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

Chapter 367 The Conception of Genius

Many people may only know Rutherford's alpha particle scattering experiment and atomic nucleus model, but Rutherford won the Nobel Prize for his research on radioactivity.

This is very similar to Einstein, another super-super-big guy at the same time: everyone only knows Einstein's theory of relativity, but most of them don't know that Einstein won the Nobel Prize because of the photoelectric effect, an achievement that should belong to the quantum field.

Rutherford's research on radioactivity is still very in-depth, and he has pioneered the concept of "half-life" of radioactivity.

Influenced by Thomson, Owen Richardson also studied rays very deeply.

After listening to Li Yu's statement, Richardson pondered: "To tell you the truth, I have considered Mr. Academician's question, but I doubt whether this kind of radiation should be related to the sun."

Li Yu said: "Your guess can be easily verified to be incorrect. You only need to measure the radiation intensity once during the day and once at night."

"The Academician is right, otherwise it would be too simple," Richardson said.

Rutherford's experiment is very sensitive, and said: "Can we verify it by launching high-altitude balloons? If it increases as the altitude increases, we can verify that the rays come from the universe."

Li Yu said: "This is a first step in the experiment, because the height cannot be placed in space, and if the ray intensity is very high, the range of change will not meet theoretical expectations, and it is difficult to rule out interference from the ground."

Rutherford frowned, and even he didn't have a good idea: "Then how to verify that the rays come from space?"

Li Yu had already had the right idea. He said, "We need to use a new concept in astronomy: penetrating ability. I think you must be familiar with it, that is, the penetrating ability of various rays."

Rutherford naturally knows the field he is currently researching the most: "The penetrating ability of gamma rays is hundreds of times stronger than that of beta rays, and beta rays are a hundred times stronger than alpha rays. It can't be stronger than the strongest gamma rays, right?"

There can be gamma rays on the earth. If cosmic rays can only reach this intensity, with the current experimental methods, it is basically impossible to verify whether they come from the universe.

Li Yu said: "The most critical issue now is to exclude the influence of atmospheric absorption, because if the rays outside the atmosphere are to be measured on the ground, the penetrating power must be extremely large, large enough to pass through water ten meters thick—that is, the general absorption power. But from the currently known natural radioactive elements, there is no radioactive element that can pass through water 2 meters thick."

What kind of person is Rutherford, who knows a little bit, and immediately understands Li Yu's experimental idea: "Mr. Academician is going to put the detection instrument under water more than ten meters deep to detect rays?"

Li Yu nodded: "That's right!"

Rutherford said in surprise: "If it is true as you said, the intensity of this kind of radiation may be several times or even ten times stronger than that of gamma rays. What a terrifying energy! It simply subverts the previous cognition!"

Li Yu could tell from his expression that Rutherford was already very interested, and said with a smile, "How about it, do you want to do it together?"

Rutherford rubbed his hands, and agreed: "It just so happens that I can design such a detection instrument."

This is the biggest purpose of Li Yu looking for Rutherford.

At the current point in time, in terms of experimental ability, if Rutherford says he is number two, others will have to weigh it carefully if they want to be number one.

Li Yu asked Owen Richardson again: "Are you interested?"

Richardson was also itchy: "Thanks to Mr. Academician for the invitation!"

Cosmic rays later became the source of elementary particle research, and their value is very high.In history, the discovery of cosmic rays alone won a Nobel Prize in 1936.

People like Rutherford certainly knew its significance.

Li Yu, as the leader of the experiment, arranged a task for Richardson: "In order to eliminate doubts and interference, we still need to conduct high-altitude experiments. This matter needs to be troubled, sir."

Richardson said: "Sure, I'm going to get rid of the sun first."

Lord Kelvin, President Huggins and Director of the Cavendish Laboratory Thomson were shocked after listening.

Thomson said: "It's incredible, if it is really proved that the rays come from the universe, I can't even imagine what language to describe it!"

President Huggins said: "It is indeed unimaginable. Maybe Li Yu will prove that rays are extremely widespread in the entire universe, and the rays on the earth are only the tip of the iceberg."

The duration of the experiment will not be short, and Li Yu will stay in London for at least one or two months.

According to the experimental plan designed by Li Yu, Richardson's tasks were listed first.

It just so happened that Rutherford was going to the Royal Society to report on his work on the radioactive research of radium element at McShell University in Canada in recent years. This was his main task in coming to the UK this time.

The content of Rutherford's work generally means that the radium element will emit heat (γ-rays), indicating that the atom contains energy; and there is also about his "half-life" theory.

In fact, this is what Rutherford won the Nobel Prize in Chemistry four years later.

As a foreign academician of the Royal Society, Li Yu is naturally qualified to participate in this report.

At the same time, Lord Kelvin, President Huggins, Lord Rayleigh and a large number of British scientific figures also attended the meeting.

Li Yu and the others came to the auditorium of the Royal Society. Although it was not a big place, its influence had always been great.

The layout inside is very similar to the British Parliament you have seen on TV: the speaker sits at a table surrounded by stepped seats.

