Shulou(Shulou.com)11/24 Report--

This article comes from the official account of Wechat: back to Park (ID:fanpu2019), by Cao Zexian (Institute of Physics, Chinese Academy of Sciences)

If the sky does not give birth to Zhongni, it will be like a long night.

-- [Song] Tang Gui

Galileo is the founder of modern science and modern physics, and is praised as the mathematician blessed by God, Archimedes of Tuscany, the real connoisseur of art and science, the gifted craftsman and the martyr of academic freedom. Galileo brought effective quantification into physics, negated the geocentric theory with celestial observations, made a thermometer, and discovered the law of inertia, the formula of simple pendulum period, the formula of falling body, and the understanding of motion recognized as Galileo's theory of relativity. Galileo left behind a large number of thoughtful and beautifully written works, which are the enlightening books of physics.

1. If the short biography of Galileo was not forced by life, who would have made himself full of talent? I thought this sentence was a joke, but I didn't think there was such a person in the world. There has been such a person in Italian history, known as divine mathematician (the blessed mathematician), Tuscan Archimedes (Archimedes of Tuscany), true connoisseur of arts and science (the true connoisseur of science and art), was the first person to introduce effective quantification (effective quantification) into physics so that physics is no longer just a qualitative description as it used to be. He is the counterpart of Aristotelian doctrine, the defender of Copernicus, the standard setter of mathematics, the person hated by Jesuits, the martyr of academic freedom (the sworn enemy of Aristotle, the champion of Copernicus, the standard-bearer of mathematics, the b ê te noire of the Jesuits, or the best-known of all martyrs to academic freedom). These are not things that are not talented or untalented, but are related to the enlightenment of mankind. This man is Galileo (figure 1). Galileo was an all-round genius, but he also made those brilliant achievements in the midst of hardships. There are comments that Galileo might not have become any of these characters (Galileo would have become none of these things had he not to work for a living) had it not been for making a living.

Figure 1. Galileo Galileo (Galileo Galilei,1564.02.15-1642.01.08), founder of modern science, was born in Pisa, Italy, and was originally a Florentine aristocrat with the original surname Bonajuti. Perhaps the correct spelling of Galileo's name should be Galileo de Galilei, but he is called by his first name Galileo and surname Galilei in western literature. Galileo's father, Vincenzo Galilei, is a gifted scholar who specializes in mathematics, music and music theory, and is the author of the Dialogue between Ancient Music and Modern Music. As a father of six, Vincenzo didn't spend much time with Galileo, but that didn't stop his son from becoming the founder of modern science. As Schrodinger's biographer Walter Moore said, the emergence of a genius must first be genetically the genes must be right. Galileo seems to have genius genes, active thinking and full of wisdom, when he was young, he was good at making all kinds of toys and mechanical models, and invented the missing parts to make up for it. Galileo obtained classical education very early (education based on Greek and Latin classical literature). His spare time was devoted to the study of music and painting, and his ability in music and painting was first-rate. Galileo played many musical instruments and wanted to take painting as his career. His criticism of painting was highly recognized by his contemporaries. Vincenzo realized his son's talent and decided to support him to go to college. Galileo went to the University of Pisa in his hometown in 1580 and chose to study medicine according to his father's wishes because he made more money as a doctor. However, Galileo soon developed a strong interest in mathematics and natural philosophy. In 1581, the 17-year-old Galileo looked at the chandelier in the church and saw through the law of the movement of the pendulum. Then the 19-year-old Galileo began to study the hydrostatics that Archimedes had studied. He wrote papers about static balance in water and specific gravity, which attracted the attention of previous mathematicians. Because Galileo completed the study in one fell swoop, he was recommended to Ferdinand I de' Medici, the grand duke of Tuscany, Archduke of Tuscany. Under the patronage of this dignitary, the 25-year-old Galileo got a job teaching mathematics at the University of Pisa in 1589, and his scientific discovery has been unstoppable ever since.

