In a review of John Adams’ new opera, “Doctor Atomic,” mention is made that Teller warned that a misstep could ignite the Earth’s atmosphere. Did he really have that fear, or is that just artistic license? And if it’s true, what did he not understand, or what was his misconception that led him to such an erroneous conclusion? Or what misstep did he fear?
According to the DOE, it was Fermi who was taking bets on whether or not the device would ignite the atmosphere.
Fusion wasn’t well understood at the time. Some of the early ideas for the “super” demonstrate this.
Ok, then. Whoever. More precisely, my question is what did Fermi/Teller believe to be true about the reaction and what did they believe to be true about the atmosphere that would make that bet even remotely feasible? I mean, “ignite the atmosphere” is a pretty bizarre notion. What did they believe that led them to that notion? No one today would suggest that the atmosphere could be ignited, would they?
The question was whether the device could produce temperatures and pressures high enough to start a self-sustaining fusion reaction in the Earth’s atmosphere, like the hydrogen flash sometimes seen on the surface of stars.
Given the data they had at the time, it was not an unreasonable assumption that a fission reaction might start a runaway fusion reaction. Fermi felt the odds were against it, but hey, they were pushing the envelope with all this stuff, so who really knew?
Hindsight’s always 20/20.
Dating the concern to Fermi’s betting pool at Trinity seriously misses the actual sequence of events. Offering this as an option in July 1945 was a joke. Though there are eyewitness reports that General Groves, the head of the Manhattan project, repremanded someone for frightening the enlisted men at the site by making this a subject for humour.
Teller’s concern about a fission weapon igniting the atmosphere actually dates to July 1942, when Oppenheimer was running a summer school on bomb physics at Berkeley. This is when Teller first seriously raised the notion of the Super, with the possibility of igniting the atmosphere with a fission device then following as a possibly analogous process. Teller himself, at least in retrospect, played down the significance of the suggestion in his memoirs. But the possibility seemed sufficiently serious to Oppenheimer that he traveled across country to warn Arthur Compton in Michigan (as related by Compton in memoirs, Atomic Quest, Oxford, 1956, p127).
Oppenheimer’s other action on the matter was to set Hans Bethe the task of assessing the issue - no doubt because, not only was he to hand, he was the world’s leading expert on fusion reactions at the time. In fact, Bethe “didn’t believe it from the first minute” and his detailed calculations only confirmed this.
There was thus a brief panic about the issue in the summer of 1942, but none of the physicists regarded it as a serious possibility thereafter. Hence Fermi’s joke.
On the general point of Doctor Atomic, Adams and Sellers have constructed the libretto from existing texts, though some have no otherwise obvious connection with the subject. Based on the coverage I’ve seen, they’ve clearly taken liberties with the details, but no more than I’d expect given that it’s an opera. As someone who both has an interest in the subject matter and who is an Adams fan, I’m very interested in seeing how the project works.
I’m very interested in this opera too. I hope I can get to see it around here somehow.
Realising that I didn’t actually answer the specific question in the OP …
I’m not sure that there’s any definite evidence for what Teller’s argument in July 1942 was in any detail. Coupled with the fact that he subsequently displayed a distinct track record for overestimating the likelihood of fusion - whatever the scenario, he usually thought it possible, whether it actually was or not - I’m also not sure there’s any terribly great need to explain what it might have been.
Thanks, all. It does fascinate me that whatever WAS known in 1942 was primitive enough to permit a top physicist - one who clearly understood the mathematics and physics of nature enough to create the fission bomb - to surmise that fusion reactions in the atmosphere could occur. In an imperfect analogy, it seems similar to, say, a surgeon discussing how he intends to do a partial liver transplant, but at the same time he worries that he might accidentally upset the balance of humors in the patient.
And so Teller, knowing that hydrogen atoms could fuse into helium, releasing enormous amounts of energy, believed that virtually any atoms could do the same thing? How did he know enough about H and He to make a bomb, but not enough about N or O?
If your post and the TV conversation between Buckley and Teller that I watched are indicators, sometimes Teller spoke before he thought.
