How come the famous Nobel Prize was awarded to a football player?

“I was able to achieve some of my success (and win this year’s Nobel Prize in Physics) because of your groundbreaking contributions. So it is a great blessing that you won the Nobel Prize before me.”

One day in November 1922, in an office on the third floor of the Institute of Theoretical Physics at the University of Copenhagen, Denmark, Niels Henrik David Bohr, a member of the Royal Danish Academy of Sciences and the head of the Copenhagen School, put down his coffee, took out his fountain pen, filled it with ink, spread out the letter paper, solemnly wrote this text, and then asked his assistant to send it urgently to Einstein who was far away in Japan.

Since they met two years ago, they have been exchanging sharp words and endless debates, but they have also respected and appreciated each other. They have been both enemies and friends, and their story has become a legend in the scientific world.

When Bohr learned that he was nominated by the Nobel Prize Committee, he felt uneasy because he felt that although he, Planck and Einstein had all made contributions to quantum theory, Einstein combined their research and should have won the prize before him.

Fortunately, the Nobel Prize Committee announced at the same time that Einstein and Bohr won the Nobel Prize in Physics in 1921 and 1922 respectively. Feeling relieved, he wrote the above short message to Einstein.

Bohr and Einstein at the Solvay Conference Source: Global World Network

In fact, the "some achievements" in Bohr's text message were purely modest. He liked playing football and followed the steps of his predecessors in studying quantum mechanics. He proposed the theory of the atomic structure model of electron energy levels and solved the problem of the stability of atomic structure, marking the completion of the construction of the modern physics building. He is therefore called the "godfather" of quantum physics.

01

Physics on the football field

In the summer of 1903, the 18-year-old Bohr was admitted to the Department of Natural Sciences at the University of Copenhagen in Denmark with excellent grades, majoring in physics.

He has two major hobbies: one is to study physics. It is said that he completed the physics courses for the first half of his junior year by self-study when he was a freshman; the other is to like playing football. Less than half a year after entering school, he became the goalkeeper of the school football club.

During football matches, he often brought a few pieces of chalk: when the ball was in the opponent's half, he would use the chalk to calculate physics formulas on the goal frame; when the ball entered his own half, he would immediately throw away the chalk and defend the goal. When he was about to graduate from university, he was selected for the national football team and participated in many games.

A few years later, Bohr devoted himself to the field of atomic physics research, using playing football as a break or a change of pace from work. He also took time to participate in national team training or competitions, becoming a famous "scientist star" in the scientific community.

Young physicist Bohr Image source: Physics Bimonthly Network

In his senior year, Bohr made a name for himself at the university. With a paper on the surface tension of liquids, he won the gold medal from the Danish Academy of Sciences. This paper later became an important clue in the study of atomic physics.

In 1911, Bohr, who had obtained his doctorate, went to England for further studies. He first studied at the Cavendish Laboratory headed by Thomson at Cambridge University, and six months later he went to Manchester to join the research team of physics giant Ernest Rutherford, becoming Rutherford's favorite student.

Bohr respected his mentor so much that he named his youngest son Ernest Bohr (Chinese and Western cultures are different, and Chinese people are very averse to having the same name as their predecessors).

Bohr was very interested in the planetary model of atomic structure proposed by Rutherford. At that time, many scientists were devoted to the study of atomic structure, among which Rutherford's planetary model was the most popular.

This theory holds that the interior of an atom is like a solar system, the nucleus is like the sun, and the electrons are like planets, which constantly revolve around the nucleus and the orbits of the electrons will change.

The evolution of the atomic model. Image source: Physics Bimonthly Network

There is an obvious problem with this theory. According to known theories, after electrons radiate electromagnetic radiation, their orbits will become smaller due to energy loss and eventually collapse into the nucleus rather than continuing to revolve around the nucleus.

Where did the problem lie? Bohr decided to find a reasonable explanation for his mentor's theory.

02

New theory on "February transformation"

It is not easy to find a reasonable explanation. Experiments are definitely not an option. The atomic structure is too microscopic to be observed, so it is difficult to conduct experiments. The best way is to first establish a reasonable theory and then use physical formulas to verify the theory.