Galileo is regarded as the founder of modern science and modern physics. The word physics originates from the Greek nature (φ σ physics). Physics, as a branch of learning, originated from the works of Aristotle,384-322 BC edited by the later Andronicus of Rhodes (about 60 BC). The corresponding modern physics is Aristotelian physics. Aristotle's tenets of physics and mechanics are basically not supported by experience. Galileo was not the first to challenge Aristotle's creed, but he knew that he had the ability to give the world a solid and new mode of thinking, and he was destined to be the founder of a new school of rational and experimental philosophy. Galileo's new philosophical and intelligent way is to submit each assertion to the experimental test, either directly, or to reveal its possibility and appropriateness. Galileo introduced quantitative expression into physics, and he did a series of experiments to study the authenticity of Aristotle's thesis. Once Aristotle was successfully proved wrong, Galileo would denounce it, which led him to gain more and more opposition from the academic community at that time. The author thinks that Galileo's ability to think about the limit situation, the ability to ignore details, the ability to think abstractly and the ability to express mathematically are the basic guarantees for him to become the founder of modern science.

Galileo gained the image of a prophet when he was alive, and his popularity and the value of his works were recognized by his contemporaries. Since then, anyone in the world who intends to teach elementary physics and has just entered the study of physics should seriously study the works of Galileo, which is the source of physics and physics research methods and philosophy. Some of Galileo's writings are as follows:

La bilancetta (small balance) (1586, Italian)

De motu antiquiora (on the Old works of Sports) (c. 1590, Latin)

Le mecaniche (Mechanics) (c.1600, Italian)

Le operazioni del compasso geometrico et militare (geodesic and military compasses) (1606, Italian)

Sidereus nuncius (Star letter) (1610, Latin)

Discorso intorno alle cose che stanno in su l'acqua, o che in quella si muovono (on objects that float on the surface or move in them) (1612, Italian)

Istoria e dimostrazioni intorno alle macchie solari (description and demonstration of sunspots) (1613, Italian)

Discorso del flusso e reflusso del mare (on Tide) (1616, Italian)

Discorso delle Comete (on Comets) (1619, Italian)

Il Saggiatore (Gold Tester) (1623, Italian)

Dialogo sopra i due massimi sistemi del mondo (dialogue between the two major world systems) (1632, Italian)

Discorsi e Dimostrazioni Matematiche, intorno a due nuove scienze (discussion and Mathematical argumentation of two New Sciences) (1638, Italian)

Lettera a Madama Cristina di Lorena granduchessa di Toscana (letter to the Archduchess of Tuscany) (1615, Italian. This book is intended to defend Copernican doctrine)

Italy published Le opere di Galileo Galilei (edizione nazionale), the Galileo Collection (national edition), in 20 thick volumes between 1890 and 1909. A person's work has a national edition, which can be regarded as the highest honor.

2. Galileo's scientific achievement Galileo was the founder of modern science, especially physics, which was said by Einstein in 1954 (Albert Einstein, Ideas and opinions, Crown Publishers (1954)). As can be seen from the works left by Galileo, Galileo introduced us a systematic research method of physics and introduced quantification into the expression of the laws of nature. The simple pendulum formula, the law of inertia and the falling body formula are all the preliminary contents and the most basic contents of physics, so their connotation can only be realized through careful taste after having profound physical knowledge.

2a) the cycle formula of a simple pendulum Galileo's father chose a medical major for him at the University of Pisa, which was ridiculed as a rare major that Galileo was not suitable to study. Galileo was not very active in studying medicine, but he was so interested in mathematics that Galileo's father asked his teacher to teach mathematics so much as to forget it. During these awkward days (~ 1581), Galileo became interested in the chandelier in the cathedral near the University of Pisa. The chandelier swings back and forth (figure 2), which is the phenomenon that we later modeled with a simple pendulum (pendulum) in our elementary physics textbooks. It takes about the same time for the chandelier to swing back and forth (subject to the movement turning two times in succession on one side. Because of air resistance and other reasons, the swing amplitude is actually decreasing all the time, but this does not hinder the conclusion that the simple pendulum motion is periodic. Think carefully about why), so guess that the pendulum is a periodic motion. Galileo found that although the amount of oil in the chandelier varied, the swing period of the chandelier with a fixed height was isochronous, and he concluded that the period of the simple pendulum had nothing to do with the weight of the pendulum (pendulum, pendulum). If the oil in the chandelier burns dry, it will be put down from the church dome to replenish the oil, giving it a chance to observe the movement of a simple pendulum with increasing length. Galileo found that the longer the pendulum, the longer the swing period. Note that there was no second-order time measurement (the sundial could only roughly divide the hours), and Galileo used his own pulse to calibrate the period in which the chandelier swayed. The longer the pendulum rope, the longer the swing period, what kind of law does it follow? The relation given by Galileo is that the square of the period is proportional to the length of the pendulum (note that y=kx2 is the relation of type). In fact, Galileo's report on the study of a simple pendulum appeared in a letter to a friend in November 1602. Of course, based on the knowledge of modern physics, we know that the simple pendulum is approximately monotone vibration only in the case of small amplitude. According to Newtonian mechanics, the equation of motion of the pendulum is.

