An article of mine (“A Tale of Openness and Secrecy: The Philadelphia Story”) has recently been published in Physics Today. Even better, the article has been made available for free on the Physics Today website (and as a PDF), so it can be read widely.
Click to go to the article online.
The basic story is thus: in late 1945, a group of scientists at the University of Pennsylvania, led by one William E. Stephens, decided that it would be a really cool thing to write their own, heavily-technical version of the Smyth Report. They would show that a bunch of non-nuclear physicists could, from the published literature and first principles, explain in technical terms exactly how atomic bombs worked. By publishing this, they’d prove that there wasn’t any “secret” to the atomic bomb at all. But what started out as a statement about the futility of scientific secrecy quickly became a test of the limits of free discourse in the nuclear age.
These scientists were the unheralded predecessors of the Howard Morlands, Chuck Hansens, Carey Sublettes, and John Coster-Mullens of the world, but their story is basically unknown today, despite having lasting effects on the way that the postwar Manhattan Project and Atomic Energy Commission thought about secrecy. Their original goal — to show that clever outsiders could guess at secret things — definitely came across to the atomic officials, even if their denunciation of secrecy did not.
The final book was published as Nuclear Fission and Atomic Energy in late 1948 (two years after it was first written), and is now completely out of copyright. It’s not an interesting read, on the whole, though the forward and preface are interesting in respect to the purpose of the volume.
But the published version is missing part of the chapter on nuclear weapon design — the part that was “voluntarily” censored at the request of the Manhattan Project and AEC. The reason it was censored was because the scientists had managed to independently derive the idea of implosion. The implosion design (which was used in the Trinity “gadget” and the Fat Man bomb) was still considered secret at the time (it wasn’t declassified until 1951), so this was a pretty big coup on their part.
This week’s document is a true exclusive: the censored chapter from Nuclear Fission and Atomic Energy, taken from the AEC’s files. Stuck into the chapter was a note by William Waymack to Robert Bacher (AEC Commissioners both) decrying how irresponsible they felt the scientists were. (It is quoted, and partially photographed, in the Physics Today article.)1
Click the image for the PDF.
Everything from section 11.6 onward was cut from the final book (as can be seen from the Archive.org version of the book, linked to above). It’s the only part of the volume that was so censored, but it ends the chapter quite abruptly. I’ve marked the point of censorship in the PDF above.
It’s not a thrilling read — it is heavy on the math — except for the fact in that it actually talks about implosion (by name!) which is pretty big bananas for a bunch of scientists with no Manhattan Project connection in late 1945. The fact that they mentioned it by name was considered a particular indictment by MED and AEC officials — though they pointed out that it was a common technical term and was present in every decent dictionary.
The fateful word.
If there are any technical people reading, I’d love to know what you think about their reasoning here. I suspect it is actually not that great — that other than getting the general implosion concept, it is probably more revealing of their ignorance than their knowledge — but I’m not a technical person, so I don’t really know. My feeling is that while the point that trained scientists can independent re-derive and re-discover scientific “secrets” is largely correct, you probably can’t do it very well from a purely theoretical standpoint. (To their credit, the physicists admit this, especially when talking about critical mass estimates, since they could tell from the Smyth Report that so much hinged on getting very good neutron cross-section measurements.)
Some parting intrigue: the Library of Congress has a copy of this early draft as well in its main holdings… but somebody has long since torn out the pages in question. Spooky! I suspect the FBI — they were sent around in 1948 to round up any missing copies of the book, and the AEC had been told about the copies on deposit at the LOC — but I’ve no hard evidence on it.
An addendum: Yesterday evening, I received an e-mail from William Stephens’ son, thanking me for writing the article. He added a detail I hadn’t any clue about. At one point in the story, the Pennsylvania scientists go to New York to give a press conference denouncing atomic secrecy. Stephens’ son was born while he was away — on the same day. I love that detail; it adds a personal touch to a story which is otherwise composed of letters and memos. (Look for some more thoughts along those lines on Friday.)
- Citation: Chapter 11 from William E. Stephens, ed., Nuclear Fission and Atomic Energy (draft June 1946), copy in Records of the Atomic Energy Commission, RG 326, National Archives and Records Administration, Records of the Commissioners, Office Files of Robert F. Bacher, Subject File, 1947-1949, Box 3, Folder “Philadelphia Story.” [↩]
Despite the claim above, that’s actually extremely thrilling to read. But I’d guess a non-physicist would disagree. 🙂
They did actually pretty good job on identifying potential problems and possible fixes to them. They certainly were on the correct route for designing an implosion bomb. What’s left has more to do with running experiments to certify certain values (things like the critical mass experiment) and engineering a workable design based on the principles and results (which is no small feat, either). The whole theoretical framework is there.
Thanks, I appreciate the input!
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