Did Germany's top physicist kill the bomb project?





Thomas Powers.


' 585 pages. $27.50.

During World War II, U.S.-based scientists worked feverishly to develop the atomic bomb. Their fear was that if Hitler won the nuclear race, Fascism would rule all of Europe.

Their concern focused on the scientific genius of one man, German physicist Werner Heisenberg. By 1939, the theory of nuclear fission -- with its potential for destruction and as a future source of power -- was well known to a small group of scientists, including the Nobel laureate Heisenberg.

Heisenberg contributed to the American scientific community's apprehension, when, during a visit to America in August 1939, on the eve of war, he announced that it was his patriotic duty to return to the Fatherland. The Americans also knew that Hitler controlled uranium oxide ("yellow cake") mines in occupied Czechoslovakia. This, coupled with a strong German industrial base, added up to a nuclear threat.

Thomas Powers, author of this well-researched book, attempts to show why, despite these advantages, Germany did not build the bomb.

Heisenberg came from a family with an academic background, as he recalled to me during an interview at Harvard in April 1973, when he was visiting the United States.

He said: "I was born in the year 1901 in a small town in Bavaria. At the time, my father was a teacher at the [high school] in Wuerzberg. When I was about 8 years old, my father was transferred to Munich, and so the family moved to Munich. My father became a professor of medieval Greek literature. . . .

"I went to school in Munich and I very early developed an interest in mathematics and physics. . . . By the age of 12 or 13, I was studying differential and integral calculus.

"Then World War I changed our lives completely. Life was very hard at the time; food was in short supply and so, with my father's agreement, I went into the country. I worked as a farm laborer. At least I got enough to eat. And I can say that I enjoyed the hard work in the open air.

"By 1920, I was back in school. Professor [Arnold] Sommerfeeld suggested that since I had already done the mathematics that the university offered, I should study physics. I attended the professor's lectures on relativity, but soon understood that he was more interested in quantum theory."

A few years later Heisenberg met, and then worked with, Danish nuclear physicist Neils Bohr. From this relationship, the German physicist developed his concept of the Uncertainty Principle -- .. that one cannot simultaneously know the position and momentum of an electron at any given time. In 1932, he won the Nobel Prize in physics.

Since many German scientists had emigrated, Heisenberg remained his country's pre-eminent physicist. His very existence was considered to be a threat to the West. Two scientists, Hans Hethe and Victory Weisskopf, urged in October 1942 that Heisenberg be kidnapped during a lecture in Switzerland.

The question the book attempts to answer is this: Were their fears justified? Or, as Mr. Powers concludes, did Heisenberg kill the German bomb project?

During the April 1973 Harvard interview, I asked Heisenberg: "You worked with Neils Bohr; you knew of the dangers and promise of nuclear fission. You stayed in Germany. Why didn't Germany build the atomic bomb?"

He responded: "The question as to whether an atomic bomb could be built was discussed shortly before the war. For instance, [Enrico] Fermi and myself discussed the problem in the States in July and August 1939. Then, during the war, a number of physicists were told by the German government that they should study the possibility of applying atomic energy for technical purposes, one of which was the possibility of constructing atom bombs.

"Fortunately, already in our first discussions, we discovered that tomake atomic bombs from natural uranium was impossible. We also knew that in principle, one can make atomic bombs by isotopic separation. But, fortunately, that was a process that would require infinite technical effort that we hoped would not be possible during the war. . . .

"There was never an attempt to construct an atomic bomb simply for the reason that we knew and our government knew that the technical effort would be too much, too big for a country like Germany."

Heisenberg's story is not universally accepted. His former student, Edward Teller, told me that "Heisenberg did not really want to build the bomb." But the Dutch-born physicist Samuel Goudsmit contends that German scientists did try but failed early in the game because they committed serious technical errors.

It was clear then that before committing considerable time and money to the fission program, it was necessary to demonstrate that a controlled nuclear chain reaction was possible. In America, Leo Szilard insisted that ultra-pure graphite be used as a moderator in the nuclear pile, and the experiment was successful. Heisenberg did not insist on pure graphite, and the experiment failed. After this failure, he believed it would have been irresponsible to urge his government to commit scarce resources to the bomb project.

After the European war, when Heisenberg learned that America exploded the bomb, his first reaction was that the United States was bluffing. He later reversed himself and explained to his colleagues "how America built the bomb."

Thus it is difficult to accept Mr. Powers' conclusion that Heisenberg "killed" the German nuclear project. The physicist must have known when he returned to Germany that his government would want him to build the bomb. Still, he returned to Germany and lived there until his death in 1976.

Apart from this conflict, it is hard to criticize the book. It is well-researched, reads well, and deserves to be included in your library.

Mr. Blumberg is co-author of two books on Edward Teller. He lives in Baltimore.

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