1900: A physics genius wandering around Europe

Chapter 270 The flaws of the planetary model! Difficulties of Bohr's theory!
On the evening of December 1910, 12, Copenhagen, Denmark.

Just as the physics community was going crazy about the second Bruce Conference, Bohr had already returned safely to his hometown.

Living in a luxurious suburban manor of several thousand square meters, Bohr's parents prepared a sumptuous Christmas dinner.

The beautiful maid kept shuttling back and forth, allowing Bohr to get everything without having to do anything.

But Bohr was not in a good mood. He just ate casually, obviously he was worried.

Father Christian probably knew what his son was thinking, so he smiled and said, "Bohr, only when you have a full meal can you have the energy to think."

"As a professor of physiology, I cannot study the world as well as you do; but I am definitely more in-depth in studying people than you are."

“No matter how great a physicist is, he cannot figure out a difficult physics problem if he is hungry.”

Bohr smiled knowingly and said, "Thank you, father."

"I've just been a little stressed lately."

"It's okay, don't worry about me."

Christine asked, "Oh? Did Professor Bruce give you a difficult question?"

"Your King's College has been frequently mentioned in newspapers recently."

"I even see your name a lot."

"Perhaps this is causing you trouble?"

Bohr did not say anything after hearing this, but ate quietly.

I was thinking about my study experience over the past year and a half.

Among Professor Bruce's seven doctoral students, I am undoubtedly the one he values ​​the most.

Even Mr. Qian Wushi and other Chinese compatriots of his mentor cannot compare to him.

Not only did his mentor make him the recorder for the first blues conference, but he also took him on his trip to the United States.

These two opportunities are what countless people dream of.

However, you can get it easily.

In the laboratory, everyone knew that he was Professor Bruce's direct disciple, and Bohr was often asked to preside over any departmental meetings.

Everyone thinks this arrangement is reasonable.

Because Bohr was indeed the smartest student, he had a very flexible mind and could often come up with very advanced ideas.

Take Soddy's explanation of the periodic table, for example.

Everyone in the department knew that Bohr had talked about related topics before.

However, since his topic was atomic structure, he did not spend energy to conduct in-depth research.

Regret a huge achievement.

But Bohr didn't care.

However, with the rise of the younger generation such as Qian Wushi and young Prague, Bohr felt a little pressure.

Although I am jokingly called "the smartest doctoral student" by everyone, physics is about results.

No matter how smart you are, it’s useless if you don’t have a decent paper to present.

As for ordinary papers like those published in Nature journals, Bohr never considered them.

It’s useless even if you publish 100 articles.

Just like my mentor, Professor Bruce, who has only published less than ten academic papers in the past ten years.

But each article suppressed the entire physics community.

All the papers in all the journals in the world combined might not be as valuable as those ten papers.

This is the realm that Bohr pursued.

He has always regarded Professor Bruce as his idol and ultimate goal.

If you want to wear a crown, you must bear its weight.

One can imagine the pressure Bohr was under.

However, he still smiled and said to Christine: "Dad, I am 25 years old and can handle anything on my own."

Christine patted her son on the shoulder, feeling very happy and proud.

My son must be doing something very, very difficult, otherwise with his intelligence, he would have solved it long ago.

Therefore, Christine was very grateful to Li Qiwei, who really put in a lot of effort and tried his best to cultivate Bohr.

He decided to find some time to visit and thank Li Qiwei.

Bohr's mother lovingly handed Bohr all his favorite foods.

Soon after Bohr finished his meal, he went upstairs to his room, lay on the bed and quietly thought about his topic.

The doctoral thesis that Ridgway gave Bohr was the study of the planetary model of atomic structure.

This is the most important research direction in the current physics community.

Atomic research!

As predicted by the first Bruce Conference, modern physics will revolve around atoms.

Planetary models are at the core of atomic research.

This shows that Ridgway loved Bohr very much, which was also the reason why Bohr was under great pressure.

The tutor reserved for himself the best, most cutting-edge and most likely to produce results topic in physics.

However, the tutor himself went to study the incredibly difficult theory of general relativity.

