Did the Nazis Build an Atomic Bomb?

For years historians had argued that the Nazi effort to build an atomic bomb during World War II was far behind that of the Allies. Then in a controversial 2005 book, historian Rainer Karlsch made a startling claim…

On March 4, 1945, Clare Werner was standing on a hillside in Thuringian, Germany. Not too far away was the military training base near the town of Ohrdruf. Unexpectedly there was a flash of light. "I suddenly saw something," she said, " ... it was as bright as hundreds of bolts of lightning, red on the inside and yellow on the outside, so bright you could've read the newspaper. It all happened so quickly, and then we couldn't see anything at all. We just noticed there was a powerful wind..."

In the days that followed Werner complained of nose bleeds, headaches and pressure in her ears. Was what she witnessed the test of a nuclear weapon by Nazi scientists? How close did Hitler come to having a working atomic bomb?

Discovery of Fission

In 1938, two Germans, Otto Hahn and Fritz Strassmann, working at the Kaiser Wilhelm Institute in Berlin, discovered that when they bombarded uranium with neutrons they could split the uranium atoms' nuclei into two parts releasing energy and more neutrons (a process called fission.) From this it was obvious to scientists around the world that it was possible to create energy-producing fission chain reactions as the neutrons from one split-atom plowed into surrounding atoms, splitting them also. A controlled chain reaction could be used for constructive purposes like making heat that could be used to produce electricity. An uncontrolled chain reaction, however, would be a bomb of incalculable power.

As World War II appeared on the horizon, scientists in the United States, Germany and other nations, approached their governments, warning them of these developments. At the time the state of physics research in each country was roughly on par. If this was the case, how come United States and its allies went on to develop the atomic bomb and Germany didn't?

Incompetence, Conspiracy, or Neither?

In the half-century following the war, several theories arose to explain the lack of German success. Samuel Goudsmit, a member of the Allied scientific intelligence mission that investigated German progress on a bomb, came to the conclusion that the German scientists working on the project simply didn't have the understanding necessary to build such a weapon. In other words, Goudsmit claimed that these scientists, all approved to work on the project by the Nazi government, were simply incompetent.

His thinking may have some support in recordings made in 1945. After Germany surrendered, German physicists involved in uranium research were rounded up and detained at Farm Hall in England. Their conversations were secretly recorded in hopes of finding the state of Nazi research in physics. Of tremendous interest to the British was the scientists' reaction to the news that the Allies had dropped an atomic bomb on Hiroshima. Werner Heisenberg, the head of the German program at Kaiser Wilhelm Institute, was initially amazed at the success of the Allies program. He immediately tackled the question of how much uranium 235 (the only isotope of uranium which would work as a nuclear explosive) would be needed to build a bomb and came up with a figure of over a ton - way too high. It is from this mistake that many experts have formed the opinion that Heisenberg did not really understand how a bomb would work. However, Heisenberg corrected his estimate within a few days. Also, comments by Otto Hahn, who was another scientist interned at Farm Hall, suggests that Heisenberg had earlier, back in Germany, made the correct calculations. Perhaps he was now hiding his knowledge thinking that he and the other scientists were under surveillance, which indeed, they were.

As additional evidence of the German lack of understanding, Goudsmit argued that the Germans did not appreciate that the element plutonium could also be used to fuel a bomb. Documents recently found in Russian archives, however, clearly show this idea to be false. In 1941, Von Weizsäcker, a colleague of Heisenberg, wrote about plutonium in a patent application, "With regard to energy per unit weight this explosive [plutonium] would be around ten million times greater than any other [existing explosive] and comparable only to pure uranium 235."

Another popular theory is that Heisenberg actually sabotaged the German atomic bomb program because he didn't want Hitler to win the war. This idea originally was presented in a 1958 book by Robert Jungk called Brighter Than a Thousand Suns: A Personal History of the Atomic Scientists. Heisenberg did nothing to dissuade Jungk of this idea and later hinted that in a now famous September 1941 meeting with his old mentor, Niels Bohr, he had suggested that he was willing to join an agreement among all physicists to deny these powerful new weapons to all governments. This assertion is echoed in Thomas Power's book Heisenberg's War and Michael Frayn's play Copenhagen. Niels Bohr never publicly spoke of the meeting, but papers found after his death tell a different story: Heisenberg was willing to work with the Nazis and wanted Bohr to join him.

