Boffey, Philip M. "Still a Mystery: Nazi Germany's Atomic Bomb Failure," New York Times,
10 February 2002, p.WK14.
The small trove of documents released last week throws cold water on the notion that high-
minded German scientists tried to slow work on an atomic bomb for the Nazi regime during
World War II. But the documents provide no definitive answer to the question of why German
physicists, who were among the best in the world, made so little progress on the atomic weapon
compared with their counterparts in the United States.
The idea that German scientists worried about the morality of atomic war and tried to head off
the development of a bomb was given wide currency in "Copenhagen," Michael Frayn's award-
winning play, which focuses on a pivotal meeting in September 1941 between Werner
Heisenberg, the scientific head of the German nuclear project, and Niels Bohr, his Danish
mentor. Both were Nobel laureates and towering figures in 20th-century physics.
The play is built around the differing recollections of the two men and the ultimate uncertainty of
exactly what happened. In it, the Heisenberg character explains that he visited Bohn to warn him,
in highly guarded language, that atomic bombs could be built and to feel him out on whether
physicists on both sides could agree to stop the work. The Frayn play was greatly influenced by a
book that argued that Heisenberg and his colleagues actually sabotaged the German bomb
program from within, a view that is accepted by few historians who have looked into the
The puzzle as to why the German atomic bomb program stalled has several overlapping
explanations. Some of the best German physicists were Jewish and had been driven into exile,
where many worked on the American or British atomic bomb programs. Nazi ideology had only
scorn for "Jewish physics" and thus undervalued what theoretical physicists could contribute to
the war effort. And as saturation bombing ravaged German cities, the Nazi industrial machine
increasingly lacked the ability to mount a vast bomb development project to compete with the
American Manhattan Project
Still, it is clear that German physicists, for whatever reason, did fail to push hard enough to reach
the goal. Some attribute that to surprising technical errors, like a grotesque overestimate of the
amount of fissile material that was needed and a failure to realize that readily available graphite,
if high purified, could be used to moderate the atomic reaction instead of scarce, hard-to-get
heavy water. Others blame arrogance and complacency on the part of German physicists who felt
that if the job was hard for them, it would be impossible for the Allies. And some believe that
there was a genuine reluctance to work on such an awesome weapon, either mor moral reasons or
for fear of failing and being blamed for a national defeat.
Recordings made surreptitiously of Heisenberg and other German scientists held in captivity after
the German surrender show that they were stunned by news that the United States had exploded
an atomic bomb over Hiroshima and refused to believe that it had actually been done. Even in
these early recordings, one can discern the beginnings of a search for the moral high ground, as
one German physicist contrasts the American development of "this ghastly weapon of war" with
more peaceful nuclear reactor research under Hitler.
Heisenberg's own version of his meeting with Bohr was set out years after the war in a letter than
was excerpted in a book on the atomic bomb projects. He recalled starting his conversation with
Bohr by raising a question about whether it was "right" for physicists to work on uranium during
the war, given that it could lead to "grave consequences." He also said he had told Horn that
developing atomic weapons would require such a terrific technical effort that one could hope
they would not be ready in time. He felt the situation gave physicists leverage to dissuade
government officials from even trying to built the bomb.
That letter so angered Bohr that he drafted a number of responses between 1957 and 1962 that
were never sent but were released last week by the Bohr family. As Bohr recalled it, Heisenberg
left "the firm impression that, under your leadership, everything was being done in Germany to
develop atomic weapons." Bohr said that Heisenberg "gave no hint about the efforts on the part
of German scientists to prevent such a development."
Even with these latest documents, we are still left with conflicting bersions from the two
participants. Most historians seem inclined to accept Bohr's version as more probably and
Heisenberg's as revisionist history, a view that gains credence by looking at Heisenberg in a
broader context than just that single meeting.
David Cassidy, a historian at Hofstra University who wrote a biography of Heisenberg, says there
is no evidence from any other sources that moral issues were of particular concern to Heisenberg.
Indeed, he says, Heisenberg seemed most concerned about using the war to prove the worth of
physics to the nation and its rulers. With those motivations in mind, it seems likely that
Heisenberg would have made a bomb if he could.