Bohr was extremely grateful.

The planetary model is simple.

The nucleus is located in the center of the atom, and the electrons move in circles around the nucleus.

By analogy with the solar system, the nucleus is the sun, and the electrons are planets like the earth.

However, this model has two problems that cannot be explained, or two defects.

First, the planetary model is unstable.

According to Maxwell's electromagnetic theory, when electrons move in a circular motion around the nucleus, they release electromagnetic radiation (i.e. radiation energy), which causes the electrons to fall into the nucleus.

However, all current experiments have not observed this phenomenon.

This shows that the movement of electrons is stable, but the planetary model cannot explain it.

Second, in his planetary model, Ridgway did not explain how electrons are arranged outside the nucleus.

Are electrons like in the solar system, with each electron occupying an orbit; or are they distributed randomly and in a disorderly manner?

Planetary models do not explain these and cannot account for them.

Of course, when Ridgway published his planetary model, Soddy's improved periodic table had not yet been published.

But until now, Soddy had not explained how the electrons were arranged.

As for the second question, Bohr had no idea at all.

But Bohr already had an idea for the first question.

(In real history, Bohr solved the first problem first and the second problem ten years later.)
Bohr's thinking was complex.

The falling of electrons into the nucleus is an inevitable result of classical mechanics and classical electromagnetism.

As long as people believe that classical physics is still correct at the atomic scale, the atomic structure will inevitably collapse.

The planetary model was proposed by Ridgway, who was Bohr's mentor.

Bohr had to choose between classical physics and his mentor.

Either classical physics is wrong, or your mentor is wrong.

But Bohr's respect for Ridgway came from the bottom of his heart.

Unless it is absolutely necessary, he would never think that his mentor was wrong.

But classical physics cannot be easily denied.

Bohr thought again of Ridgway's teachings and what he saw during his trip to the United States.

Classical physics is not outdated! It should not be abandoned!

There are still too many secrets waiting to be discovered! Therefore, Bohr made a bold guess.

There is nothing wrong with classical physics and the mentor’s theory!
It's just that a bridge is needed between the two.

And the bridge is Bruce's mentor's concept of quantum.

Bohr believed that classical physics was only applicable at the microscopic scale and some of its conclusions were not applicable.

But he still retained the concept of "orbit" in classical mechanics.

Bohr believed that in order to explain why atoms do not collapse, it is necessary to assume that electrons will not emit electromagnetic radiation as long as they are in certain specific orbits.

He called these specific orbits the "stable state orbits" of electrons.

Bohr believed that the orbits of electrons outside the nucleus could not move in arbitrary orbits as in classical physics.

Electrons have their own stable orbits, and they are discontinuous, which is called the quantization of electron orbits.

Let me give you a vivid example.

The Earth in the solar system revolves around the Sun. From the perspective of classical physics, the distance from the Earth to the Sun can be any value.

But according to Bohr's theory, the Earth can only stay in its current orbit and cannot exist in any other orbit.

This is a bit surprising.

This is Bohr's stable orbit hypothesis.

He absorbed the orbital concept of classical physics and the planetary model concept of his mentor Bruce, and finally integrated them together using quantum concepts.

In real history, this is why it is called old quantum theory.

Because Bohr respected his teachers so much, whether it was Rutherford or Ridgway.

So Bohr did not dare to be too bold and only took half a step. He retained the concept of orbit.

Later, quantum mechanics proved that the movement of electrons has nothing to do with the orbits of classical physics.

No matter what, Bohr is a connecting figure in quantum mechanics.

Without his old quantum theory, there would be no later quantum mechanics.

But this is why Bohr was depressed now. His hypothesis of stable orbit made no sense and was unconvincing.

Someone asked: Bohr, why do electrons have so-called stable orbits?
Bohr replied: Because electrons do not radiate energy in these orbits.

Others then asked: Why don’t electrons radiate energy in these orbits?
Bohr replied: Because the electron is in a stable orbit.

Others: ×&%￥#@.

This was an unsolvable circular argument, and Bohr knew it was unconvincing.

