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

After dinner, Conan Doyle got a set of Star Wars series from somewhere and asked Li Yu to sign it: "I also like this set of science fiction novels, but unfortunately I didn't bring them with me, so I had to temporarily buy them from other crew members. I bought a set."

Li Yu smiled and said: "Then you also have to sign this set of "The Complete Works of Sherlock Holmes" for me. This is called reciprocity."

Conan Doyle took out a pen, signed his name, and then asked: "Do you have any Eastern-type detective stories, Academician?"

Detection is a big theme. Although Li Yu has not studied it carefully, he has watched many related movies.

——I’ve never seen a pig run away, and I’ve eaten pork before.

Li Yu casually told him a story about "Manslaughter", but made some slight changes in time and placed the background in Guangzhou.

Conan Doyle really liked it after hearing this: "It's a very good story! Is there anything more mysterious?"

Li Yu asked: "What do you mean by mysterious?"

Conan Doyle said: "There should be many strange and unpredictable legends in the East. For example, I know the concept of the underworld after death."

Li Yu said: "Those are fairy tales."

Conan Doyle said: "I believe that souls definitely exist, and that through some means, such as through mediums, people can definitely communicate with souls."

Li Yucai learned that this top detective novelist was also a believer in "spiritualism", that is, a person who believed in the existence of the soul.

Li Yu asked: "Mr. Doyle, if there is a soul, in what form does it exist?"

Conan Doyle said: "Energy, or electromagnetic waves."

Nowadays, the influence of science is extremely strong. Regardless of whether you study science or engineering, you must know some scientific knowledge, otherwise you will really fall behind.

As one of the hottest scientific topics at present, the emergence of electromagnetic waves has indeed provided a lot of "theoretical support" for "energetics".

Li Yu said: "Both energy and electromagnetic waves can be easily detected through instruments, but energy is difficult to maintain a certain shape, and it is not mysterious; as for electromagnetic waves, they propagate at the speed of light. If ghosts are electromagnetic waves, they will circle around in one second. The earth rotates several times and there is no time to speak a single letter.”

Conan Doyle thought for a moment and asked: "How many times around the earth in one second?"

Li Yu said: "Almost seven and a half circles."

"It seems that there are loopholes in this statement," Conan Doyle touched his pipe, and then said, "But I firmly believe that there are other forms that can allow spirits to exist, because I have seen mediums communicating with ghosts. "

Li Yu said: "Ghosts have no vocal cords and seem unable to speak; they also have no neurons and cannot think. I really can't figure out how they can communicate."

Conan Doyle had met many people who opposed spiritualism, including church members, but this was the first time he had seen people opposing spiritualism in such a rigorous scientific way.

But Conan Doyle was adamant: "I will find direct evidence."

Li Yu smiled and said: "I'm afraid this will be countless times more difficult than developing an antidote for tuberculosis."

Conan Doyle leaned back in his seat: "There are so many things to do, there is almost no time to rest. The recent writing plan has to be postponed for a while, and I will study the method of communicating with souls with psychics."

-

After the ship arrived at the Port of London, a middle-aged man was waiting for Conan Doyle at the dock.

"Mr. Barry, how long have you been waiting?" Conan Doyle asked.

Barry said: "It's not long, less than an hour."

Conan Doyle said to Li Yu: "This is my friend, a novelist. If you have children, you can buy a copy of "Peter Pan" written by him. It is very interesting."

Li Yu said: "Thank you for the suggestion."

James Barrie said: "Hurry up, Dr. Doyle, we can't make it to the cricket match today!"

Conan Doyle picked up his suitcase: "I didn't even have time to go back to my house."

Barry said: "I have hired a carriage to take you back after the game."

Conan Doyle turned back to Li Yu and said, "Sorry, Mr. Li Yu, we will see you another day."

When Barry heard Li Yu's name, he asked, "Are you the young academician from the East?"

Li Yu said: "Hello, Mr. Barry."

Barry said: "It's a pity that this meeting is too hasty. Will you go to the cricket match with us?"

Li Yu spread his hands: "I don't understand the rules of cricket, so forget it."

"What a shame," Barry said.

