Thanks to him, we understood the structure of the atom: Who is Niels Bohr?

(1885-1962) Danish physicist. The model of the atom, which he arrived at by explaining the hydrogen spectrum, formed the basis of modern atomic physics. Niels Henrik David Bohr was born on 7 October 1885 in Copenhagen. His father, Christian Bohr, was a professor of physiology at the University of Copenhagen, and his mother was the daughter of one of Denmark's leading bankers. After studying physics and philosophy at the University of Copenhagen, Niels Bohr, who received his doctorate in 1911 with his thesis on the electron theory of metals, went to England in the same year and started to work with J J Thomson at Cambridge University. When he went to Manchester University in March 1912 to continue his research with Rutherford, the subject that attracted him the most was the atomic model that Rutherford had proposed a year earlier. Though his work in Rutherford's lab only lasted a few months, it proved fruitful enough to make Bohr's design a reality. Talking about that period later. He would say that as soon as he saw Kydberg's work on the hydrogen spectrum, and especially Balmer's formula, everything suddenly became clear in his mind. It was enough to see Balmer's formula to realize that different laws apply to the interaction of the atom with light than in classical physics. Bohr was no longer working in Rutherford's laboratory when he succeeded in transforming this revolutionary design in physics into a permanent and valid atomic model.

Returning to his country in the summer of 1912 and marrying Margrethe Norlund, Niels Bohr began working as an adjunct professor at the University of Copenhagen at the beginning of that school year. He also compiled a long review of his work in Manchester. When his historical article "On the Constitution of Atoms and Molecules" was published in three parts in the June, September, and November 1913 issues of Philosophical Magazine, some physicists admired this interpretation, which combines classical mechanics with quantum theory, while some physicists praised it. part with skepticism.

Niels Bohr, who had been at the University of Copenhagen until 1914, began to feel distressed about not being able to devote enough time to his research and received a call from Rutherford to teach at the University of Manchester. Knowing that he could not find a more favorable environment to continue his studies, Niels Bohr immediately accepted and went to England in the autumn of 1914 and worked in the Department of Theoretical Physics at the University of Manchester until 1916. During these two years with Rutherford, he began to think that a private institute was needed so that atomic and nuclear physics could embark on an effective path of development on solid foundations. In 1916, when he received a professorship call from the University of Copenhagen and returned to his country, he proposed this proposal to the University. This idea, which was received very positively, was taken up as soon as the war was over. The city of Copenhagen donated a large space to the institute, and Bohr became the first director of the Institute for Theoretical Physics at the University of Copenhagen. Increasing its effectiveness with the participation of physicists from all over the world, the institute soon became the largest center of theoretical physics under the name "Copenhagen School" and Bohr continued to be the director of this institution until the end of his life.

The Hughes medal, awarded by the Royal Society in London in 1921, was the first award for Bohr's scientific work, followed by the Nobel Prize in Physics in 1922. However, the most valuable praise for him was seeing the adoption of the institute and the flocking of young physicists such as Hevesy, Pauli, Heisenberg, and Dirac to work with him. Indeed, there is hardly any major phase of theoretical physics in the 1920s that was not connected in one way or another with the Copenhagen School. Heisenberg's matrix mechanics, Schrodinger's wave mechanics, Born, Dirac, and Jordan's proofs of the equivalence of these two mechanics, Pauli's electron spin theory, Louis de Broglie's theory of matter and wave dilemmas are all from the lively discussion at Bohr's institute. settled in physics. This is the golden age of quantum physics when a generation of physicists from various countries who came to the Copenhagen School made a coherent generalization of quantum mechanics and electromagnetism in unmatched collaboration.

Apart from being the director of the Institute of Theoretical Physics, Niels Bohr, who was the chairman of the Danish Royal Academy of Sciences and the Danish Atomic Energy Commission from 1938 until his death, directed the first phase of the program for the peaceful use of atomic energy in this commission, and especially after 1939, humanity and peace. The effort he gave to his name had a more important place in his life than his scientific studies.

In 1940, Niels Bohr, who pushed laboratory research into the background in German-occupied Denmark, defended the right to life of Danish Jews and opposed the use of science for mass destruction, fled to Sweden with his family in September 1943 with the help of the Danish resistance organization. From there he went to England and then to the USA. In those years, England and the USA, who knew that Germany was preparing to make an atomic bomb and that they could not prevent the spread of Germany to the whole world unless the Allies had such a weapon in their hands, also started to work on atomic bombs. In 1944, the first warning, emphasizing the great danger that atomic weapons would pose to humanity, came from Bohr, who participated in these studies in both countries and played an active role in the first phase of the Manhattan Project in Los Alamos laboratories in the USA.

On July 3, 1944, he sent a letter to Roosevelt and Churchill, suggesting that the war was now coming to an end and that atomic weapons and atomic energy should be brought under international control in order to prevent the nuclear arms race that may arise after the war. When this attempt failed, he applied to the United Nations in a letter in 1950, calling for "an open world in which each country can assert its existence only by contributing to the common culture and by offering its own experience and resources to other countries". The "First International Conference for the Peaceful Use of Atomic Energy", which convened in Geneva in July 1955 and brought together almost all the world's nuclear physicists after a break of more than fifteen years, was the first product of Bohr's efforts. In 1957, the US "Atoms for Peace" Prize was awarded to Bohr for the first time. One of Bohr's important activities in those years was the development of CERN (Conseil European pour la Recherche Nucleaire/European Nuclear Research Council), which was established near Geneva in 1952. After working for five years at Bohr's institute in Copenhagen and under his supervision, the organization's theoretical research division was moved to Geneva in 1957 and merged with the experimental research division. It was also Niels Bohr who established and organized NORDITA ("Northern Countries Institute for Theoretical Atomic Physics"), affiliated to the Institute for Theoretical Physics in Copenhagen, in order to train young theoretical physicists and direct nuclear physics research in Scandinavian countries. Returning to his country at the end of the 1st World War and continuing his research and his duty at the Danish Royal Academy of Sciences, Bohr died in Copenhagen on 18 November 1962. With his personality always open to new ideas and developments, he greatly influenced the generation of young physicists who grew up after him and led many of them in the development of quantum physics.

His brother, Harald August Bohr (1887-1951), was also a professor of mathematics at the Copenhagen Polytechnic Institute and at the University of Copenhagen.