Galileo instructed his son to make a pendulum clock, but without success. The first pendulum clock was made by the Dutchman Christiaan Huygens,1629-1695 in 1656, and the post-pendulum clock was the most accurate device for measuring human time until 1930. This is later.

Figure 2. "Galileo's chandelier" 2b) thermometer and falling body movement law in Pisa church is a well-known natural phenomenon, how to express and quantify the degree of hot and cold is a long-standing demand. The thermometer (thermoscope, heat + watch) can be regarded as the predecessor of the thermometer (thermometer, heat + quantity), which can show the change of temperature, but it is not quantified and there is no specific reading-the premise that the thermometer has a reading is to have a temperature scale (temperature scale), which requires thermodynamics and other physics, which beginners in thermodynamics should pay special attention to. A simple thermometer can be a glass bubble supported by a slender tube, and the lower end of the slender tube is buried in water. The change of temperature causes the change of air pressure in the glass bubble, resulting in the rise and fall of the water column in the observable slender tube. Galileo is said to have realized the principle of making a thermometer in 1593 and mentioned to a friend that he invented the thermometer in 1606. Of course, the fact that the properties (volume, pressure) of the gas or liquid on which the thermometer is based varies with temperature has been recognized since ancient Greece. In fact, the thermometer has been widely used in the Galileo era, and its invention and improvement is a long process of physics. Interested readers can refer to the special works, which is the entry point of thermodynamics.

However, Galileo is Galileo, and his achievement in the thermometer is not as simple as qualitatively sensing temperature changes. Galileo's thermometer is a cylindrical sealed container with solutions whose density varies significantly with temperature (such as water plus alcohol and some lipids. There may also be layering of different density substances due to gravity and chemical properties), as well as several suspensions with different (average) densities but also near the solution density. The suspension is a hollow glass bubble with a metal counterweight to adjust its average density (figure 3). In this way, when the temperature changes, the density (and its distribution) of the liquid in the glass column will change, and the suspension shape of the suspension parts (which parts will be suspended in the liquid and where they will be suspended) will change accordingly. From this, the change of temperature can be judged qualitatively. Remember, however, that Archimedes' buoyancy principle is used here, and Galileo is the thinker who studied Archimedes' theory. Galileo noticed (for example, the following paragraph was arranged by the author and forgot where to read it) that when a liquid with a given density is given, the suspension with a higher density than the liquid will sink (initially in the form of accelerated motion, if the distance is large enough to eventually fall at a uniform speed due to the viscous force of the liquid), the suspension with a lower density than the liquid remains floating on the liquid surface, which can be understood as zero falling (plus) velocity. Now, imagine that the density of the liquid is large enough at the beginning that all the suspended parts float on the liquid surface, that is, the falling acceleration is zero. When the density of the liquid is reduced, some suspensions sink, but out of sync, and some continue to float on the liquid surface. If you further reduce the density of the liquid and restart the experiment, the suspended parts that can sink will fall faster, and some suspended parts that were floating on the liquid surface can also sink. At least for those suspended parts that can just sink, it makes sense to be able to catch up with heavier (heavier) companions in the process of falling. So, suppose we keep reducing the density of the liquid, then there have always been less dense suspensions that add the falling process to the liquid, and the difference between suspensions with different specific gravity is getting smaller and smaller (isn't the difference caused by the density of the liquid? Isn't the acceleration of all suspending parts in the initial state of zero? ). So, in the limit case, what will happen when the density of the liquid is 00:00, that is, in a vacuum? The only reasonable answer is that all objects (regardless of whether they have the same weight or specific gravity) fall synchronously in the gravity field. This conclusion is shown in Einstein's general theory of relativity that Einstein modified the definition of inertial motion: the external force other than gravity is 00:00 and the motion of the body is inertial motion.