Theoretical research requires the selection of appropriate substances, and hydrogen has the simplest structure of all substances. "Let's study the structure of hydrogen atoms or hydrogen-like atoms." With this in mind, Bohr devoted himself to a new round of research.

In 1912, although Bohr returned to Copenhagen, Denmark, and devoted himself to studying the structure of the hydrogen atom, there was little progress.

In February of the following year, when his colleague Hansen came to visit him and mentioned the mathematician Balmer's empirical formula for the wavelength of spectral lines, Bohr suddenly had an idea: since the planets revolve around the sun in fixed orbits due to universal gravitation, wouldn't electrons also revolve around the nucleus in specific orbits due to special forces?

To prove this point, one only needs to list something like Balmer's empirical formula and then import the data for calculation. Finding the research direction through accidental conversation and quickly achieving results is the "February transformation" in Bohr's life.

Mathematician Balmer Source: Physics World Network

Soon, Bohr proposed a completely new atomic structure theory: the electrons in the hydrogen nucleus usually rotate along orbits of specific distances without releasing electromagnetic waves. These orbits are called energy levels. When the electrons jump between energy levels, they release electromagnetic waves and eventually collapse into the original electron nucleus due to energy loss. In order to facilitate formula calculations, he boldly "quantized" these energy levels.

Soon, he listed the energy level formula and orbital radius formula using the hydrogen atom as an example (see figure).

After countless precise calculations, Bohr determined that the atomic structure he proposed was reasonable.

From July to September 1913, at the recommendation of Rutherford, Bohr's long paper on the atomic model, "On the Structure of Atoms and Molecules", was published in three issues in the "Philosophical Magazine" of the Royal Society of London. The paper successfully explained the structure and properties of the hydrogen atom, and formally proposed the electron energy level atomic model (later called the "Bohr model").

This paper is the famous Bohr model "trilogy".

The Bohr model is a milestone in the development of quantum theory. Previously, Planck and Einstein used the concept of quantization to explain blackbody radiation, and Rutherford's planetary model was just an inference of the atomic structure without any explanation.

The Bohr model made people further realize the tremendous power of quantum, and quantum theory therefore entered a stage of vigorous development.

03

The whole country celebrates winning the grand prize

After Bohr completed that important paper on the atomic structure model, his fame grew and he was hired as a professor by the University of Manchester, the University of Copenhagen and other institutions. He was elected as a member of the Royal Danish Academy of Sciences in 1917.

He was never idle. In September 1920, he planned to build the Copenhagen Institute for Theoretical Physics (later known as the "Bohr Institute") in Denmark.

The institute mainly studied quantum mechanics at the time, and attracted outstanding physicists such as Heisenberg, Pauli, Landau, and Herwig. In the academic atmosphere of freedom and equality, the Copenhagen School was born, which had an important impact on the physics community.

Copenhagen Institute for Theoretical Physics Source: Physics World

In view of Bohr's important contributions to atomic models, quantum theory research and the promotion of physics, the Nobel Prize Committee decided to award him the 1922 Nobel Prize in Physics.

When the news reached Denmark, people all over the country were shocked: it turns out that our country not only produces beef and wheat, but also produces great scientists who have won the Nobel Prize.

In the office, colleagues prepared cakes and champagne for Bohr, and some even played cheerful violin music; on the way home, everyone greeted him, and the old man at the roadside ice cream shop even gave him free hot drinks; when he opened the door, his children gave him warm kisses, and his wife prepared a table of delicious food...

In the following days, telegrams of congratulations from all over the country flew in, including sincere blessings from his mentor Rutherford. Bohr's love of playing football was brought up again, and Danish newspapers and media generally used the following headline: "Nobel Prize awarded to famous football player Niels Bohr".

Image source of the report on Bohr's award: Physics Bimonthly Network

In the face of honor, Bohr still kept a clear head.

After he wrote a letter to Einstein saying that the other party should win the Nobel Prize before him, he went alone to Stockholm, Sweden to attend the Nobel Prize ceremony.

He gave a wonderful keynote speech at the conference. At the end of the speech, he announced a good news: element 72 on the periodic table has been officially confirmed. At that time, many scientists tried to find this element, but to no avail.

This is Bohr's best gift to the Nobel Prize Committee and the physics community!

END

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Editor/Xiao Xitushuo