In the Buckley show the use of the atomic bomb came up. Teller stated that in retrospect he thought maybe we should have demonstrated a bomb at high altitude near Japan first. Buckley pressed him for some details on how this would work. Teller than said that one way would be to have detonated an A-bomb at 40000 ft. off the coast in the vicinty of Yokohama. On hearing this I almost came right out of my seat, but Buckley took it in stride apparently thinking that we could have done such a thing in 1945.
At that time we had no airplanes that could carry the A-bomb to 40000 ft. And we had no way of releasing it and holding it at that altitude before detonation so that the release plane could escape the blast.
Many elements can fuse and release energy, including N and O. In general, any element lighter than Fe can support an energy producing fusion reaction. This can be seen in the evolution of stars.
From what I’ve read, the design of the super presented two major problems. Generating temperatures and pressures sufficient for fusion, and preventing the reaction from fizzling due to energy loss from EM radiation.
Knowing that something is possible and designing a workable device are very different things.
In his first autobiography, Richard Feynman indicates that while a few folks took the concept of an exploding Earth seriously, most of them didn’t that someone there had (IIRC) done the math and figured out that it couldn’t happen.
I was completely astonished when I first heard about this concept. Fuck the moral issue about dropping an atomic bomb on a city. I just can’t comprehend how these people tested a bomb while thinking that this could result in igniting the athmosphere. Regardless how remote and unlikely this risk was, it appears to me to be complete craziness to roll the die with such an idea in mind.
One day, the last sentence pronounced will be “you know, I had this weird idea that this thing could…”, just before the spatio-temporal fabric of the universe will be ripped apart.
But that wasn’t what happened. Read the paragraph beginning “Oppenheimers other action …” in this post.
The story, as related in Richard Rhodes The Making of the Atomic Bomb, is that Teller guessed that this might be an issue. Susequent calculations by other Manhattan Project workers showed that it was nearly impossible. Then Teller and Fermi got to joking about it, and Groves made them stop.
Teller was right to be concerned, and had the justification initially. When he first spoke, they had not even done the first controlled fission reaction. Here they were planning a bomb. Nobody knew if it would fizzle, work, or go out of control. It was as if they had just discovered fire, and were now planning to attack Japan with firebombs.
Read anything about the first work, and you’ll find that it was filled with guesses, estimates, and overkill, just to hedge bets towards getting a bomb that worked. The estimates were so crude that sometimes they had a leeway of 2 orders of magnitude!
It’s also true that Teller liked to talk, particularly about himself. Another scientist might have been more circumspect.
I don’t think that Oppenheimer, Fermi, or Bethe would have allowed the testing to go forward if they’d been worried about fusing the atmosphere. I suspect that Teller might have!
Well, as Terry Pratchett so charmingly put it:
With our luck, though, it’ll be a redneck, and the actual last words will be “Hey, y’all, watch this!”
Well, Teller didn’t know how to build an H-bomb in 1942.
It was common knowledge amongst physicists by this time that fusing any element lighter than iron would release energy, but that high energies were needed to force the atoms to the point where this could happen. Teller’s insight - which had occured to a few others independently - was that a fission bomb might heat up nearby material to the point where its atoms had enough energy to do so, producing a fusion bomb. For that to happen in a particular material requires that the fission trigger reaches some minimum temperature, which will be different for different fusion fuels.
In July 1942, Teller was severely underestimating this required minimum temperature for all potential fuels. A fission bomb would be producing far higher temperatures than Teller’s minima, regardless of the potential fuel. That made a hydrogen-fueled fusion bomb look easy. It also made it pretty much as easy to envisage triggering a fusion reaction in nitrogen as hydrogen.
The concern he then raised was that such a fusion reaction outside the bomb might be self-sustaining: fusion in the material nearby would release energy which would heat up the material next to it and so on, indefinately. As mks57 notes, the energy released can also be lost as radiation. So whether the runaway reaction happens is, very roughly, a question of two things: how much radiation is lost and what’s the minimum temperature that you need to acheive fusion in a particular material.
Teller was screwing up both aspects - and both in the direction such that both a fusion weapon and a fission bomb igniting the atmosphere were more likely. Bethe’s better calculations were mainly directed at these issues with nitrogen as the fusion fuel and, as explained in the earlier post, it’s at this point that everybody - but see below - realised that Teller had been wrong and that there was no danger.