Conan Doyle then got into his carriage and the two of them left first.

Li Yu came to Cambridge University, where a physics lecture hosted by Thomson had just been held, focusing on the increasingly popular theory of relativity.

Although Li Yu missed the lecture, he met Bohr, the super boss of quantum mechanics, after the lecture.

He had just been promoted to lecturer, and the process was much smoother than that of the great master Einstein.

"Mr. Bohr, would you like to have a cup of afternoon tea together?" Li Yu asked.

"It turns out to be Mr. Li Yu!" Bohr said, "You actually also like this British time-wasting habit."

Li Yu smiled and said: "After all, I don't have an office here."

The two came to a tea restaurant and each ordered black tea and snacks.

Bohr's suitcase was very full.

Li Yu asked: "Are you also interested in the theory of relativity?"

Bohr said: "Actually, I only participated in place of Mr. Rutherford, but some of the ideas in the theory of relativity are indeed quite interesting."

Li Yu looked at the suitcase and asked, "The paper you wrote?"

"It was just the first draft, and I discovered a very shocking thing, which may explain the atomic stability problem that has troubled people for many years," Bohr said gushingly. "Classical laws of physics cannot be applied to the microscopic atomic level. If it can be Like Planck, Einstein and Mr. Li Yu, if you focus on quantum and establish a new theory, a theory that is different from the classical laws of physics, it seems that you can perfectly solve the problem of atomic stability. question."

Li Yu immediately understood that what was in the suitcase was the energy level theory that Bohr had been studying for the past two years - an important cornerstone that laid the foundation of quantum mechanics in the early 20th century.

Li Yu asked: "It sounds like you still have some problems that are difficult to solve?" "Yes," Bohr did not shy away. "I have discussed it with Professor Rutherford several times. If I can get some more enlightenment from you, That would be great.”

Li Yu said: "Please speak."

Bohr took out some of his manuscripts: "I made some progress on the problem of dispersion. But in the process I encountered serious difficulties originating from the instability of the system. This difficulty prevented me from carrying out the calculations to all the points. Level of hope.”

Li Yu looked at his manuscript and said, "Your mathematical foundation is very good."

Bohr said: "But I have tried many methods, but I still can't find the golden key on how to combine quantum concepts into Rutherford's model."

Bohr has come very close to the theory of energy levels and has only encountered some minor mathematical problems.

Li Yu could see the problem at a glance, so he said: "Mr. Bohr, can your atomic structure theory explain some of the spectral formulas of atoms?"

Bohr was stunned and said: "I have never considered this problem. The spectrum is so complicated, I'm afraid my atomic structure model has no hope."

Li Yu said: "The spectrum is not complicated. There are rules in it, and someone has already summarized it, which is called Balmer's formula."

Li Yu wrote Balmer's formula on a blank piece of paper. The formula is very simple.

Among the four major problems in physics at the beginning of the twentieth century, one was the problem of the spectrum of hydrogen atoms, and it should have been the first to be raised.

It happened that a Swiss mathematician named Balmer was struggling to study any difficult problems at the time, and felt very boring.

A university physics professor then said to him: "Learn about the hydrogen atom spectrum!"

Unexpectedly, Balmer was very talented in mathematics. Just two weeks later, he gave Balmer's formula, which summarized it quite well.

However, this formula is obviously an empirical formula, which Balmer came up with based on mathematical intuition. As for why it matched so well, he himself didn't know.

For a master of Bohr's level, just a little bit would be enough.

When he saw Balmer's formula, he immediately shuddered, put down the black tea in his hand, picked up the piece of paper tremblingly, and murmured a few minutes later: "It's clear, all the problems are clear to me!"

Balmer's formula (listed in the comment area at the end of the chapter) not only summarizes the spectrum of hydrogen atoms very well, but also has the biggest feature: it can only take positive integers.

Whenever the words "positive integers" and "discontinuity" are mentioned, they are inextricably linked to quantum theory.

Bohr picked up the pen and immediately calculated.

Li Yu had a good time drinking tea and snacks nearby and continued reading "The Detective Sherlock Holmes".

About an hour later, Bohr said happily: "I have derived Balmer's formula!"

