A Man of Science and Engineering in Troubled Times Wandering in the Late Qing Dynasty

It is said that the 1927 Solvay Conference was a fight between gods. Strictly speaking, it should be a group fight.

Because fights between smaller immortals often happen at this time.

Li Yu's reputation is already very high. His attendance and distinctive attitude, coupled with the emergence of novel physics theories, brought a large number of top physicists to the Science Promotion Conference held in Birmingham, England.

Just to name those who have won the Nobel Prize, the British include Thomson, Rutherford, Ramsey, and Rayleigh.

From the European continent came Bohr, Lorenz, Laue and Einstein.

Including Li Yu, there are a total of nine Nobel Prize winners. This level of concentration is difficult to imagine in future scientific conferences.

Among them, Laue and Einstein from Germany came on behalf of the Berlin Academy of Sciences and Göttingen.

As the current European science and technology center, Germany's attitude is very critical. After all, Germany was the first to develop quantum mechanics.

As for Germany's attitude, the participants actually saw it very clearly: Laue and Einstein belong to the younger generation of German scientific circles, not leaders; secondly, Laue and Einstein's attitudes towards energy level theory are not the same. The unification shows that the German scientific community does not have a unanimous view on energy level theory, so it sent one supporter and one opponent.

As Bohr's mentor, Rutherford presided over the meeting. After a brief speech, he deliberately asked Li Yu to come on stage to state his views.

Li Yu understood that he was a typical calf-protector because he was a firm supporter of quantum theory.

If Thomson were to come to power, he would probably severely criticize quantum theory and make it impossible for Bohr to step down.

To be honest, Rutherford himself was skeptical of energy level theory. After all, he is an experimental physicist and believes more in experimental verification than in the equations, formulas and mathematical derivation of theoretical physicists.

But overall, Rutherford was in favor of Bohr, and he only targeted the imperfect parts of the energy level theory.

Some scientists, unlike Rutherford, fundamentally deny and oppose the energy level theory.

Facing such a group of big guys who are well-known in textbooks, Li Yu used to be quite nervous. But then I thought about how I might have to take textbooks, so I gradually stabilized my mentality.

——But it still feels very exciting.

Li Yu came to the stage and said: "Dear professors and academicians, you must have read Mr. Bohr's paper. It must be admitted that this is a very important paper and a remarkable progress. Bohr achieved real success. When Bohr said that Planck's constant h will be the key to understanding atoms, I believe everyone must understand the weight of this sentence.

"Dr. Bohr made an ingenious and excellent explanation of the laws of spectrum. One can even add the word 'convincing'. We cannot regard his results as an accidental success, but as a vane of modern physics." .”

Originally, there were many people who were skeptical and opposed to Bohr's theory, and their attitudes were very strong. Because Bohr's energy level theory seriously "violates" the laws of classical physics, it is inevitable to be doubted and opposed.

The speeches of Li Yu and Rutherford gave Bohr a great reputation.

But a few big guys still raised questions.

The first was Lorenz, who asked Bohr: "How should your atomic structure be explained mechanically?"

Lorenz, a leading figure in the world of physics, has a profound foundation in mathematics and physics. His questions are very pointed and difficult to answer.

His words confirmed to a certain extent that classical mechanics could not provide a correct explanation of atomic structure; but the new quantum mechanics had not yet been established, and Bohr's research had just begun, and it was impossible to answer Lorenz's question.

Bohr thought for a long time and felt that the argument would reveal more flaws, so he had to say: "We can only study this issue after we accept quantum theory; and this is something that can definitely be done."

Bohr's show of weakness was wise. Seeing that he was so sincere, Lorenz did not continue to question him.

Thomson's speech was much harsher: "Dr. Bohr, how does your theory explain the problem of hydrogen isotopes?"

Although his question is slightly simpler than Lorenz's, it is still unable to be explained by current quantum theory, and the answer must wait for another ten years for the development of quantum theory.

"Director Thomson, I'm sorry, but I can't answer your question either," Bohr said frankly, "but just because I can't answer it doesn't mean that the energy level theory is wrong."