Galileo realized that falling bodies are synchronous and have nothing to do with weight (mass). This contradicts Aristotle's creed of physics and unabstract observations in daily life, and how to convince contemporaries is a very difficult task. Galileo is said to have climbed the leaning tower of Pisa to demonstrate that iron balls of different weights fall synchronously. However, this anecdote can only be seen in Galileo's follower Vincenzo Viviani's biography of Galileo, which Galileo himself did not mention. In modern times, there are a variety of so-called experiments to verify the synchronous whereabouts, which belong to physical exploration other than serious physics. I would like to stress again that there is no experiment that can verify the synchronization of whereabouts. Objects with different weights (masses) fall synchronously in the gravitational field, or expressed at a higher level, the motion of the object in the pure gravitational field is inertial, which is concluded by abstract power. Physics is not an introduction without understanding the power of abstraction.

In addition, Galileo's thinking about thermometers led to the concept of thermal atomism, which was found in his 1623 pamphlet Il saggiatore.

Figure 3. Galileo's thermometer (contemporary replica) 2c) the discovery of the law of inertia and the formula of falling body motion Galileo put another slope on the opposite side of one slope (figure 4), and he found that a small ball rolling down the left slope, it will climb to about the same height on the opposite slope, but the elevation of the opposite slope has little effect. If the slope is made smooth enough, the ball can reach its initial height on the opposite slope. As an ideal state (zero friction), it is reasonable to think that the ball will return to the height at which it fell, regardless of the elevation of the opposite slope. So, as a limit case, what should the ball do when the elevation of the opposite slope is zero, that is, there is no slope for the ball to climb? It tried to reach the height of its initial fall, but failed to achieve it at all. As a result, the ball can only move forward. Therefore, it can be concluded that the body with zero resultant force of external force keeps its original state of motion unchanged. Later, this became the first of the three laws of Newtonian mechanics, the law of inertia. It was Kepler (Johannes Kepler,1571-1630) who called the trend of objects against changes in motion inertia. Please note that mass, inertia and inertial mass are exactly the same thing (see my book, Physics).

Figure 4. The relative slope and the motion of the ball on it, how to study the motion of the falling body quantitatively? We know that an object falling from a height of 20 meters takes about 2 seconds to reach the ground. In the Galileo era, there were no clocks and high-speed photography. How can this be studied? Galileo found that when a ball rolled down a slope, if the elevation of the slope was small enough, it would fall long enough to make meaningful measurements. In about 1604, Galileo reduced the elevation of a wooden slope to as little as 17 °(figure 5). Galileo installed an adjustable bell on the slope, and when the metal ball rolled over the bell, it would make the bell ring to announce the ball's passing. Galileo adjusted the position of the bell so that the sound of the bell was (approximately) evenly spaced, measuring the distance between the bells (for the first bell, it was the distance from where the ball began to fall, which was generally chosen as the top of the slope). It was found that the ratio of spacing was about 1V 3V 5V 7. (there is no precise measurement here. Accurate measurement and computer simulation can lose all the simple rules. Physics is built with the mind. This means that with the increase of the unit of time note [1], the distance over which the ball rolls is 12 / 22 / 32 / 42. So the law of falling body is obtained.

. This part can be found in Galileo's Dialogue on two New Sciences. When we have calculus, we know that the formula of falling body is h = 2. At2. For a free fall, h = gravity GT2, g is the gravitational acceleration. Notice that this is the relationship of type y=kx2 again. In fact, the French medieval scholar Nicole Oresme,1320~1325? -1382) the distance-time square law of uniformly accelerated motion has been obtained before.