In fact, Balmer's formula is just a special case of Bohr's energy level formula.

Then he said excitedly: "Based on the formula, I have a bold idea. The inside of an atom can only release energy at a specific energy level, which means that electrons can only convert between specific potential energy positions.

"That is to say, electrons can only move in certain specific orbits. These orbits must meet certain potential energy conditions, so that when the electrons transition between these orbits, they release energy at a specific energy level and comply with Balmer's formula.

"In this process, the energy released or absorbed by the electrons is divided into energy levels, just like the steps going up and down the stairs. They must have a certain height difference and cannot be continuous and arbitrary as assumed by classical theory."

Bohr had already gotten to the heart of the matter.

Li Yu said: "For such a brand-new physical theory, I hope Professor Rutherford will sign it for you."

At present, if you want to publish a paper, most of the papers require the signature of the supervisor.

——Later generations no longer have such a rigid requirement. After submission, the magazine will find someone to review the manuscript.

Bohr said: "Mr. Rutherford has always supported my research, and he will definitely agree."

Li Yu said with a smile: "Mr. Rutherford just launched the planetary model two years ago, and you immediately overturned it."

Bohr was also a little embarrassed: "But Mr. Rutherford also loves truth."

Li Yu said: "There is one more thing I want to remind you. Mixing quantum theory with classical mechanics will cause a lot of trouble, and many people will definitely oppose it. In addition, there is a problem in your hypothesis, maybe you yourself Also realized, that is, when an electron transitions from one stable state to another, at what frequency will it vibrate? From the perspective of classical theory, it seems that you must assume that the electron knows in advance where it will stop. "

Li Yuti's question hit the nail on the head and would spark controversy for more than a decade.

However, quantum mechanics is a process of continuous development and cannot be complete right away. The energy level theory has been completely epoch-making, enough to make Bohr's name undisputed in history.

It can't be overstated.

Rutherford can be called the "Nobel Prize Kindergarten Director", which shows that he is very capable. He signed Bohr's paper without hesitation, but he felt that the paper was too long and asked him to publish it in three parts.

A few days later, three of Bohr's papers were published in the British Journal of Philosophy, titled "On the Structure of Atoms and Molecules", "Monoatomic Nuclear Systems" and "Polyatomic Nuclear Systems".

That is the famous "Bohr Trilogy".

Energy level theory was so familiar to Li Yu that he even knew its evolution direction and how quantum mechanics developed since then.

The energy level theory could only explain the spectrum of hydrogen atoms. Sommerfeld later expanded it to an elliptical orbit and introduced the theory of relativity.

In short, energy level theory is too important for twentieth-century physics.

Li Yu knew that Bohr's theory would definitely arouse opposition from many people, so he immediately wrote an article to express his support for it:

"I firmly believe that this is a huge development in the natural view of physics. When the entire atomic world is shrouded in a mysterious atmosphere, it is Bohr's theory that opens up a new perspective and allows us to see a new world, a very What a wonderful world. I think Bohr's theory was the greatest step forward in the development of quantum theory."

After seeing the paper, the young Moseley (the proposer of atomic number) immediately expressed his support:

"Bohr's theory is having a great impact on physics. I believe that when we really understand what an atom is (which I believe will not take a few years), even if there are errors in the details of Bohr's theory, it will still be worthwhile. Full trust.”

The pioneers and supporters of quantum mechanics are basically young people because it is too subversive.

As the founder of quantum mechanics, Planck did not dare to completely stand on the side of quantum theory. He famously said: "The reason why new scientific facts can achieve victory is not that he convinced all the opponents, but that the opponents died. Eventually the young people familiar with the new science grew up."

There are very few people engaged in quantum mechanics in the UK. Bohr is a Danish, and his mentor Rutherford is not in the quantum mechanics circle. There is only one super figure in quantum mechanics, Dirac, who is only ten years old now.

So Bohr still found Li Yu to continue his research.

"Sir, I estimate that within a week at most, the comments from the European continent will come like flakes."

Li Yuneng guessed this situation: "An international physics conference will be held in the UK in exactly one week. Let's make some preparations in advance."