Thomson said: "Any theory in physics requires experimental verification. If you don't do experiments, can you make experimental theoretical assumptions?"

Bohr thought for a long time and had to put forward his own immature idea: "They may be hydrogen atoms three times the weight of the hydrogen atom nucleus. As for the experiment, I think it can be tested through thermal diffusion experiments of metallic palladium using a mixture of hydrogen and tritium." "

What Bohr said is a little professional, but it is enough for everyone to know one thing: there is currently no concept of neutrons in physics, so no matter what assumptions are made, they are basically wrong.

Sure enough, Thomson and Ramsay shook their heads together. It was difficult for them to accept Bohr's point of view.

Thomson turned his head and discussed with Ramsey in a low voice, and then said: "We think your experimental suggestion is of little value."

Thomson's attitude was somewhat rash, because he really did not believe in Bohr's theory.

Just a few days before this meeting, Thomson had just read out one of his papers "On Atomic Structure."

In this paper, he also proposed a model of atomic structure. Through this model, many phenomena such as the photoelectric effect and quantized absorption of energy can be explained without using any principles other than classical physics.

It sounds very powerful, but if you think about it for a moment, you will know: How can the photoelectric effect be explained without using principles other than classical physics?

In short, the atomic model proposed by Thomson was completely different from Bohr's, and there was an incompatible contradiction between the two.

The eyes of the public are sharp. Even if the physicists present do not agree with Bohr's theory, they will discuss it heatedly, but no one will discuss Thomson's atomic model at all...

Years later, Thomson still did not accept Bohr's theory of atomic structure. In two books on atomic structure published by Thomson in 1914 and 1923, Bohr's quantum theory was not even mentioned.

It was not until his later years, when Thomson was 80, that he mentioned Bohr's 1913 paper in a memoir.

He wrote in the book: "These papers have brought some parts of spectroscopy from chaos to order. I think this is the most valuable contribution of quantum theory to physics."

But this was already 1936. Quantum mechanics had long been recognized by the world, but Thomson only had this little evaluation.

Maybe Thomson does have a certain bias against quantum mechanics.

As Planck said, a new theory must wait until all the old scholars are dead before it can be fully recognized...

The host Rutherford looked at Rayleigh again: "Sire, what do you think of the energy level theory?" Rayleigh, like Rutherford, is a person with relatively high emotional intelligence. He took a puff of his pipe and said slowly: "I One of the many beliefs I firmly held in my youth was that a person over 60 should not express his or her opinion on novel insights. Although I admit, I am not a big believer in this view today, not much. It’s not old, but it’s enough to keep me above this discussion.”

Rayleigh's meaning was clear, neither approving nor disapproving.

Next is the stance of German scholars.

Laue came on stage and said: "First of all, I want to convey the views of Professor Sommerfeld of the University of Munich. He is very interested in Mr. Bohr's theoretical model and thinks it is a major progress. There are many remarkable things in the paper. places, such as more applications of Planck’s constant.”

Bohr couldn't wait to ask: "Does Professor Sommerfeld approve of my theory?"

Laue said: "In fact, Professor Sommerfeld's last words were, 'He is quite skeptical of the general atomic model.'"

Bohr was a little disappointed, but he was too good at showing it.

Laue continued: "In addition to Professor Sommerfeld, Mr. Born also does not believe that your paper is objective and correct. Mr. Born thinks that your assumptions are too bold and whimsical. If the problem of spectrum can be solved, it will indeed It has a sensational effect. But your theory is more like trying to come up with a consistent result through some random numbers."

Germany is already the place with the most in-depth research on quantum theory. Sommerfeld and Born have since become absolute giants in force mechanics. At this time, even they made such statements, which made Bohr even more disappointed.

Bohr was not discouraged: "If I could explain it to Professor Sommerfeld or even Professor Planck in person, they would definitely accept it."

Laue said: "It makes no sense."

Einstein coughed slightly: "Is it my turn to speak?"

Host Rutherford immediately said: "Of course."