Lord Kelvin and President Huggins invited Li Yu to sit beside them.

Before the report begins, everyone already knows the general content, especially the pioneering work on half-life measurement of the age of the earth.

This is the first time someone has proposed such an approach.

Rutherford's report is really rich in gold.

There are not many means at the moment, and it is extremely difficult to measure the half-life of an element.But Rutherford conceived a plan like a genius, and it was a very simple and crude plan: rely on manpower to count how many α particles emitted by atoms per unit time!

As long as this value is counted, the half-life of the element is known.

Rutherford completed this research in Canada. He and his assistant Geiger (the Geiger of the Geiger counter) designed an ingenious experiment that can amplify an alpha particle into a current that can be detected.

He thus knew the emission rate of radium element.

卢瑟福甚至还用试验估算出了基本电荷为1.55×10的-19次方库伦，现代数值是1.6。只有3%的误差，真心佩服到五体投地。

You must know that measuring the basic charge is also a Nobel Prize later! (Of course Millikan's experiment was more sophisticated then.)
卢瑟福测出镭元素的半衰期是1500年左右，他敏锐地感觉到有问题：1500年就衰变掉一半，那经过3万年，就只剩下1/2的20次方！

That is less than one part in a million, almost negligible.

The age of the earth cannot be 3 years, right?

How can there be so much radium in nature?If it had existed for tens of millions of years, it should have decayed long ago.

For Rutherford, it's all about guesswork.

He imagined that the element radium was not only decaying but also being produced: radium was the product of the decay of other elements.

The ones most likely to decay into radium are uranium and thorium, since they occur together with radium in the mineral.

Rutherford tends to think that it is the ability produced by the decay of uranium, because uranium contains a lot of radium.

Anyway, it's a genius idea.

Through the half-life of uranium (Rutherford guessed it was several hundred million years, but it was actually 45 billion years), Rutherford estimated the age of the earth to be several hundred million years.

Although the gap with later generations is not small, his thinking is extremely groundbreaking.

The carbon-14 measurement method commonly used in later archaeological research has the same principle as Rutherford.

The thinking of these geniuses is contrary to the theory of Lord Kelvin.

Lord Kelvin once used thermodynamic methods to estimate the age of the earth as 2400 million to 1 million years.

His method is equally simple and crude: he believes that the earth was originally a magma planet, and then the temperature slowly dropped.As long as the initial temperature, thermal conductivity, and temperature gradient are known, the age of the earth can be estimated.

Lord Raleigh was good-natured, and said to Lord Kelvin, "My lord, if this young man on the stage is right, then you are wrong."

Lord Kelvin said, "Then I'd like to hear if there's any flaws."

Lord Kelvin did not believe in Rutherford's theory at this time. Last year, he also questioned Madame Curie's research, thinking that the spontaneous transformation of elements is nonsense.

——It’s indeed a bit embarrassing for the old man, it’s not easy for him to accept the atomic theory, and now someone will explain the decay of elements soon!

Today's young people are really getting more and more outrageous!
In fact, Rutherford was also very nervous, especially after seeing Lord Kelvin in the audience.

With Lord Kelvin's qualifications, if he stood up to object, Rutherford would definitely not be able to close the field.

Li Yu, on the other hand, took the time to sit and watch the play.

It's not that he doesn't want to help Rutherford, but it's so rare to see big guys tearing each other apart!

And Li Yu knew that Rutherford was actually a well-rounded person, so this scene should be held.

Rutherford swallowed, took a deep breath and started his report, sneaking a peek at Kelvin's reaction from time to time on the way.

Although Kelvin is a bit old, his spirit is not as good as that of ordinary people, and sometimes he seems to be asleep.But once Rutherford talked about the key points, he immediately sat up straight, his eyes sparkling.

And Rutherford became even more nervous when he saw his gaze.

He had an idea, and suddenly said directly: "Everyone here must already know that Lord Kelvin has already calculated the age of the earth without heat sources. His prophetic insights are the reason why we are discussing radium here today! Without him, my research would not exist!"

As soon as Rutherford said these words, Lord Kelvin really looked good, and couldn't help but smile from the corner of his mouth.

Li Yu sighed in his heart: he deserves to be the principal of the kindergarten!
If it were Marie Curie on stage, it might be sparks hitting the earth by now.

Reporting has been smooth sailing since then.

After the end, Li Yu was the first to applaud.

Then he said to Lord Kelvin: "Lord, do you now accept the theory of atomic transformation?"

Lord Kelvin shook his head: "At least for now, I can't fully agree."

Li Yu smiled and said, "Shall we make a bet?"

"Bet me? I've never lost! President Hudgens can testify that he has lost to me how many good Cuban cigars," said Lord Kelvin.

"I can certainly testify," said President Hudgens.

Li Yu was not afraid: "I bet you will accept Rutherford's radiation theory in a short time, not more than three months."

Lord Kelvin asked: "What's the stake?"

Li Yu said, "How about a pound?"

Lord Kelvin said without hesitation: "Okay, it's a deal!"

(End of this chapter)