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Turing's Cathedral by George Dyson

Turing's Cathedral by George Dyson

Author:George Dyson [Dyson, George]
Language: eng
Format: epub, mobi
ISBN: 978-0-307-90706-6
Publisher: Knopf Doubleday Publishing Group
Published: 2012-03-05T16:00:00+00:00


Ulam spoke to Carson Mark and Norris Bradbury immediately, and Edward Teller the following day. Teller, who had been working on the problem for almost a decade, immediately improved upon Ulam’s suggestion, and brought in a young Viennese physicist, Frederic de Hoffmann, who performed the initial calculations establishing the probable feasibility of the new approach. “I wanted to do something about the hydrogen bomb and nobody else wanted to,” Teller says, “and the one man who wanted to do it more than I was Freddy de Hoffmann.”49 It was de Hoffmann, twenty years old at the time, who had calculated the ballistic trajectories for the two bombs that were dropped on Japan.

Teller titled his 1955 review of the H-bomb’s development “The Work of Many People”—a genuine attempt to share the credit, in the face of widespread criticism, with those who had helped. Hans Bethe wrote his own account in 1954, which he opened by giving Teller full credit, during the atomic bomb development, for being “the first to suggest that the implosion would compress the fissile material to higher than normal density inside the bomb.” But he refused to assign Teller chief credit for the breakthrough on the hydrogen bomb. “It is difficult to describe to a nonscientist the novelty of the new concept,” he wrote. “It was an entirely unexpected departure from the previous development. It was also not anticipated by Teller, as witness his despair immediately preceding the new concept.”50

Ulam suggested that overenthusiasm for the classical Super may have delayed Teller’s own arrival at a successful design, and emphasized that the real credit should go to “the enormous number of calculations, all the studies of the general physics of the processes, the engineering planning, all combined with the necessity of predicting and avoiding ‘side effects,’ any one of which could ruin the success of the device.” And if individuals were to be singled out, he noted to Bethe, “it would be hard to exaggerate the importance of the contributions made by Fermi in the decisive switch from the original, hopeless approach.”51

The breakthrough, now known as the Teller-Ulam invention, appeared in February 1951, and was published (in an edition of twenty secret copies) under joint authorship on March 9, 1951. “The arrangement might be called heterocatalytic, involving as it does a setting off of a reaction in one system by a reaction started in another,” Teller and Ulam explained.52 “This new idea transformed the concept of the Super into the beautifully workable hydrogen bomb,” says Harris Mayer, who helped resolve the details of a new concept that was “remarkably complex, and devilishly interesting.” Mayer’s specialty was radiation opacity—how some states of matter are more opaque to radiation at certain temperatures, and some less. Understanding the details can help tailor things so radiation flows where you want it to, and when it reaches its destination is either absorbed or transformed. “Nature had provided generous margins,” he says, “in the properties of radiation flow.” Mayer adds, however, that “nobody thought that Stan was the significant person in the new hydrogen bomb development until the Oppie affair.



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