Figure 5. Galileo's facility for the study of falling motion (2d) the telescope and the two glasses placed before and after Xingxin have the effect of imaging distant objects. In 1608, Dutch optician Hans Lippershey,1570-1619 applied for a patent for the telescope. In 1609, when Galileo heard the news, he sharpened his own mirror and made a telescope, which he called perspicillum in Star Xin, with magnification of 8x and 10x, and later up to 20x (figure 6). In 1611, the Greek mathematician Giovanni Demisiani coined the word telescope based on the Greek words τ λ ε (tele, far) and σ κ π ε v (scopein, see). Using a simple homemade telescope, Galileo claimed that he could see more than ten times more stars than the naked eye could see. Galileo completed his observation of the moon's surface, discovered craters and mountains, speculated on the height of the mountains, and observed four moons of Jupiter. All these are described in detail in the book Xingxin. Sidereus Nuncius has an English translation of Starry messenger, according to which it is translated as "Interstellar Messenger". Some international scholars have long pointed out that the correct English translation should be the news from starry message-- from the stars, and foolishly thought that it would be more accurate to translate it into "Xingxin". Galileo observed the phase (phase of Venus) annotation of Venus at the end of 1610, and the results can be found in the description and demonstration of solar black spots published in 1613 (figure 7).

Figure 6. Galileo's used telescope stored in the Galileo Museum in Florence

Figure 7. Galileo's phase diagram of Venus Galileo's telescope observation had a great impact on Western civilization. The discovery of craters and mountains on the lunar surface shows that the moon is not a perfect sphere, which contradicts an important belief of the Western Church that the planet in heaven is a perfect ball and the orbit of the stars is a perfect circle. The observation of the phase of Venus shows that Venus does not revolve around the earth, and the discovery of Jupiter's four moons shows that Jupiter can also be the center of rotation, which coincides with Copernicus's heliocentric theory and the theory that there are many suns in the sky. That is to say, the earth is not the center of the universe, nor is the sun the center of the universe. There are many places in the universe that seem to be the center of rotation. These contents are in serious conflict with Western beliefs.

3. Galileo's dialogue work Galileo is the initial literature of modern science, and its reference value is inestimable for people who want to be physics teachers and physicists. The author's affection for Galileo's works is that it is too late to meet each other, and he feels sorry for seeing him too late and understanding too little. Limited to space, here is only a brief introduction to his two long dialogic works.

3A) Dialogo sopra i Due Massimi Sistemi del Mondo on the dialogue between the two major world systems was written in Italian in 1632, which is a major event in the academic history of Europe, as previous academic works were written in Latin. Later, the book was translated into a Latin text called Systema cosmicum (Universe system) in 1635 and Dialogue Concerning the Two Chief World Systems in English, which has a wide influence in the world. This book compares the previous Claudius Ptolemaeus,~100-170cosmic system, the geocentric theory, with the new Nicolaus Copernicus,1473-1543 cosmic system, the heliocentric theory. The title of the book at the time of writing was "Dialogue about Tides". Those who study physics understand that it is because the fluctuation of water on the earth makes people feel the gravity (field) from the moon, and it also makes people wonder whether the earth moves or not. The structure of the book is set to be a record of conversations between three people over four days. The three protagonists in the dialogue are named Salviati, a wise man who speaks for Galileo; Sagredo, who has some culture but does not take a stand; and Simplicio, who is a proponent of Ptolemy and Aristotle, a scholar of the Aristotelian or carefree school (peripatetic philosopher). Each of the three men had archetypes. The first two surnames came from Galileo's acquaintances, while the third surname, Simplicio, according to Galileo, was taken from the famous Aristotelian scholar Simplicius. However, the Italian meaning of Simplicio is the meaning of the simple-minded, and the irony is beyond words. Simplicio's literal meaning and words in the dialogue make the dialogue seem to be a book that attacks Aristotle's geocentric theory while defending Copernicus's heliocentric theory. The book was published in 1632, and only in 1633, Galileo was suspected of being a heretic by the Vatican, so he was interrogated by a church magistrate and was placed under house arrest, and the book was not lifted until 1835. By the way, this book is not only about the world system, but also about what is good science and the magnetic study of Gilbert (William Gilbert,1544-1603) Note [3], and so on.

