Who: Danish physicist
What: Developed the Bohr model of the atom, founded the Institute of Theoretical Physics and later helped refugees flee Nazism.
Where: Born and died in Copenhagen.
Why: After Albert Einstein, one of the most famous physicists in history.
When: October 7 1885 – November 18 1962.
“Never express yourself more clearly than you are able to think” – Niels Bohr.
Niels Bohr was, to all intents and purposes, a scientific badass. His Bohr model of the atom formulated the idea that electrons move in separate orbits around the nucleus, and that the number of electrons determines the properties of an element. He later contributed significantly to the field of nuclear fission, with his liquid droplet theory being instrumental in the early attempts to split uranium in the 1930s, which led to the atomic bomb, despite Bohr’s advocacy for peaceful atomic physics. Between 1933 and 1962 he developed the idea that an electron could be viewed as either a particle or a wave, but never both simultaneously, contributing to the field of quantum mechanics when it was in its infancy. He was awarded the Nobel Prize for Physics in 1922. When the Nazis invaded his homeland of Denmark in 1940, he had Max von Laue and James Franck’s Nobel medals dissolved in agua regia, where they were safely stored and restruck after the war. With help from the Danish resistance, he fled to Sweden in September 1943, persuading King Gustaf V to provide willing asylum to Jewish refugees, and escaped to Britain on October 6 1943, where he was provided with an apartment and worked on the Tube Alloys project, Britain’s nuclear development program. Some of his other scientific accomplishments include predicting the element hafnium, BKS theory and the Bohr-Sommerfeld quantization. After the war, he returned to Copenhagen, where he lived out the rest of his days, dying of heart failure in November 1962.