This essay is about Niels Bohr, so let's take ourselves to the small low-lying country of Denmark -- specifically, its capital, Copenhagen -- on the east coast, facing and close to Sweden.
There sits one of the oldest institutions of learning in Scandinavia -- the University of Copenhagen, with such illustrious alumni as the astronomers Ole Roemer, measurer of the speed of light and Tycho Brahe.
Views across the city are of the spires of churches, and it was in Copenhagen in 1885 that Nobel prize winner Niels Bohr was born and grew up.
A star soccer player, like his younger brother Harald Bohr, who played for Denmark in the 1908 Olympics -- Niels Bohr earned his Ph.D. in 1911. Then, at 26, he was, like many young graduates today, anxious to travel. His thesis had been about electrons in metals, and, funded by Carlsberg beers, he went to Cambridge, England, to continue his studies with the great JJ Thomson, discoverer of the electron.
Niels Bohr, now a foreign student, had studied English at school, and he and his brother loved reading together. One of their favorite books was David Copperfield.
After he had located the Cavendish Lab and introduced himself to JJ, carrying his own thesis on electrons as well as a copy of one of JJ's papers, he wrote excitedly to his fiancee Margrethe back in Copenhagen "... JJ was extremely kind. I believe he thought there was some sense in what I said ..." [ref.1, p.33].
Soon after Christmas in Cambridge, Ernest Rutherford visited from Manchester [ibid,p.35-36] to give a talk. A big friendly New Zealander, Rutherford had recently discovered that atoms have nuclei -- a fact that is well-known today of course -- from his experiments of firing positive alpha particles from radium into thin sheets of materials, and finding that while most went straight through, a few occasionally bounced right back. This meant that there was a tiny concentrated positive nucleus in the atom. Within a few weeks Bohr had decided that his interests lay firmly on the actual structure of atoms, so Bohr completed his Cambridge tasks and asked Rutherford if he could join him in Manchester, spending the next year working out how atoms actually radiate.
By 1913 Bohr had developed the model of the atom that is accepted today -- the Bohr atom -- and for which he was awarded the 1922 Nobel Prize in physics, a year after Einstein's. He returned and married Margarethe. They had 6 sons and he founded Copenhagen's Institute for Theoretical Physics, spending most of the rest of his life there.
We now fast-forward to WW2. In 1943 the Nazis appropriated Denmark, and ordered the deportation of all Danish Jews. The tiny country knew it could not defend itself against the German military. Niels Bohr, a 'catch' amongst the world's atomic scientists, and who was half Jewish from his mother's side, knew he would have to escape. With the Gestapo patrolling the streets, in winter darkness he was taken by members of the Danish resistance to meet a little boat which would carry him to a bigger fishing boat and thus across the Kattegat to Sweden. Later, an unarmed British bomber was sent on Churchill's orders from UK to Stockholm, and 58 yr old Niels Bohr, wrapped in a flying suit with a parachute and flares strapped to his back, was placed in the bomb bay [ref.1, pp 306-310] -- the flares being in case, under attack by German fighters, he had to drop into the North Sea. Because the bomber could fly higher than the German fighter planes, Bohr lost consciousness over Norway but fortunately regained it when they came lower. The plane landed safely in Scotland.
He was put on a ship to America, under the assumed name Nicholas Baker, ultimately reaching all the other atomic scientists in Los Alamos, many of whom, such as Fermi and Oppenheimer, he had worked with between the wars. The rest is history, with the success of the Manhattan Project and the end of the war in 1945.
Bohr, lover of skiing, fixing things and cutting firewood, died of a brain hemorrhage in 1962, at the age of 77.
References:
1. "Niels Bohr", by Ruth Moore; Alfred A Knopf, NY (1966.)
2. "Niels Bohr", edited by S Rozental; 1967, John Wiley & Sons, NY.
Dr. David Nightingale is Professor Emeritus of Physics at the State University of New York at NewPaltz and is the co-author of the text, A Short Course in General Relativity.
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