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One day in July 1938, a car pulls up at the train station in Berlin. A woman climbs out. She shows her travel documents to the armed guards in Nazi uniform. The woman is small and slight, and she seems nervous. On the train she greets a man and they travel together, heading for Groningen in the Netherlands. Are they lovers, perhaps?
No, this is not a tryst but a rescue mission. The woman is an Austrian named Lise Meitner, and is one of the most brilliant nuclear scientists working in Germany. She is of Jewish descent and is fleeing Adolf Hitler’s regime when it is almost too late. The Nazi leaders have introduced a policy prohibiting all scientists from leaving Germany, and they have forbidden Meitner from gaining the documents that would offer her freedom to travel. At the Dutch border, a Nazi military patrol makes its way through the carriages of the train, checking documents. Meitner’s travelling companion, a Danish chemist named Dirk Coster, has negotiated permission from the Dutch authorities for her to enter the country. But all she has as identification is her Austrian passport – and it is obsolete. “I got so frightened, my heart almost stopped beating,” Meitner later recalled. “I knew that the Nazis had just declared open season on Jews, that the hunt was on. For 10 minutes I sat there and waited, 10 minutes that seemed like so many hours. Then one of the Nazi officials returned and handed me back the passport without a word.”
Minutes later, she was safely across the Dutch border. Once they arrived in Groningen, Coster sent a coded telegram back to Meitner’s former scientific collaborator in Berlin, chemist Otto Hahn, to say that the ‘baby’ had arrived.
When Hitler came to power a few years earlier in 1933, his anti-Semitic policies lost German science many great researchers. Most famously, Albert Einstein, who was on a tour of the US when the election result was announced, never returned. But few would have been as valuable to Germany as Meitner.
A few months after her dramatic escape from Nazi Germany, Meitner was living in Sweden. She was told about the latest results that Hahn had obtained in his work on the radioactive decay of uranium. And she realised what Hahn did not: that uranium was undergoing nuclear fission, splitting in half and releasing some of its tremendous store of nuclear energy.
Seven years later, on 6 August 1945, that same process of nuclear fission in uranium was triggered inside Little Boy, the bomb that was dropped over the Japanese city of Hiroshima. The rest, you might say, is history – except that it is a history still all too present today, when the threat of nuclear conflict lies once again over the world. It was Meitner’s insight that launched the nuclear age.
Meitner’s career launched in 1901, when she decided to start studying physics at the University of Vienna. After achieving a doctorate, she arrived in Berlin in…
Philip Ball’s Science Stories returns to BBC Radio 4 from 22 November at 9pm.