With the help of Salviati, Galileo refutes Aristotle's cosmic system, such as his argument that there is a change under the moon but no change in the world outside the moon, based on the observed nova explosions and the existence of moving sunspots in 1572 and 1604. To explain why the earth is moving but humans can't feel it, Galileo introduced the famous mechanical experiment in a large cabin, a landmark thought experiment, which was later recognized as Galileo's theory of relativity in 1909 (see below). In addition, Galileo's argument against the old cosmic system includes providing evidence for the existence of the phase of Venus, which cannot be explained by the Ptolemaic system, and the movement of sunspots, which is extremely complex to be explained by the Ptolemaic system. In fact, the phase of Venus and the existence of sunspots are not found in the previous theory of the universe, and it must be wrong to prove that the earth is still. Galileo used tides to prove that the earth was moving. Of course, it is not correct to use the mechanics of tidal phenomena to prove that the earth is not still. Einstein later said that Galileo would not have thought his argument was correct if he had not been short-tempered.

The greatest value of the book "Dialogue between the two main World Systems" lies in the so-called Galileo theory of relativity. With regard to the relative movement, Galileo's argument is that although a large ship has traveled a long way, we can still identify the position of the food bag on board. We are concerned about the position of the food pocket relative to the ship, and it has no movement relative to the ship. Moreover, if nature can allow such large celestial bodies outside the earth to move at such a great speed, why let the earth go alone? If the Earth, which is considered to be the only immobile being, is removed from the image of the entire universe, what happens next to the so-called motion? Note [4] Galileo described in detail what happened in a closed cabin under the title of "an experiment that shows that all those experiments used to oppose the earth's motion are completely invalid". Galileo wrote: "in order to finally show that the experiment (revealing uniform motion) is completely ineffective, I think this is a good way to show you an easy way to verify." Put you and some friends in the main cabin under the deck of a big ship, take some flies, some butterflies, and other small animals that can fly. Bring a large bowl of water with fish in it; hang a bottle and let the water drop into the wide-mouth container below. When the ship is still, please observe carefully that the small animals are flying around at the same speed in the cabin. It doesn't matter in which direction the fish swim; the water droplets will fall into the container directly below; if you throw something at your friend, you don't have to work harder in this direction, save effort in that direction, and throw it at the same distance; take off with your feet, and you will jump as far in different directions. When you have made these observations carefully (there is no doubt that this is what things should be like when the ship is still), let the ship move forward at any speed, as long as the speed is uniform rather than fast and slow. You will see that the aforementioned effect will not change at all, and you will not be able to tell whether the ship is going or stopping from these observations. Take off, you will cross the same distance as before, not far towards the stern and closer to the bow, even though the ship is moving at high speed, the board under your feet (when you jump to the stern) goes straight in the opposite direction while you are floating in the air. If you throw something at your partner on the other side, you don't have to push extra hard because he is in the direction of the bow or stern. The droplets will fall into the container directly below instead of drifting to the stern, as before, although the ship darted forward a lot during the fall. The fish in the bowl swim forward as easily as they swim back, and swim as freely to the fish food at the edge of the bowl. Finally, butterflies and flies will continue to fly around instead of gathering at the stern, as if they were too tired to keep up with the boat because they had to stay in the air and travel long distances. Moreover, if smoke rises from the light of something, the smoke will rise straight up to form a small cloud, standing still, neither forward nor backward. The reason for these effects is that the motion of the ship is shared by all the objects it contains, including air. That's why I said you should stay below deck; if you were in an open space and the air could not keep up with the ship's journey, the effect we were talking about would be somewhat different. There is no doubt that smoke lags far behind the air itself, and flies and butterflies are trapped by the air, so they cannot keep up with the ship if they are far away from the ship. But by keeping them close to the ship, they can easily follow, for the ship, with the air around it, is a whole. For similar reasons, when we ride a horse, we will see some flies and cow tabanus always follow our horses and fly from one part of the horse to the other. " One of the fundamental ideas that Galileo is trying to explain here is: "No mechanical experiment can be used to judge whether a ship is at rest or at any uniform speed." It can be inferred from this that people are not aware of the movement of the earth. Later, in 1909, Einstein regarded the idea of Galileo as the theory of relativity, which was called Galileo's theory of relativity. If expressed in a formula, I think it can be understood as follows. If the law of the universe can be described by the equation f (r, t; λ) = 0, Galileo's theory of relativity requires that the function f satisfies the following conditions: "if f (r, t; λ) = 0, then for any constant v, there must be f (r+vt, t; λ) = 0. Galileo space-time is transformed into t → t → x → x x → y → z. For the theory of relativity, please refer to my book Relativity-Juvenile Edition.

