March 8, 1879, Frankfurt am Main (Kingdom of Prussia, German Empire) – July 28, 1968, Göttingen (Lower Saxony, Federal Republic of Germany)
He studied chemistry in Marburg and Munich and, after receiving his doctorate in 1901, worked at the University of Marburg.
In 1904, he moved to London and a year later to Montreal, finally settling in Berlin.
Together with Lise Meitner and Otto von Baeyer, he developed a technique for measuring the beta decay spectra of radioactive isotopes. Recognition for this achievement secured him a teaching position at the Kaiser-Wilhelm Institute of Chemistry in Berlin in 1912.
In 1918, he and Meitner discovered protactinium.
When Lise Meitner fled Nazi Germany in 1938, Hahn continued to work with Fritz Strassmann in elucidating the result of thermal neutron bombardment of uranium. He reported his results, the discovery of the elements barium and krypton, to Meitner who, in collaboration with her nephew Otto Robert Frisch, correctly interpreted them as evidence for nuclear fission.
Once the idea of fission was accepted, Hahn continued his experiments and showed that enormous amounts of energy were released in neutron-induced fission and could be of use to mankind.
During World War II, Otto Hahn was under surveillance by the allied ALSOS program as he was believed to be involved in the German project to develop a nuclear bomb although his only connection was the discovery of fission because he never worked on the project.
In 1944, he received the Nobel Prize in Chemistry for his pioneering work in the field of radioactivity, discovering the nuclear fission of uranium and thorium in 1938, albeit omitting the fundamental contribution of his colleague, Lise Meitner.
When it was granted, he was a prisoner of the British, who were seeking information on the failed German effort to develop an atomic bomb. Faced with this situation, they allowed him to write a letter accepting the award, but in which he apologized for not being able to attend the delivery.
After the war, he was very active politically, especially on issues related to world peace and social justice, and stood out as a staunch opponent of the use of nuclear weapons.
There were proposals that elements 105 and 108 of the periodic table be named Hahnium in his honour, but neither was approved and they were named Dubnium and Hasium, respectively. However, one of the few nuclear-powered merchant ships in the world was named after him in his honor.