Carolyn and I have appreciated the work of Danish physicist and philosopher Niels Bohr, who made foundational contributions to understanding atomic structure and quantum theory. He received the Nobel Prize in Physics in 1922. He was also one of the first to consider and explore “quantum metaphysics,” the notion that matter is derived from consciousness.

Niels Henrik David Bohr was born in Copenhagen, Denmark in 1885. He was the second of three children. His father was a professor of physiology, and his mother came from a wealthy Jewish banking family.

When he was seven, Bohr started his education at Gammelholm Latin School. In 1903, he enrolled at Copenhagen University, where he studied physics, astronomy, mathematics, and philosophy. In 1905, Bohr won a gold medal competition for a physics contest measuring the surface tension of liquids, that he had to make his specialized glassware for. He later submitted an improved version of this paper, which was published by the Royal Society of London.

In 1909, Bohr received his master’s degree in mathematics, and in 1911 he received his doctorate in physics from Copenhagen University for his research into the magnetic properties of metals. During this time Bohr also met and married Margrethe Norlund, a Danish woman who collaborated with him on his research and helped to edit and transcribe his work.

In 1911, Bohr traveled to England, where most of the theoretical work on the structure of atoms and molecules was being done. He studied electromagnetism and researched cathode rays. In 1912, he began teaching physics to medical students at the University of Copenhagen, and in 1913 he did revolutionary work on creating a new model of the atom that became known as the “Bohr model” of the atom, which is the most basic particle of the chemical elements. This model of the atom consists of a small, dense nucleus surrounded by orbiting subatomic particles called “electrons,” in a way that is analogous to the structure of the solar system.

Bohr advanced atomic theory by proposing that electrons travel in orbits around the nucleus, or center of the atom, in “stationary states” that stabilize the atom. Bohr also introduced the idea that an electron could drop from a higher-energy orbit to a lower one, and in this process emit a “quantum” of discrete energy.

A quantum is the minimum amount of energy in any physical interaction between the fundamental forces of nature. Bohr’s theory became a basis for what is now known as the “old quantum theory”—which predates modern quantum mechanics. This was considered a breakthrough by many physicists of his day, including Albert Einstein.

In 1916, Bohr was appointed as the Chair of Theoretical Physics at the University of Copenhagen, a position that was created especially for him. In 1918, he established an Institute of Theoretical Physics at the university, where he became the director, and this institute is today known as the Niels Bohr Institute. Bohr was extremely dedicated to this work, and he and his family moved into an apartment on the first floor. Bohr’s institute served as a focal point for researchers into quantum mechanics during the 1920s and 1930s, when most of the world’s best-known theoretical physicists spent time there.

In 1919, Bohr revised his model of the atom, and its relationship with electrons, and in 1921, he published a paper that showed that the chemical properties of each element were largely determined by the number of electrons in the outer orbits of its atoms. In 1922, Bohr was awarded the Nobel Prize in Physics “for his services in the investigation of the structure of atoms and the radiation emanating from them.”

In 1924, physicist Werner Heisenberg — who developed the mathematical foundations of quantum mechanics, and a fundamental concept in quantum mechanics known as the “uncertainty principle”— came to the University of Copenhagen, where he worked as an assistant to Bohr from 1926 to 1927, and they had an important influence on one another. Around this time, Bohr became convinced that light behaved like both waves and particles, and he conceived the philosophical principle of “complementarity,” which proposed that physical structures could have, what appear to be, mutually exclusive properties — such as being a wave or a stream of particles, depending on the experimental framework, or one’s perspective.

Heisenberg said that Bohr was “primarily a philosopher, not a physicist.” Bohr was influenced by Soren Kierkegaard’s philosophy, and he had an interest in metaphysics and psychic phenomena. In 1932, Bohr met with psychiatrist Carl Jung at a conference on intellectual cooperation, and they discussed the concept of synchronicity— the simultaneous occurrence of events that appear significantly related but have no discernible causal connection. Bohr was also interested in the concept of psychokinesis — the influencing of matter by thought — and he believed that parapsychology was worthy of study. Bohr was also one of the first to consider and explore the concept of “quantum metaphysics,” the notion that matter is derived from consciousness.

In 1940, early in the Second World War, Nazi Germany invaded and occupied Denmark. In 1943, word reached Bohr that the Nazis considered him to be Jewish since his mother was Jewish and that he was therefore in danger of being arrested. The Danish resistance helped Bohr and his wife escape to Sweden.

In 1943, Bohr arrived in Washington, D.C., where he met with the director of the Manhattan Project, the research program that led to the development of the atomic bomb. Bohr visited Einstein at the Institute for Advanced Study in Princeton, New Jersey, and went to Los Alamos in New Mexico, where the atomic bomb was being designed.

Bohr did not remain at Los Alamos, but he paid a series of extended visits there over the next two years. Physicist Robert Oppenheimer credited Bohr with acting “as a scientific father figure to the younger men” that were there, and Oppenheimer gave Bohr credit for an important contribution to the work on an essential part of the project called “modulated neutron initiators.” “This device remained a stubborn puzzle,” Oppenheimer said, “but in early February 1945 Niels Bohr clarified what had to be done.”

Following the end of the war in 1945, Bohr returned to Copenhagen, where he was elected as president of the Royal Danish Academy of Science. In 1947, the king of Denmark, Frederik IX, awarded Bohr with membership in the Order of the Elephant — a Danish order of chivalry and is Denmark’s highest-ranked honor — which was normally only awarded to royalty and heads of state. Bohr designed his coat of arms, which included a Chinese yin-yang symbol in its center, signifying that “opposites are complementary.” Bohr also received numerous other awards and honors, such as the Matteucci Medal, the Copley Medal, and the Atoms for Peace Award.

In 1962, Bohr died of heart failure at his home in Carlsberg, Denmark.

In 1963, the Bohr model’s semi-centennial was commemorated in Denmark with a postage stamp depicting Bohr, the hydrogen atom, and the formula for the difference in hydrogen energy levels. Several other countries have also issued postage stamps depicting Bohr. In 1997, the Danish National Bank began circulating the 500-krone banknote with a portrait of Bohr smoking a pipe. Additionally, an asteroid, 3948 Bohr, was named after him, as was the Bohr Lunar Crater, and Bohrium, the chemical element with atomic number 107.

Some of the quotes that Niels Bohr is known for include:

Everything we call real is made of things that cannot be regarded as real. If quantum mechanics hasn’t profoundly shocked you, you haven’t understood it yet.

An expert is a person who has made all the mistakes that can be made in a very narrow field.

The opposite of a correct statement is a false statement. But the opposite of a profound truth may well be another profound truth.

No, no, you’re not thinking; you’re just being logical.

There are some things so serious that you have to laugh at them.

A physicist is just an atom’s way of looking at itself.

The meaning of life consists in the fact that it makes no sense to say that life has no meaning.

We must be clear that when it comes to atoms, language can be used only as in poetry. The poet, too, is not nearly so concerned with describing facts as with creating images and establishing mental connections.

Every sentence I utter must be understood not as an affirmation, but as a question.

Your theory is crazy, but it’s not crazy enough to be true.

by David Jay Brown