3B) the dialogue between the two new sciences in 1638 is said to be because the young Viviani's door-to-door mentor rekindled Galileo's enthusiasm for science under house arrest, and he wrote Discorsi e Dimostrazioni Matematiche intorno a Due Nuove Scienze in Italian. The title of the book literally means "discussion and mathematical argumentation of two new sciences", but the English translation is called Dialogue Concerning Two New Sciences, and according to the Chinese translation of the English version, it becomes the annotation of "Dialogue about two new sciences" [5]. In this way, there are two dialogic works of Galileo in English and Chinese academic circles. Among the popular introductions about Galileo's achievements and ideas, the contents of these two books are often confused and make people laugh or cry.

The theme of the book "Dialogue between two New Sciences" is about the structure of matter and the law of motion. The structure of the book is still a dialogue between Salviati, Sagredo and Simplicio, divided into four days. The first day revolves around the problem of solid anti-fracture (resistenza). Of course, the driving force of learning comes mostly from the demand of application, and the problem of solid fracture comes from the demand of shipbuilding industry. What attracts attention is the suggestion of building ships of iron based on the understanding of buoyancy in the book. The next day was about the cause of material union. In modern terms, this is the science of solid physics, material mechanics and structural mechanics, and the so-called first new science in this book can be understood as the bud of these disciplines. Galileo noticed that the tensile strength of the material was better than that of bending, and both Aristotle and Archimedes had analyzed the related problems, but Archimedes had to be considered in terms of rigor. What attracts the author's attention is that as far as the scientific method is concerned, Galileo tells us that things can be examined either in an abstract form that is divorced from matter or in a concrete form associated with things. Today we can say that, in fact, both are necessary. The third day of discussion is about motion, including uniform motion and natural acceleration, and the fourth day is about projectile motion. In contemporary terms, this involves kinematics, dynamics, gravity, ballistics and so on. Few people did real research on sports before Galileo. The value of this book is that it describes the budding of modern physics, which is too important for the cultivation of physicists. How many people who know nothing about physics and physical research methods have unconsciously become physicists. By the way, Galileo's Toucher contains more ideas on how to do science, which can be regarded as Galileo's scientific manifesto.

4. Adhering to the theory of ground motion E pur si mouve is still moving. It is a famous maxim in the history of human civilization. It is regarded as an example declaration of upholding truth in defiance of evil forces. Galileo is said to have said this in 1633 when he was asked to retract the idea that the earth moves around the sun. However, this sentence is likely to be falsely entrusted by future generations. The motto much more likely to be apocryphal). The so-called Galileo said this sentence, first appeared in 1757 Italian Giuseppe Baretti's English book The Italian library (Italian library) "This is the celebrated Galileo, who was in the Inquistion for six years, and put to the torture, for saying, that the Earth moved. The moment he was set at liberty, he looked up to the sky and down to the ground, and, stamping with his foot, in contemplative mood, said, Eppur si mouve Notes [6]; that is, still it moves, meaning the earth." The exact word "E pur si muove" was first found in 1911 in an oil painting titled Galileo in prison (Galileo in prison) believed to have been completed in 1643 or 1645 (figure 8). Later, some art historians discovered a painting of the same name and judged it to be a work of the 19th century. However, in any case, Galileo found a lot of evidence of the theory of ground motion, made a detailed analysis, and stuck to his point of view in the face of pressure from the Vatican. Galileo initiated modern science, brought revival to a branch of human civilization, and brought great progress of human civilization based on science and technology. As a physicist, the author is full of admiration for Galileo Galileo. Of course, Galileo has his limitations. Galileo could not accept the concept of distorted circle, nor did he accept elliptical astronomy, that is, the astronomy in which Kepler's planets have elliptical orbits. Distorted circle, refers to the ellipsis, the original meaning of ellipsis is almost, a little ecliptic. Kepler's first and second laws of planetary motion were published in 1609, and it was 33 years before Galileo died. What if Galileo accepted Kepler's elliptical astronomy? (I don't know what he will find.

