Chapter 416 Celestial bodies and atoms! Macro and micro! One method of physics can solve all problems!
The establishment of the International Astronomical Union made everyone see Professor Bruce's love for astronomy.
Dyson even smiled and joked to his colleagues:
"Professor Bruce often goes to Greenwich Observatory to watch the stars."
"But he can't even distinguish the most basic constellations."
"Every time he wants me to be by his side to explain it to him in detail."
Dyson’s words made the bosses smile knowingly.
It turns out that Professor Bruce has such a cute and innocent side.
Always watching the other party make a killing in the field of physics, everyone had long thought that Professor Bruce was omnipotent.
Hale said: "I heard that Professor Bruce is not good at doing physical experiments."
"Looking now, he is also not good at experimental operations in astronomy."
"He is a born theoretical astronomer!"
There was no division between experiment and theory in astronomy in this era.
All research must be based on real observational data, including star spectra, positions, sizes, etc.
But the emergence of general relativity obviously goes beyond the scope of traditional astronomy.
Astronomers have new tools to do some theoretical analysis.
And there was one thing that made everyone guess the research direction that Professor Bruce liked.
After the election of various positions at the meeting is completed, there is another arrangement, which is for the astronomers to give reports.
The content of Eddington's report aroused great interest in Li Qiwei.
Eddington has become a super star in astronomy since he demonstrated the bending of starlight.
But he did not dwell on his past glory, but continued to break through himself.
He turned his research direction to the formation and evolution of stars.
Astronomy can be divided into the following levels according to research objects:
Planetary level, star level, galaxy level, universe.
Hubble's current research direction is at the level of galaxies and the universe, commonly known as large-scale astronomy.
But this does not mean that large scale is more important than small scale.
As the most common celestial objects in the universe, stars have extraordinary significance to humans.
Because without the sun, there would be no basis for human existence.
The earth has been bathed in the sun's rays for hundreds of millions of years.
But humans know almost nothing about the big fireball above their heads.
Therefore, the study of stars is also the hottest direction in astronomy.
And the two most important unsolved mysteries:
First, where does the star's energy come from? Why can stars burn for billions of years without burning out?
Second, what will be the final outcome of the star? Will it turn into dust and dissipate in the vast universe?
Before 1900, these problems were unsolvable.
In professional terms: history has not yet reached a stage where it can be resolved.
But with the advent of general relativity, quantum theory, atomic structure and other theories one after another.
It is possible to break through the secrets of stars.
Obviously everyone in later generations will know that a star will go through four stages from birth to death:
The first stage is the birth of stars, also called the primitive nebula stage.
The huge amounts of gas and dust scattered everywhere in the universe are gathered together due to gravity.
As the accumulated mass becomes larger and larger, the gravitational pull becomes stronger and stronger, causing the temperature and pressure inside the nebula to begin to increase.
So we entered the second stage: the mature main sequence star stage (never mind the concept of main sequence star, just understand it as a mature body).
The huge pressure and extremely high temperature inside the nebula make nuclear fusion possible.
The first nuclear fusion to occur is the conversion of hydrogen atoms into helium atoms.
The huge energy generated by nuclear fusion increases the pressure inside the nebula, thus counteracting the collapse effect of its own gravity.
When the two reach a state of mutual balance, a stable star is officially born.
This is the source of stellar energy: nuclear fusion.
However, no matter how big a star is, its mass is limited.
One day, all the hydrogen atoms in its body will be consumed and turned into helium.
At this time, hydrogen fusion cannot be maintained.
The evolution of stars has also reached the third stage: the red giant stage.
At this stage, although the hydrogen atoms are gone, fusion is still taking place.
When the temperature reaches 100 million degrees, helium nuclei undergo complex changes and fuse into oxygen nuclei. This step is called helium combustion.
As the temperature continues to rise, fusion continues to occur.
From low atomic number elements, they gradually fuse into high atomic number elements.
Until the ultimate limit: iron.
Nuclear fusion inside all stars stops when iron is produced.
Because iron fusion is a special process, when two iron nuclei fuse, they no longer release energy, but absorb energy.