The real reason that the German effort was not successful, however, probably had nothing to do with either a conspiracy by scientists to withhold the weapon or a miscalculation by Heisenberg in building one. Early in 1942, German Army Ordnance completed a report which ranked weapons programs by how promising they were. Based on the information available at the time, it seemed unlikely that a nuclear bomb could be developed in less than two years. The German belief that the war would be over in two years steered the Army to only invest in weapons programs that could be completed within that period.

It is unknown if Heisenberg himself made this time estimate, but it appears to be scientifically accurate and consistent with predictions made by Allied scientists. The Allies, however, concerned that the war would go much longer than two years, and that the Germans might be able to produce their own nuclear weapon, invested heavily in building such a device. Ironically, unknown to the Allies, the German program had been put on the back burner and was not a real threat.

An Industrial Project

Even if the Third Reich had decided to build an atomic bomb, it might have been beyond German means. The Allies' Manhattan Project, which created their nuclear weapons, was just as much of an industrial effort as a scientific breakthrough. The project cost the equivalent of $30 billion in today's dollars and employed 125,000 people. Vast amounts of complex machinery and sprawling factories were needed to turn out the rare uranium 235 and plutonium necessary to fuel the bombs. Germany just didn't have the industrial capacity to support such an undertaking during the last years of the war.

Even if they had attempted it they would have found their factories exposed to constant Allied bombing attacks. The Allies, on the other hand, could place their project facilities deep in the heart of North America (in places like New Mexico and Tennessee) far from observation and interference by the Axis powers. So it appears there was really little chance of the Nazis actually developing an atom bomb during the war. They didn't even come close… or did they?

Karlsch's Zombie Bomb

German historian Rainer Karlsch, thinking about these issues wrote, "It would be rash indeed to believe that this is the last word on the matter. The German atomic bomb is like a zombie: just when we think we know what happened, how and why, it rises again from the dead." Karlsch resurrected the latest zombie himself when his book, Hitler's Bombe, was released in 2005. The book presents evidence that a second team of scientists under the direction of army physicist Kurt Diebner was much more oriented toward a weapons program than the Heisenberg group and had more success. Karlsch contends that this group was designing a bomb that used both nuclear fission and fusion (like that in an H-bomb) principles to release energy. He further suggests that this type of device was tested three times shortly before the end of World War II. One test occurred on the German island of Ruegen in the fall of 1944 and two more in the eastern state of Thuringia in March of 1945. While Karlsch doesn't say that the tests were entirely successful, he does believe that 700 people (mainly prisoners) died in the blasts.

After the publication of his book, Karlsch also found portions of a document written just after World War II by an unknown German scientist. A diagram found in these notes shows a sketch of a nuclear device very similar to the one Karlsch thinks was tested. Physicists that have examined the diagram don't believe it would actually have been capable of functioning, but Karlsch argues that the success of the weapon isn't the point. "…what is important," he writes in an article in PhysicsWeb with co-author Mark Walker, "is the revelation that a small group of scientists working in the last desperate months of the war were trying to do this."

Dirty Bomb

Another piece of evidence Karlsch points to is a Russian report written by Soviet spies. The report warns the Soviet leader, Stalin, that the Germans "detonated two large explosions in Thuringia." According to the report, these bombs probably contained uranium 235 and produced a "highly radioactive effect." The report goes on to say that prisoners of war housed at the location were killed, "and in many cases their bodies were completely destroyed."

Critics of Karlsch's work cite inconsistencies in his theory. For example, the bomb the Soviet report describes is not really a nuclear weapon because it does not use radioactive material to fuel the blast. It was, what would be called today, a "dirty bomb:" a conventional weapon laced with dangerous radioactive material to poison the surrounding area. This does not fit with the description made by Clare Werner of the test at Thuringia, which sounds more like a true atomic blast. Almost all parties agree, however, that Germany at that time did not have either the necessary uranium 235 or plutonium to build a true atomic bomb that could create such a fireball.

In February, 2006, scientists from Physikalisch-Technische Bundesanstalt in Germany traveled to Thuringia and took samples of soil to see if there was evidence there of any kind of a nuclear blast. Their reported revealed no abnormal background levels of radiation, other than those elevated as a result of the Russian Chernobyl reactor accident in 1986. Still, the report emphasizes that the tests do not disprove that there was an atomic blast at that location. It simply shows that there is no evidence in the soil to to support such a claim.

Even if you doubt Karlsch's theory, however, there is one area where you must agree with him: we have not heard the last word on this subject. There appears there is still some room left in the mists of history for the Nazi atomic bomb to rise from the grave at least one more time.

Karlsch found a sketch made by an unknown German scientist that looks like a diagram for an atomic bomb.

Copyright Lee Krystek 2007