Figure 8. Galileo in Prison by Jules van Belle Italy is the root of the Roman Empire and there is a supranational center of ecclesiastical influence in the country. As far as heliocentric theory is concerned, Copernicus, the Polish who proposed the heliocentric theory, died in 1543, and the three laws of the motion of the planets around the sun were published by the German Kepler in 1609 (the first law and the second law) and 1619 (the third law). However, in support of heliocentric notes [7], Galileo was placed under house arrest in 1633 after he published the Dialogue on two Major World Systems in 1632. It is inevitable that modern physics was born in Italy, a Greek neighbor. Schrodinger once said, what is science? Science is thinking in a Greek way. But it is ironic to think that Italy at that time was undoubtedly the most capable place not to welcome science. Or is it instructive?

5. Superfluous words in recent years, after studying the experiences and achievements of some giants of mathematics and physics, the author thinks that excellent characters are born first, and good education is secondary. The starting line of a child is the state of his parents at birth, and the highest level of his achievements in this life is a foregone conclusion, whether the ceiling is high or low, it is there. The rest is that he wants to do well in his life, and this is still a multi-parameter function, with a lot of accidental factors. It may be more important for children to find their talents and hobbies and to live a relaxed or nervous life with no regrets. Galileo was born a versatile and intelligent man, but his father was able to let him choose a rare subject in college that he was not fit to study, medicine, and there are rare anecdotes in the world. Fortunately, Galileo's genius could not be turned away at that detour, and a glance at Euclid's "geometry" was enough to bring him back to his mission.

Galileo is undoubtedly a genius, and his superb thinking ability, practical ability and expression ability are reflected in many aspects, such as doing science and playing art, which are obviously not acquired through ability education. Of course, acquired education, which comes from the small environment of the family and the big environment of the society, also has a decisive influence on a person's growth. Galileo's writings are famous for dialogs. If you notice that Galileo's father Vincenzo wrote Dialogo della musica antica e della moderna (Dialogue between Ancient and Modern Music) in 1581, you can see why Galileo loved to write dialogues. At that time, the Italian dialogue text (Il dialogo) was traditional.

Galileo's work is the source of physics. It will teach you how to do physics research from scratch and how to be a good physics educator. The author bought an Italian-Chinese Dictionary (Dizionario Italiano-Cinese) around 1988, but never thought of reading Galileo seriously. I really regret it now. Galileo was the founder of modern physics. Why did I write so little about him in my basic physics education? It's illogical.

reference

1.Antonio Favaro (ed.), Le Opere di Galileo Galilei (Galileo Collection), Barbera (1909).

2. John Elliot Drinkwater Bethune,The Life of Galileo Galilei, Bibliobazaar (2008).

3.Stillman Drake, Galileo: A very short introduction, Oxford (1980).

4. Mario Livio, Galileo and the Science deniers, Simon & Schuster (2020)

5.Matteo Valleriani, Galileo Engineer, Springer (2010).

6. Mario Livio, Did Galileo Truly Say, 'And Yet It Moves'? A Modern Detective Story, Scientific American,May, 2020

Annotation

[1] A unit of time is an exact, identical interval, counted in integers. If you think that the units of time are not strictly equal, the premise is that you have smaller units of time.

[2] Phase, phase, means appearance. What the moon and Venus look like from the earth is of course related to the relative position of the sun, the earth and the star, but translating phase into phase and phase is still a big mistake! There is nothing literal about location in Phase. When talking about phase of matter, phase, phase diagram, phase diagram, it will make people think that the phase here has nothing to do with the phase when in fact they are the same thing!

[3] the British scholar coined the word electricus in 1600.

[4] this extreme, abstract form of argument will be used again and again by Galileo. Foolishly thought that this is the most meaningful research method.

[5] if you have to read the translation, it is better to choose the translation according to the original. If the translation still needs to change hands, it is even more extravagant to be faithful to the author's original meaning.

[6] there have always been two ways to write E pur si mouve and Eppur si mouve.

[7] heliocentric theory is also wrong. The author thinks that from the point of view of the theory of relativity, the universe is unintentional.

This paper is the first chapter of "majestic as one" by Cao Zexian.

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