This results in the temperature and pressure required for nuclear fusion being unable to be maintained.
Therefore, the formation of iron is a sign that the star is dying.
At this stage, the interior of the star continues to collapse due to gravity, but the outer material continues to expand and eject various materials.
The size of the star continues to grow, eventually forming a red giant.
At this time, if the original mass of the star is extremely large (tens to hundreds of times the mass of the sun) and exceeds a certain limit, a supernova explosion will occur.
This is one of the most terrifying celestial phenomena in the universe.
The luminosity produced by a supernova explosion is equivalent to the combined luminosity of hundreds of billions of stars in the entire Milky Way.
The energy released in an instant is equivalent to the total energy released by the sun in 10 billion years.
It was the unwilling roar of the star before its death, which was extremely sublime and swept across everything.
This is a "natural disaster" in the true sense, and no means can stop it.
An old star with a short life span comes with the Emperor Supernova and asks you if you are afraid.
In the end, only a small amount of dust remained where the star was located, and it was blown away by the cosmic wind and permanently dissipated between the sky and the earth.
Of course, most stars in the universe have small masses (several to dozens of times the mass of the sun) and will not explode as supernovae.
They will lead to another ending.
This is the fourth stage of stellar evolution: the terminal evolution stage.
At this stage, stars generally transform into three types of objects.
They are: white dwarfs, neutron stars, and black holes.
Although stars in the fourth stage can no longer undergo nuclear fusion and avoid gravitational collapse.
But its constituent atoms are not so compressible.
Because there are electrons inside the atom, and electrons are difficult to be compressed due to the Pauli exclusion principle.
This resistance is called electron degeneracy pressure.
Therefore, when the star's own gravity and electron degeneracy pressure balance, a white dwarf is formed.
But there is an upper limit to the mass of white dwarfs.
When its mass exceeds 1.44 times the mass of the sun, the gravitational force it generates will be greater than the electron degeneracy pressure.
At this time, the atom is crushed, and the electrons and protons are pressed together to form neutrons.
There is also neutron degeneracy pressure between neutrons, which prevents neutrons from being easily compressed.
When gravity and neutron degeneracy pressure balance, a so-called neutron star forms.
Neutron stars are the densest celestial objects discovered by humans so far, except for black holes.
A neutron star with a diameter of ten kilometers would have the same mass as the sun. Each cubic centimeter of neutron star material has a mass of up to one billion tons, which is simply terrifying.
However, the evolution is not over yet.
Neutron stars also have a mass limit.
When the mass of a neutron star exceeds 2-3 times the mass of the sun, its gravity will crush everything.
At this time, the star will become the ultimate celestial body in the universe: a black hole.
As for whether the black hole has further evolved, the current astronomical community does not know.
The above are the four stages in the stellar evolution process.
The specific process is very complicated, and there are many special circumstances, but the core remains unchanged.
It can be seen that stellar evolution is closely related to the research progress of atomic structure.
When physicists did not discover protons and neutrons, it was impossible to understand the internal structure of stars.
Macroscopic and microscopic, the greatest celestial body and the tiniest atom are perfectly combined through physics.
In real history, Rutherford proposed the hypothesis of elemental transformation and discovered the proton in 1919, and the secret of the atomic nucleus was initially revealed.
The ideas of nuclear fusion and nuclear fission began to sprout.
In 1920, Eddington first proposed that stars were powered by nuclear fusion, but did not provide proof.
It was not until 1929 that physicists theoretically calculated the possibility of hydrogen fusion into helium at high temperatures.
In 1931, Raman's nephew, Chandrasekhar, proposed the upper limit of the mass of white dwarf stars based on the special theory of relativity. This limit is called the "Chandrasekhar limit".
In 1932, under the guidance of Rutherford, Chadwick discovered the neutron.
Then, in 1936, Oppenheimer proposed an upper limit on the mass of neutron stars. This limit was called the "Oppenheimer limit".
Ridgway had had an idea before.
That is to guide others to study nuclear fusion, while he himself leads China to study nuclear fission.
