— Are you telling me that there is a chance that by pressing that button we will destroy the world?
—The probability is almost zero.
—What do you want… We only have the theory.
— Nula would be better.
Throughout Christopher Nolan’s film about the development of the atomic bomb, there are few dialogues as intense as the one between General Leslie Groves and J. Robert Oppenheimer shortly before the Alamogordo test.
And it is logical. First, because what they both discuss, Leslie Groves with a heated and agitated tone that contrasts with the calm of Oppenheimer played by Cilliam Murphy, is the probability that the Trinity test ended setting the atmosphere on fire of our planet and turned the Earth into a huge pyrotechnic spectacle. Second, because with greater or lesser intensity such fear is much more than Nolan’s plot device: it existed and generated calculations… and headlines.
“The Manhattan Project scientists considered igniting atmospheric fires to be a serious possibility, although how they approached that possibility seems a matter of historical controversy,” Dongwoo Chung recalls in an article published on the Stanford University website. Even Arthur Compton, Bob Serber and Hans Bethe spoke on the subject, who years ago spoke at length about what happened in an interview collected by Scientific American. The tone of his stories, however, does not always match.
Bethe recounts how around 1942 Edward Teller showed up at Berkeley and dropped a plot bomb, a disturbing idea, at least on a theoretical level. “Well, what would happen to the air if an atomic bomb were exploded in the air?”, launched the physicist, today known as ‘the father of the H bomb’, to his colleagues: “There is nitrogen and you can have a nuclear reaction in which two nitrogen nuclei collide and become oxygen plus carbon, and in this process a lot of energy is released.”
Such a possibility led J. Robert Oppenheimer to consult Arthur Compton, and led to a series of calculations that, Bethe assures, soon reassured the project’s experts. “I sat down and analyzed the problem of whether two nitrogen nuclei could penetrate each other and cause that nuclear reaction. I discovered that it was incredibly unlikely“, he would relate years later.
His calculations and conclusions did not prevent, to relax the tension at Los Alamos, another of the participants in the project, Enrico Fermi, from posing a macabre bet to his colleagues: the possibilities that Trinity would end up setting the atmosphere on fire. “Some accepted,” jokes Bethe, who categorically guarantees that during the test in July 1945 he was absolutely sure that it would not break out. an apocalyptic reaction. “The only thing I had in mind was that maybe the launcher wouldn’t work because I had to do with its design. “It never occurred to me that it would set the atmosphere on fire.”
It is not the only story we preserve of what happened those days. Arthur Compton would also reflect on the fear of atmospheric ignition. In 1959, during an interview with American Weekly magazine, the 1927 Nobel Laureate in Physics spoke of the disturbing possibility slipped by Teller. And his words, at least as recorded by Pearl S. Buck, the writer with whom he spoke, point to a quite different tone: “It would be the definitive catastrophe. Better to accept the slavery of the Nazis than to run the risk of drawing the final curtain.” of humanity.”
“And if it is hydrogen, what about the hydrogen in sea water? Couldn’t the explosion of the atomic bomb trigger an explosion of the ocean itself? Nor was this all that Oppenheimer feared. Nitrogen in air is also unstable , although less so. Couldn’t it also be caused by an atomic explosion in the atmosphere?”, includes the story captured by Buck. The description was tricky enough that Bethe himself ended up coming out some time later to clarify that the American Weekly writer had “misunderstood” Compton and there was no “no possibility” of apocalyptic reaction.
Gadget, code name for the nuclear device.
“Teller posed the famous question of turning on the atmosphere. Bethe went on as usual, ran the numbers, and showed that it couldn’t happen. It was a question that had to be answered, but it was never anything, a question for a few hours. Oppy made the big mistake. mistake of mentioning it on the phone in a conversation with Compton and he didn’t have enough common sense to keep quiet,” explains Bob Serber: “Somehow he found a document that went to Washington. Someone noticed, the question arose and the thing was never left at peace.”
Actually the members of the Manhattan Project They weren’t the only ones. in fearing a scenario of apocalyptic repercussions. In the book ‘Inside the Third Reich’, Albert Speer, former Minister of Armaments and War Production in Nazi Germany, explains that the physicist Werner Heisenberg could not provide them with a reassuring answer about the safety of an atomic test.
“Heseinberg had not given any definitive answer to my question whether successful nuclear fission could be kept under control with absolute certainty or could continue with a chain reaction,” recalled Albert Speer in his 1969 book. “Hitler clearly I was not delighted with the possibility of the Earth under its control could transform into an incandescent star.” Recently the BBC published a report in which it explains how fears of reactions capable of destroying the Earth predate the first nuclear tests.
Because when talking about a possible apocalyptic explosion, however remote it may be, the most reassuring probability is “zero”, as Groves maintains.
Images: Los Alamos National Laboratory
In Xataka: Oppenheimer has gone down in history for the atomic bomb, but his greatest legacy was left in black holes