1900: A physics genius wandering around Europe

Chapter 214: The Brilliance and Dark Clouds of Classical Physics
On July 1909, 7, Gregory and others finally completed the compilation of all the information.

Li Qiwei began a three-day retreat.

He tried to connect classical physics and modern physics with a clear thread.

The original manuscript will certainly not be shown to the world, and his October speech will only contain excerpts from it.

Because his manuscripts will contain all the major events in physics in the next twenty or thirty years.

Any one of them is a Nobel Prize-level achievement.

What an ordinary physicist seeks throughout his life may be just a trivial paragraph in a manuscript.

In the fantasy world, this is definitely the supreme artifact, the Book of Truth.

Looking at the neatly organized papers and research contents by several doctoral students in front of him, Li Qiwei felt deeply moved.

He finally got to this point.

From the highest perspective, we can sort out the history of physics and open up new directions and paths for future generations.

This should be regarded as carrying on the lost knowledge of the ancient sages and bringing peace to the world for all eternity!

Although at this point in time, there are still many theories and phenomena in physics that have not been discovered.

But decades later, Li Qiwei will inevitably do something similar again in a noble capacity.

The history of physics is different from the traditional history of civilization. Without sufficient knowledge of physics, it is impossible to write a logically consistent story.

He put aside all distractions and began to write.

The 19th century was the most glorious period for classical physics.

Classical physics consists of three major theories: Newton's mechanics, Maxwell's electromagnetic theory, thermodynamics and statistical mechanics.

The three major theories are responsible for physical phenomena such as force, light, electricity, magnetism, and heat. They echo and complement each other and can explain the laws governing the operation of all things in the world.

As for other phenomena such as sound and waves, they are just combinations and extensions of these three theories.

Every theory has its core and milestone moments.

The core of Newton's mechanics theory is Newton's three laws and the law of universal gravitation.

In 1846, physicists successfully predicted the existence of Neptune through the law of universal gravitation and found it.

Neptune is also known as the "planet on the tip of the pen".

This is the highest moment of Newtonian mechanics.

With just a pen, humans have calculated great things like celestial bodies and have conquered nature with their weak bodies.

From then on, Newtonian mechanics was placed on a pedestal; it was authoritative, sacred, and true.

French physicist Laplace was even bolder. He imagined a Laplace beast.

It can obtain the motion state of all matter in the universe and know the interactions between matter.

Then according to the calculations of Newtonian mechanics, Laplace Beast can know the past, present and future of the entire universe.

This view of the universe of absoluteness, continuity, and causality is the philosophical view of Newtonian mechanics.

This idea governs everyone.

Physicists who grew up under this kind of thinking are called classical physicists.

Including Lorentz, Planck, and even Einstein.

This is also why Lorentz was just one step away from the theory of relativity, but he never dared to take that step, because the theory of relativity violated absoluteness.

Why did Planck open the door to quantum theory but dare not go further? Because quantum theory violates continuity.

Until his death, Einstein was unwilling to accept the probabilistic interpretation of quantum mechanics because it violated causality.

As a great figure who emerged in the era of transition between old physics and new physics, Einstein has a kind of contradictory beauty.

Despite countless objections, he insisted on the theory of relativity, but believed that quantum mechanics was wrong.

Of course, these are things for later.

After Newtonian mechanics came Maxwell's electromagnetism.

Its core is Maxwell's equations, and its highlight is the discovery of electromagnetic waves.

In fact, the two phenomena of electricity and magnetism had been studied by many people long before Newton.

Because they are so common, lightning and magnets exist in nature, and it is difficult not to notice them.

But it wasn't until the early 19th century that physicists discovered the connection between the two.

In 1819, Danish physicist Oersted discovered that a compass placed next to a current-carrying wire actually deflected.

Then, French physicist Ampere went a step further and discovered that there would be an attraction between two wires carrying currents in different directions.

If the current is in the same direction, repulsive force will be generated.

This shows that a wire carrying current actually generates a magnetic field, the so-called electromagnetism phenomenon.

Later, British physicist Faraday came up with a reverse thinking. Since electricity can generate magnetism, can magnetism generate electricity?

He did an experiment in which he placed a magnet in a spiral coil and let the magnet move up and down. As expected, an electric current was generated in the coil.

This is the phenomenon of electromagnetic induction.

So, physicists began to think about why electricity and magnetism, two seemingly completely unrelated phenomena, have such connections and effects.

It was not until Maxwell came along and published the Maxwell equations that unified electricity and magnetism.

He proved that electricity and magnetism are just different manifestations of the phenomenon of electromagnetism.

Moreover, Maxwell's equations predicted the existence of electromagnetic waves and calculated their speed to be c, the same as the speed of light measured at the time.

Therefore, Maxwell believed that light is an electromagnetic wave.

