Niels Bohr
Or: Well, That's Clever

One of the greatest minds of the 20th Century, this Danish scientist's name--Niels Henrik David Bohr, in full--is listed among such other giants as Einstein, Fermi, Rutherford, and perhaps most controversially, Werner Heisenberg.

For those of us that aren't physicists, the finer details of Bohr's contributions to the understanding of physics and the universe go parading over our heads like so many free electrons; but his work was essential to the development of the atomic model, the beginnings of quantum theory, and the atom bomb--so much so, that he is often referred to as 'the Father of modern physics.'

And he had quite the life.


Niels was born of excellent stock, and had the sort of family in which being a genius wasn't a liability.

And from then on things move a little more rapidly.


Bohr attended Copenhagen University in his twenties--his father probably didn't need to help get him in--and soon distinguished himself from his peers with the guidance of Professor C. Christiansen, another physicist of renown.

Laboratory Work

Niels' studies became increasingly theoretical even before graduation, and it was his interest in theoretical physics that took him from Denmark to Engand.

Bohr got himself teaching appointments at both Copenhagen University and Victoria University in Manchester during World War I, and wrapped up the decade by becoming head of the Institute for Theoretical Physics-a school more or less established for him to run by the good people of Copenhagen U.

The Prize

After two more years of intense study and work in Copenhagen, Bohr delivered a lecture for which he was awarded the Nobel Prize in 1922.

Including research from papers he produced over the previous four years, Bohr spoke on the subjects of atomic stability and electrodynamic theory, giving accounts of quantum theory's origins, the hydrogen spectrum, and an explanation of the relationships between elements.

He summed up the ideas like this:

Notwithstanding the fundamental departure from the ideas of the classical theories of mechanics and electrodynamics involved in these postulates, it has been possible to trace a connection between the radiation emitted by the atom and the motion of the particles which exhibits a far-reaching analogy to that claimed by the classical ideas of the origin of radiation.

Well, obviously.

The Roaring Twenties

In addition to wild stock market speculation, antic dancing, and the raising of hem-lines, the 1920s produced some major scientific advances in the realm of theoretical physics.

By this time, Bohr's reputation was already well-made, and his stature in the science world made him the go-to guy for all things theoretical. Most new ideas were run by him for his opinion, which came to be taken as a sort of gospel.

Werner Heisenberg was by the first part of the decade already known to Bohr as a brilliant young mind, and the two soon became friends.

Quantum mechanics was a science on the make by 1925, and Bohr was in its top echelons. Heisenberg was also well on his way, and his 1927 declaration of the Uncertainty Principle really put him on the map--though of course, you couldn't tell how fast he was moving.

The two met in Italy to discuss the subject, and Bohr put forth this response: Complementarity.

Bear with me, here--I'm no scientist. For a more and better understanding, consult someone who got a decent education. Essentially, his theory amounted to an entirely new interpretation of the foundations of quantum theory, one he thought might be applied to schools beyond physics, from biology to psychology.

It came to be the accepted view despite widespread disagreements--even Einstein was shaking his head at it.

World War II

With the rapidly increasing understanding of nuclear principles, it wasn't long before fission became an area of developing interest, and once again Bohr was at the forefront-or would have been, if the Nazis had left him alone.

  • 1939: Bohr develops a full understanding of nuclear fission with the uranium isotope 235.

  • 1940: Timing is everything. The Nazis occupy the country, and put Bohr in an unfortunate position.

    Though christened in a church--and therefore a Christian as far as your average census taker would be concerned--Niels had Jewish origins on his mother's side, and the invading Germans liked people to have more than just a few generations of 'purity'.

  • 1941-1943: Accordingly, they start making things rough for him. Recognizing his value as a scientist, the Nazis permit Bohr to continue his studies, but severely restrict his contact with other physicists, many of which were old friends that had already skipped continental Europe for England or the United States.

    He was certainly being watched as a potential spy, and more likely than not had to step outside for a danish if we wanted to speak freely.

  • 1943: Bohr flees Denmark for Sweden, via fishing boat, then to England--supposedly with the complete works of Charles Dickens in tow, to help him learn english.

    There, he takes up with the other disenfranchised geniuses from Europe on the nuclear fission project, moving now at full steam toward making a bomb. They presume the Germans under Heisenberg are doing the same.

    The team eventually moves to Los Alamos, in New Mexico, to combine their efforts with the Americans already on the job.

  • 1944: Bohr has an up-front role in the science behind the bomb, but not in its manufacture--though his designs were instrumental to the development of the triggering mechanism.

    His relationship with Heisenberg had long gone south, and never recovered.

The nature of his relationship with Heisenberg, and what exactly transpired between the men during Heisenberg's immediately pre and post-occupation visits to him in Denmark are the subject of much intensely fascinating debate. The entire future of nuclear weapons, and thus the future's entire geopolitical landscape--lay in the hands and minds of these two physicists, each a friend, father, or son to the other.

Michael Frayn, in his play, Copenhagen, makes a dramatic study of these episodes in their lives. It's a brilliant piece of work, and very well worth a read.

As the Dust Settled

Bohr spent much of his time after the war working for international cooperation and control over the world's scary new toy, writing letters to presidents and prime ministers.

Things obviously didn't quite work out as he'd hoped, bomb-wise.

He also kept up his studies and research, meticulous to the very end, which came on November 18, 1962, following a heart attack in his home in Copenhagen. He was survived by his wife Margrethe and four of their six children; two died in their youth.

Important Details

The man was prolific--115 publications, doctor, honoris of thirty-four colleges and universities around the globe, president of the Royal Danish Academy of Sciences and the Danish Cancer Committee, and chairman of the Danish Atomic Energy Commission.

Several of these posts he kept until he died.

A year after his death, in 1963, Denmark issued a stamp with the Bohr atom on it, commemorating the 50th anniversary of his atomic theory.

For further studies on the man, bear these phrases in mind:

  • Liquid Droplet Theory

  • Complementarity

  • The Copenhagen Interpretation

That ought to be enough to start. For, as Bohr once said upon explaining quantum theory to a room full of philosophers:

Anyone who is not dizzy after his first acquaintance with the quantum of action has not understood a word.

Chunks of U-238 to:

Log in or register to write something here or to contact authors.