was not denying the possibility of building the weapons. He just did not believe that the Americans had ...


2

By accident I stumbled upon a recent article about the topic in a german science journal: http://www.spektrum.de/magazin/warum-es-hitlers-atombombe-nie-gab/1427403 It is based on a the following publication: Popp. M.: Misinterpreted Documents and Ignored Physical Facts: The History of "Hitler’s Atomic Bomb" Needs to be Corrected. In: Berichte zur ...


2

I think it's pretty obvious (at least in hindsight and having read Richard Rhode's excellent history ) that they simply didn't know the total mass (fissile plus compression explosives plus shell) of the final device. Side note - the destructive force is much greater when a bomb is detonated at a calculated altitude rather than ground level. They probably ...


1

The question really hangs on when nuclear energy was thought possible; because once it is thought possible it's easy enough to speculate whether it could be weaponised. Now, in 1896 Wilhelm Rontgen and Henri Bequerel discovered radioactivity, and then in 1903 Pierre Curie announced that Radium salts radiated heat without cooling down and thus revealing a ...


1

I want to understand the extent to which scientists and technicians employed in the Manhattan project understood that they were building a bomb that would kill hundreds of thousands of people. There are two separate questions here: (1) whether they knew it was a bomb, and (2) whether they knew it would be used to kill large numbers of civilians. Even the ...


1

As regards the Soviet's quick progress on the bomb please read Dark Sun which is Richard Rhodes second book on the making of the atomic bomb. Early on he describes the wholesale shipping of plane loads of secrets to the soviets by their well respected U.S patriot spies here. The reasons given are well considered but unmentioned is Hitler's impatience which ...


1

Given enough time and resources, the Germans would have produced a bomb. What held them back was firstly that they were persecuting a large section of their existing scientific and engineering community (many literally going up the chimney) - either for their political views (socialists and communists) or because of their ethnic background (Jews). The ...


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