Eight years later, German physicist Hertz actually discovered electromagnetic waves in the laboratory and measured their speed and found that the result was the same as the result calculated by the equation.

At this point, Maxwell was completely deified, and his electromagnetic theory was perfect, just like Newtonian mechanics.

The last two, thermodynamics and statistical mechanics, do not have a name in front of them because their birth is the result of the joint efforts of many physicists.

Unlike Newton and Maxwell, who created a theory entirely on their own.

At the core of thermodynamics and statistical mechanics are three laws.

In fact, the three laws of thermodynamics had already been established before 1900.

Although the third law was not published until 1906 by Nernst, it was only the final confirmation process.

The first law of thermodynamics is the law of conservation of energy, proposed by Joule in 1850, and its core parameter is internal energy.

All physicists now assume that this law is correct.

The first law also proves that a perpetual motion machine of the first kind (a machine that can continuously perform work automatically without consuming any energy) is impossible.

The second law of thermodynamics is the principle of entropy increase.

It was perfected through the efforts of several great men such as Clausius, Lord Kelvin, Maxwell, and Boltzmann.

Clausius was the first to propose the concept of "entropy", and Maxwell was the first to use statistics to describe macroscopic gases.

At that time, atoms had not yet been proven to exist. Maxwell assumed the existence of atoms and then used statistics to explain the pressure and temperature of gases.

The boss is really awesome, and he is awesome in any field.

Thermodynamics was just something Maxwell did for fun when he was bored.

Lord Kelvin proposed the standard statement of the second law: it is impossible to absorb heat from a single source and convert it entirely into useful work without producing other effects.

This law also completely denies the existence of the second type of perpetual motion machine.

Later, Boltzmann inherited Maxwell's ideas and linked entropy with the disordered state of the system.

From the perspective of statistical mechanics, the second law of thermodynamics is redefined using probability.

This is why thermodynamics and statistical mechanics are often discussed together.

This idea of ​​statistical mechanics also provided inspiration for Einstein later.

Next, Nernst discovered the third law of thermodynamics, which completely completed the theory of thermodynamics.

At this point, the three major theories of classical physics were all completed, shining brightly, extremely sacred, and dominating the material world.

Any phenomenon in nature can be explained by these three theories.

As large as the movement of celestial bodies, as small as an apple falling to the ground; as fast as electromagnetic waves, as slow as mechanical waves; as hot as the power of the sun, as cold as the power of extreme cold.

The three theories are unbreakable, like gods, and dominate the world.

That is why physicists become arrogant and think that physics is already perfect and there is nothing more to study.

This was the context of Lord Kelvin's report in April 1900.

He believes there are only two dark clouds in the physics community at present.

However, in the distance, there were actually a few small dark clouds, but the physicists at the time did not pay attention to them.

If we say that classical physics is a place where many talented people emerge and great masters compete on the same stage.

Then the genius of modern physics is like a shooting star, so brilliant.

Li Qiwei smiled when he wrote this, and then modern physics, which brought about various subversive phenomena, emerged.

The first dark cloud was related to Maxwell's electromagnetism, namely the Michelson-Morley experiment, which found that the ether did not exist and the speed of light was constant.

This led to the publication of the special theory of relativity by Ridgway and Einstein.

And next will be the general theory of relativity that will shock the world. Of course, Li Qiwei is not ready yet.

The second dark cloud is related to thermodynamics, that is, the law of equipartition of energy encounters problems in blackbody radiation.

This led to the publication of quantum theory by Ridgway and Planck.

In the future, Bohr will apply quantum concepts to atomic structure and propose quantized orbits.

This would be the culmination of the old quantum theory.

In real history, Planck, Einstein and Bohr were the three giants of the old quantum theory.

But now, the Big Three will become Planck, Ridgway and Bohr.

But even by that time, quantum theory had not yet evolved into quantum mechanics.

It was not until Heisenberg proposed matrix mechanics that quantum mechanics truly became a theory and was subsequently continuously improved.

The story that happened in the middle involves many physicists.

Li Qiwei slowly recorded it in chronological order.

In addition to the two dark clouds above, there are several smaller dark clouds.

The first small dark cloud is the photoelectric effect, which has been solved by the photon proposed by Li Qiwei.

In real history, it was Einstein who solved it, which is why he is called one of the three giants of the old quantum theory.

Because the concept of photons is to treat light as individual quanta.

Although Millikan has confirmed the correctness of the theory, many physicists still do not believe that light can be quantum.

Because they can't imagine this picture.

The second small dark cloud is the problem of the spectrum of elements, that is, spectroscopy.

It is a discipline that studies the interaction between electromagnetic waves and matter.

Hundreds of years ago, Newton used a prism to decompose sunlight and discovered the simple spectrum of the sun.

