He returned to the University of Manchester, where he stayed from 1914 until 1916 as a lecturer. The confirmation was received in 1916, and Bohr returned to Copenhagen as professor of theoretical physics. In 1917 he was named a member of the Royal Danish Academy. He began work on planning an Institute of Theoretical Physics in Copenhagen, which opened in 1921. Bohr became the institute's first director. He remained there for the rest of his career. The institute was popular among physicists and welcomed visiting researchers.
In 1922, Bohr won the Nobel prize in physics for his work on the atom. His other research included the principle of complementarity, a theoretical description of the periodic table of elements, a theory of the atomic nucleus as a compound structure, and the function of the isotope 235 in uranium fission.
The Nazis entered Denmark in 1940. Bohr's position became uncertain since his mother's family was Jewish. Bohr learned from Lise Meitner, who had fled Nazi Germany, that the Germans were trying to split the atom. In 1943, he and his family escaped to Sweden on fishing boat, and then he and his son Aage flew as secret passengers in an unarmed military plane to England where he began working with a team trying to create a nuclear fission bomb. Within months, he and Aage moved with the team to Los Alamos, New Mexico, and began working on the Manhattan Project. He remained with the project from 1943 until 1945 when he returned to Denmark and his institute.
Bohr was very concerned about the possible catastrophic effects of the nuclear warfare, and in 1950 he wrote an "Open Letter to the United Nations" in which he urged that the weapons be placed under international control. In 1955, Bohr was named Chairman of the Danish Atomic Energy Commission.
Bohr died on November 18, 1962, at his home at Carlsberg.
Bohr was a personable man who was well liked and well respected. He had a grand sense of humor and is quoted:
"Never express yourself more clearly than you can think."
"Prediction is very difficult, especially about the future."
"An expert is a person who has made all the mistakes that can be made in a very narrow field."
Awards and Honors
- 1922, Nobel Prize for Physics
- 1926, Fellow, Royal Society