Of course, Bohr could also say arrogantly: Don’t ask why, just accept it, believe it or not.

This is how late quantum mechanics is. Don’t ask me, because even if you ask me I don’t know.

But Bohr is not stupid enough to be so reckless. He is still little Karami and he should be humble and low-key.

If it were Professor Bruce, he might be so bold.

So, Bohr now urgently needed evidence that could explain why the electron's orbit was not continuous and why it had its own specific stable state orbit.

Furthermore, he also needs to explain the radius of the stable orbit and the energy of the electron in the orbit. (These are all concepts of classical physics.)
Bohr did not expect this evidence to be authoritative, even if it was slightly relevant.

After all, when Professor Bruce published quantum theory, there was no evidence, and it could only explain the problem of blackbody radiation.

But now, he needs such a condition.

This is the difficult problem that Bohr has been thinking about recently, and it is also the crux of his loss of appetite.

After thinking about it, Bohr still had no clue.

So he simply picked up a Bohr notebook and decided to empty his mind.

But obviously, he couldn't concentrate.

Just when Bohr was feeling upset, there was a knock on the bedroom door.

He asked, "Who is it?"

A clear female voice replied: "Bohr, it's me."

Wow!
Bohr threw down his notes, got out of bed immediately, opened the door at a rapid speed, and said in surprise: "Margaret, why are you here?"

Margaret was Bohr's girlfriend, and the two were almost engaged.

Her father and Bohr's father were good friends.

But he is not a professor, but a businessman.

Margaret was tall, wearing a beautiful dress and makeup, and it was obvious that she had been dressed up carefully.

Moreover, she had a gentle personality and was deeply loved by Bohr.

As Margaret was pulled into the room by Bohr, she smiled and said, "My father and I are here to visit my uncle and aunt today."

"Christine said you were upstairs, so I wanted to come and see you."

"How are you doing in England?"

“There’s nothing good to eat there.”

Bohr instantly revived after seeing his girlfriend. He asked Margaret to sit on the bed and told her about his experiences over the past year.

During the conversation, some funny things were mentioned, which made Margaret laugh.

However, when Bohr talked about his research topic, he sighed again.

Margaret said, "Christine just told me that you've been under a lot of pressure lately and asked me to give you some advice."

"Is it because of your mentor, Professor Bruce?"

"A great scientist like him shouldn't embarrass you."

Bohr smiled and said, "My mentor loves me so much, how could he possibly embarrass me?"

"It's my own problem."

Margaret knew that Bohr was studying physics and she could not help much, so she changed the subject and joked:

"My father is still thinking about it and wants to meet Professor Bruce?"

Bohr was stunned and said with a smile: "Oh? Why does uncle want to meet my mentor?"

Margaret said: "Recently, my factory encountered a process problem, which seems to be related to physics."

"My father has consulted several people but they can't solve it."

"He thought a great scientist like Professor Bruce could certainly do it."

Bohr laughed and said, "Haha, it won't be easy to get my mentor to come forward."

"You know, in addition to his academic achievements, his achievements in technology companies are no less."

"I even suspect that my mentor will become the richest man in the world in the future."

"Ah?" Margaret's mouth opened into an O shape in shock, which made Bohr feel hot inside and his mouth dry.

However, he did not dare to act rashly, as they were both devout people and had already made an agreement.

“That’s amazing.”

"Bohr, you will definitely be as good as Professor Bruce in the future."

Bohr smiled bitterly and said, "Alas, the gap between me and my mentor is too big. I am afraid I will never catch up with him in my lifetime."

“I haven’t even got a clue about my thesis yet.”

Margaret felt distressed to see her future husband under so much pressure.

So, after a few seconds of mental struggle, she decided to comfort the other person.

"Bohr, how about I help you relieve some of the pressure?"

"You're hurting your body."

Bohr was slightly stunned, "How are you going to relieve it?"

Margaret smiled affectionately, leaned Bohr against the bed, and then slowly stepped back.

Bohr's heart suddenly trembled, as if he had been electrocuted.

There was only one thought in his mind now: Fuck physics!

(End of this chapter)