Later, physicists used more advanced optical instruments such as gratings to analyze the wavelength distribution of a beam of electromagnetic waves.

The image of electromagnetic waves of various wavelengths arranged on the panel is called a spectrum.

In the 19th century, Germany was the center of optical research, and the problem of blackbody radiation was first proposed and studied in Germany.

Around 1850, German physicist Kirchhoff discovered the radiation spectrum of elements.

At that time, people didn't know whether atoms existed or not.

The so-called chemists can only measure the change in weight before and after the reaction, or burn the elements in fire.

Hey, you nevermind, this burning will produce a significant result.

Chemists have discovered that each element has its own specific color when burned by flame.

For example, potassium is purple, sodium is yellow, and calcium is red.

We in later generations know that these are flame color reactions caused by electron transitions.

But scientists at the time didn't know that.

Later, when Kirchhoff learned about this phenomenon, he became very interested.

He built a spectrometer to analyze the spectrum of light emitted by these elements when they were burned.

He discovered that the radiation spectra of the elements were separate lines, like a bar code, rather than a continuous spectrum.

Then, he conducted experiments and recorded the radiation spectra of all the elements known at that time.

In the future, if you get a ball of unknown substance, you just need to burn it on fire and analyze its spectrum to know the constituent elements of the substance.

Later, Kirchhoff claimed that he knew the composition of the sun.

This immediately caused an uproar and a huge shock in the scientific community.

Everyone found it incredible, but when they understood Kirchhoff's theory, they found that it seemed that they could indeed understand the composition of the sun.

Because all we have to do is analyze the sun's emission spectrum.

But after the excitement, physicists began to have questions.

How is the emission spectrum of an element formed?

Why are these spectra separated lines and not continuous?

Why does the emission spectrum of each element differ?

In real history, these problems will be solved by future Bohrs.

The third small dark cloud is the problem of the arrangement of the periodic table.

Although the great Mendeleev created the periodic table that shocked the world, he arranged the elements according to their atomic weight.

For example, the atomic weight of hydrogen is the smallest, which is set to 1.

The other elements are compared with it in order of weight, and different atomic weights are placed in different positions.

However, with Rutherford's discovery of the nature of the radioactive phenomenon.

People have discovered many new elements, which have exactly the same chemical properties as certain elements, but different atomic weights.

So where should these new elements be placed in the periodic table?
In real history, this problem was perfectly solved after Soddy proposed the concept of isotopes.

Soddy's achievements were almost all based on Rutherford's experiments.

This shows how humble chemists were compared to physicists in this era.

In the eyes of the world, chemists are alchemists who have no theory at all.

The physicists' casual leaks are enough for chemists to digest for a while.

No wonder it is said that the essence of chemistry is physics.

As for the fourth small dark cloud, Li Qiwei put the "field" up.

Electric fields, magnetic fields, etc., the physicists at this time were not unfamiliar with the concept of fields.

It is easy to use it to solve problems.

However, the field cannot be seen or touched, but it exists, just like a ghost.

No one knows what the nature of the field is.

Later, Dirac combined field and quantum mechanics to create quantum field theory, which profoundly influenced later physics.

Li Qiwei stopped writing after this.

He finally sorted out the most important problems encountered in classical physics.

Next, there are more problems discovered by experimental physicists.

For example, Roentgen's X-rays, Madame Curie's radioactivity, Thomson's research on atomic structure, and so on.

These are all part of modern physics.

This was also the main research content of physicists from 1900 to 1909.

With the addition of relativity and quantum theory, the new and old physics are clearly distinguished.

These new theories and phenomena are what truly open the door to physics and allow humans to glimpse the face of truth.

The classical physics edifice that once made all physicists proud began to shake.

The new building has just laid its foundation and has not yet shown its brilliant side.

This is the best of times. The old gods have fallen, but the new gods have not yet returned.

This is also the worst era. The development of physics has gradually surpassed human imagination, and even the nature of the world has become blurred.

Even the true God can be blinded sometimes.

Li Qiwei suddenly felt very proud.

As the co-founder of relativity and quantum mechanics, he naturally knows how exciting the future will be.

All those exciting theories and discoveries are inseparable from him.

He wants to surpass all gods and become the god of gods!
This may be the only update today, but the number of words actually counts as 2 updates.

The following plot is still difficult to write, and the author needs to check the information carefully.

The key is to write it smoothly and correctly. Wow, it's too difficult.

And for the convenience of readers, I have to popularize a lot of content. This makes the content a little cumbersome, I hope you don't mind.

Because if it is not written clearly, everyone may not know what the fun is.

I can’t just pad the word count and say, wow, this theory is awesome and everyone worships it.

Everyone will only have: ??? Black question mark face.

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(End of this chapter)