As an incidental matter, Bethe’s analysis also made a hydrogen bomb much harder to envisage. It was back of the envelope stuff even in 1942 to show that there was a vast difference between igniting nitrogen and igniting hydrogen. The situation thus became that an H-bomb was now far less likely to be feasible than Teller had initially suggested, but in ruling out igniting the atmosphere Bethe wasn’t necessarily ruling that out. To a large extent, the pattern at repeated was that Teller argued that, with the right design, an H-bomb was feasible, while others usually disagreed and could point to reasons why whatever his current design wouldn’t work. You might say that people quickly realised that even a hydrogen-fueled fusion bomb was hard to build. They’d realised that a fission bomb couldn’t even ignite an “atmosphere” of hydrogen, even if you considered expedients like freezing it, never mind one that’s mainly of nitrogen. Fusion is hard to get going for any length of time. Teller still didn’t know how to build an H-bomb into the Fifties.
Even knowing that an H-bomb can be built actually doesn’t change the issue. None of the successful designs have anything in common with what he was envisaging in 1942. Basically, knowing exactly what they’re doing and setting up exactly the right circumstances, human beings can only ignite fusion reactions in relatively small quantities of light elements.
I’ll take this opportunity to add a couple of complicating comments to my previous posts, based on a number of a number of details I’ve come across in the weeks since.
The thread prompted me to later have a glance at Peter Goodchild’s recent biography of Teller - I don’t have a copy to hand yet - to check what he had to say on the July 1942 flap. He points out that Teller himself later systematically played down the incident, saying that even he had never taken the possibility seriously. Goodchild even suggests that this marks the point at which Teller retrospectively started constructing his own self-justifying history of the development of the H-bomb. However, his references on the point are all to the Memoirs - which I don’t have to hand either - and I haven’t got round to checking Goodchild’s comments against that yet; it’s on my vague “to crosscheck at some convenient point” list.
On the subject of Goodchild, his previous take on the incident in his old 1980 biography of Oppenheimer (the tie-in to his BBC series) had been to suggest that it was significantly more serious than I stated above. But I never thought his supporting evidence really proved anything. He argues that the fact that Bethe’s conclusion was classified meant that the possibility was repeatedly independently re-raised in later years and states that Oppenheimer asked Teller to redo Bethe’s analysis in early 1945 as a further check. In his view, the issue rumbled on at some level until the Trinity test. Yet the fact that others, outside of Los Alamos and ignorant of Bethe’s refutation, raised the issue later doesn’t really prove that the issue should have been of greater concern to those who were taking the key decisions. His source for the Teller recheck was presumably Teller himself and that probably colours the description of what happened.
That the issue was raised independently later is confirmed by Maurice Wilkins in his autobiography The Third Man of the Double Helix (Oxford, 2003; 2005, p82), which I coincidentally happened to be reading recently. Having worked on the issue under Oliphant in Birmingham, he was sent to Berkeley in February 1944 to help with isotope separation. While there he heard a talk by a “distinguished German woman scientist” about the possibility, though he didn’t take the idea seriously. I suspect he was implying that it was Maria Goeppert-Mayer, later a Nobel winner, who gave the talk. She didn’t primarily concentrate on nuclear physics until afterwards, but she had worked on the subject of fusion in the Thirties and on Teller’s Opacity Project during the war. That stuff was directly relevant to the question and, if she did give the talk Wilkins heard, one does wonder what Teller knew about what she was going to say.
These details are still just loose ends and the basic conclusion - that those most informed had no reason to be concerned after the 1943 fuss - stands.
As noted above, many of Teller’s statements about his life have to be treated with caution. Though, in fairness, there is independent contemporary evidence that he did advocate some demonstration in 1945 before being talked out of it by Oppenheimer. I’m not sure what he had in mind at the time, but I can see him trying to bluff an example when pressed.
No one is saying that he didn’t advocate a demonstration. Only that the demonstration that he proposed on Wm. F. Buckley’s show, Firing Line, in the mid 1980’s was impossible for the US, or probably anyone else, to do in 1945.