After Einstein came to power, he expressed a completely different view from Laue: "I believe that Bohr's theory is just the beginning, and he will definitely have a lot to write about later. I definitely don't believe that he perfectly solved the problem of hydrogen atom spectrum by just relying on luck. "

Einstein had good reason to support Bohr - his special theory of relativity was not popular for a long time.

Bohr today is just like himself in the past, and Einstein felt a sense of sympathy for each other.

Who would have thought that more than ten years later, the two would stand on opposite sides and start a duel between gods.

As for Laue, it was actually just a slightly different point of view. He and Einstein had always been very good friends.

Li Yu continued Einstein's words: "If a formula can perfectly match the experimental results, we cannot simply reject it. Proving a formula and rejecting a formula both require experiments. Now that we don't have both, we can't make any assumptions. The conclusion is drawn. Although Mr. Planck’s blackbody radiation formula is also suspect, who can say that it is meaningless?”

Li Yu's words immediately aroused the support of many people.

After several discussions, everyone agreed that after a few years, the experimental results would be available before making a conclusion on Bohr's energy level theory.

After the meeting, several young scholars including Einstein, Bohr, Li Yu, and Laue went to a restaurant to have dinner together.

"I'm glad that you two can express your support for my theory," Bohr thanked Li Yu and Einstein, and then said to Laue, "Thank you for your doubts."

Li Yu smiled and said: "Theoretical support can only be verbal. In the future, with experimental evidence, everyone will support you."

"Oh! Another experiment!" Einstein felt dizzy just thinking about it. "At least your theory is relatively easy to verify."

Bohr strongly agreed: "What I need most now is a laboratory to verify the energy level theory."

Einstein already had the ideological basis for general relativity at this time, but as we all know, experimental verification of general relativity is quite difficult.

Although general relativity describes the high-speed macroscopic world, the experimental accuracy is outrageous. After all, the universe is too big to be imagined. Gravitational waves, a huge astronomical phenomenon that releases all the energy of several or even dozens of stars, require detection accuracy that exceeds many experiments that study quantum mechanics in the microscopic field.

Moreover, general relativity is even more difficult to understand. Core ideas such as "gravity is the curvature of space" are still unacceptable to a large number of people in the 21st century. Quantum mechanics has already produced countless experimental results.

Fortunately, Bohr won't have to wait too long for now.

There are two important experiments to verify Bohr's theory: the Pickering spectral line experiment and the Frank-Hertz experiment.

Pickering was the observatory director who had a large number of female researchers whom Li Yu met when he went to the Harvard University Observatory.

Needless to say, the experimental data in his hands are so detailed.

It seems that many people have not heard of the fame of the Frank-Hertz experiment, but in fact, Frank and Hertz (the nephew of Hertz who discovered electromagnetic waves) won the 1925 Nobel Prize in Physics for their experiment that verified the Bohr energy level theory.

Interestingly, neither of them recognized Bohr's energy level theory at first, but after the experiment was done, it perfectly demonstrated Bohr's theory.

Fate, amazing.

Millikan also wanted to overthrow Einstein's explanation of the photoelectric effect, but unexpectedly helped Einstein a lot.

But these two experiments will take several years to complete and will have to wait.

Especially in seven or eight months, a war will break out in Europe, and many scientific researches will be forced to slow down or even stop.

Those engaged in theoretical research may not be greatly affected, but European experimental physicists are basically unable to do anything, and many of them were even forcibly conscripted to the front lines.

During World War I, there was no shortage of great scientists on the front lines. Fortunately, these people are basically in the logistics department, engaged in communication research, cryptography research, or ballistic research.

Cambridge sent many mathematicians to the frontline artillery units.

Many scientists who could have made more contributions to human science unfortunately died on the front lines. Perhaps the most regrettable thing was the British Moseley. During the absurd Gallipoli landing battle launched by the British army, Moseley was shot in the head by a sniper and died on the spot.

Many people, including his teacher Rutherford, tried to dissuade him from going to the battlefield, but Moseley refused. If he had lived, he would have been guaranteed a Nobel Prize.

Of course, Britain's losses were relatively small overall. The real tragedy was in France. Doctors didn't even know how many people died...