The uranium cubes that exposed Nazi Germany’s nuclear failure

During World War II, the United States raced to develop the atomic bomb partly out of fear that Nazi Germany might build one first. But how close did Germany actually come to achieving that goal? A new scientific investigation suggests the Nazi nuclear program was much further from success than its leading physicist claimed.

By examining surviving uranium cubes and previously documented historical evidence, researchers have uncovered major limitations in Germany's final experimental nuclear reactor. Their findings indicate that the project was not simply missing a few materials. The reactor would have required far more uranium and heavy water than Germany had available during the war.

The Manhattan Project, the secret American effort to develop nuclear weapons during World War II, was driven partly by the possibility that Nazi Germany might achieve a similar breakthrough first. Scientists knew that whoever succeeded could gain an unprecedented military advantage.