This is very possible because nuclear fusion is of great significance in the field of astronomy.
Research on nuclear fusion is much earlier than nuclear fission.
Now, it seems that that time has finally arrived.
But Li Qiwei's ideas are a little different from before.
As Eddington shared his research on the inner structure of stars, Ridgway asked several questions.
So this made the big guys present think that Professor Bruce was interested in stellar research.
After all, to theoretically analyze the composition and structure of stars, there is no need to know any constellations, and it doesn't even matter if you don't even know how to use a telescope.
Theoretical physicists are so stupid.
Eddington seemed very excited when he saw that Li Qiwei was interested in his research.
This made him feel flattered and had his cards turned over by a boss.
After the founding meeting, Eddington, Dyson and others returned with Li Qiwei.
On the way, Eddington said happily:
"Professor Bruce, I really didn't expect you to be interested in stellar research."
"I thought you would continue studying the expansion of the universe."
Li Qiwei casually spread his hands and joked:
"Director Dyson knows that I am not even familiar with telescopes yet."
Several people laughed.
Eddington didn't know whether to laugh or cry. Boss, you are too casual.
He even suspected that what Professor Bruce meant by studying astronomy was that he was tired of studying physics and just did it in his spare time.
But Eddington had a strong hunch that even with casual research, Professor Bruce would publish results that would shock the astronomical world.
After all, that was Professor Bruce, and no one knew where his limits were.
He chatted with Hubble and easily solved the problem of catalysts for artificial ammonia synthesis.
Attending a biology conference, concepts such as gene mutation and gene chain were raised on the spot.
Nowadays, when studying astronomy, publishing blockbuster results is simply a matter of course.
At this time, Eddington then asked:
"Professor, which direction will you study specifically?"
"I also want to be a reference. If I encounter problems in the future, I can ask you for advice."
Dyson on the side was also curious.
He absolutely approved of Li Qiwei's study of astronomy.
The Quantum Institute is so close to the Greenwich Observatory. Professor Bruce will definitely benefit the most from any achievements he has made.
Dyson was even thinking about sending everyone at the observatory to Professor Bruce for further training.
In this way, the strength of Greenwich Observatory will definitely be greatly improved.
As for astronomy and physics they are different subjects.
Dyson said: "For Professor Bruce, does it make any difference?"
Facing Eddington's question, Li Qiwei smiled slightly.
"I might study the energy problems of stars."
"I think this question is very interesting."
"Why does the sun burn for so long?"
"Where does its energy come from?"
"If we humans master this power, we will no longer have to worry about energy in the future."
"In addition, are there any differences between the various celestial bodies in the universe?"
"For example, why do black holes and stars have different properties?"
"Wait."
"Just think of it as a pastime in your free time."
"Maybe I will have to ask you for advice more often in the future."
Wow!
Li Qiwei's words immediately made Dyson, Eddington and others in awe.
They study astronomy, either for their own fame or fortune, for their dreams, or for their jobs.
But look at Professor Bruce.
Even when I was studying astronomy, I was thinking about the fate of mankind.
This is the big boss’s mind.
As expected, people are more irritating than others.
Everyone respected Li Qiwei beyond measure.
"How can there be such a perfect scientist in the world!"
However, Eddington suddenly felt a little pain in his chest, as if he had lost something most precious.
He murmured to himself: "It seems that I can't stay up late as often lately. I need to pay attention to rest."
It's a pity that Eddington didn't have the opportunity to talk to Professor Lorenz, otherwise maybe the two of them could find some clues.
Just when Ridgway made a high-profile appearance in the field of astronomy and raised the debate of the century, it caused a sensation.
On the other side, his best friend Rutherford is about to make his voice equally high-profile in the atomic realm.
Rutherford and Li Qiwei are known as the two unparalleled descendants of the Cavendish Laboratory.
But under the dazzling light of Ridgway, many people have forgotten Rutherford's amazing talent.
The big man who accidentally won the Nobel Prize in Chemistry for his physics achievements has been silent for too long.
This time, he will shine his own light to the fullest.
(End of chapter)