Some theories about Albert Einstein!

Foundation of Special Relativity: As early as 16 years old, Einstein learned from books that light is an electromagnetic wave moving at a very fast speed, and he had an idea that if a person moves at the speed of light, what kind of a picture of the world will he see? He would not see light moving forward, but only an electromagnetic field oscillating but stagnant in space. Could such a thing happen? In connection with this, he was very interested in exploring the question of the so-called Ether in relation to light waves. The term Ether originated in Greece to represent the basic elements that make up objects in the heavens, and was first introduced to science by Descartes in the 17th century as a medium for the propagation of light. Later, Huygens further developed the doctrine of Ether, arguing that the medium that carries light waves is Ether, which should fill all of space, including the vacuum, and be able to permeate ordinary matter. In contrast to Huygens' view, Newton proposed the particle theory of light. Newton believed that a luminous body emitted a stream of particulate particles moving in a straight line, and that vision was caused by the impact of the stream on the retina. 18th century Newton's particulate theory prevailed, but in the 19th century it was the fluctuating theory that prevailed, and the etheric theory was greatly developed as a result. At that time, it was believed that the propagation of waves depended on the medium, because light could propagate in a vacuum, and the medium for propagating light waves was the Ether that filled the entire space, also called the light Ether. At the same time, electromagnetism has been vigorously developed, after Maxwell, Hertz and other people's efforts to form a mature kinetic theory of electromagnetic phenomena - electrodynamics, and from the theoretical and practical aspects of light and electromagnetic phenomena unified, that light is a certain frequency range of electromagnetic waves, so that the fluctuation theory of light and electromagnetic theory Unification. Ether is not only the carrier of light waves, but also becomes the carrier of electromagnetic fields. Until the end of the 19th century, attempts were made to find the Ether, yet the Ether was never found in experiments. Electrodynamics, however, encountered a major problem in that it was inconsistent with the principle of relativity, which was followed by Newtonian mechanics. Ideas about the principle of relativity have been around since the time of Galileo and Newton. The development of electromagnetism was also initially incorporated into the framework of Newtonian mechanics, but difficulties were encountered in explaining electromagnetic processes in moving objects. According to Maxwell's theory, the speed of an electromagnetic wave in a vacuum, i.e. the speed of light, is a constant quantity, however, according to the principle of addition of speed in Newtonian mechanics, the speed of light varies in different inertial systems, which raises the question: is the principle of relativity, which applies to mechanics, applicable to electromagnetism? For example, there are two cars, one approaching you and one driving away. You see the lights of the former car approaching you and the lights of the latter car moving away. According to Maxwell's theory, both lights have the same speed, and the speed of the cars plays no role in this. But according to Galileo's theory, the two measurements are different. The car coming toward you will emit light that is accelerated, i.e., the speed of light from the car in front = speed of light + speed of the car; and the speed of light from the car moving away is slower because the speed of light from the car behind = speed of light - speed of the car. Maxwell's and Galileo's statements about speed clearly contradict each other. How do we resolve this disagreement? Theoretical physics reached its peak in the 19th century, but there was a great crisis implied. The discovery of Neptune showed the incomparable theoretical power of Newtonian mechanics, and the unification of electromagnetism and mechanics made physics show a form of completeness, and was known as "a stately and majestic architectural system and a beautiful temple of stirring emotions". In people's minds, classical physics has reached a degree of near-perfection. Planck, the famous German physicist, said to his teacher when he was young that he wanted to devote himself to theoretical physics, and the teacher advised him, "Young man, physics is a finished science, there will not be much more development, and it is too bad to dedicate one's life to this discipline." Einstein seemed to be the man who would build the edifice of a brand new physics. During his days at the Bern Patent Office, Einstein paid extensive attention to the cutting-edge developments in the world of physics, thought y on many issues, and developed his own unique insights. During his ten years of exploration, Einstein carefully studied Maxwell's theory of electromagnetism, especially electrodynamics as developed and elaborated by Hertz and Lorentz. Einstein was convinced that the electromagnetic theory was completely correct, but there was one issue that disturbed him, and that was the existence of an absolute frame of reference, the Ether. He read many works and found that all attempts to prove the existence of the Ether failed. After researching Einstein found that the Ether had no practical significance in Lorentz's theory except as an absolute frame of reference and a charge to the electromagnetic field. So he thought: Ether absolute frame of reference is necessary? Must the electromagnetic field have a load? Einstein liked to read philosophical works and absorbed ideas from philosophy, and he believed in the unity of the world and logical consistency. The principle of relativity had been widely proved in mechanics, but could not be established in electrodynamics. Einstein was skeptical about the logical inconsistency of these two theoretical systems of physics. He argued that the principle of relativity should hold universally, and therefore electromagnetic theory should have the same form for each inertial system, but here the question of the speed of light arose. Whether the speed of light was an invariant or variable quantity became the primary question of whether the principle of relativity was universally valid. Physicists at that time generally believed in the Ether, that is, in the existence of an absolute frame of reference, which was influenced by Newton's conception of absolute space.At the end of the 19th century, Mach criticized Newton's conception of absolute space and time in his book "Developing Mechanics", which left a deep impression on Einstein. One day in May 1905, Einstein discussed this problem, which had been explored for ten years, with a friend, Besso, who elaborated his views in accordance with Machism, and the two discussed it for a long time. Suddenly, Einstein realized something, and after repeated thoughts at home, he finally figured out the problem. The next day, he came back to Besso's house and said: Thank you, my problem is solved. It turned out that Einstein figured out one thing: there is no absolute definition of time, time and the speed of light signals have an inseparable link. He found the key to the lock, and after five weeks of hard work, Einstein presented the theory of special relativity to the people. On June 30, 1905, the German Annals of Physics accepted Einstein's paper, "On the Electrodynamics of Moving Bodies," for publication in the September issue of the same year. This paper was the first article on the theory of special relativity, and it contained the basic ideas and essential elements of special relativity. Special relativity is based on two principles: the principle of relativity and the principle of invariance of the speed of light. Einstein's starting point for solving the problem was his firm belief in the principle of relativity. Galileo first articulated the idea of the principle of relativity, but he did not give a clear definition of time and space. Newton also talked about the idea of relativity when he established the system of mechanics, but then defined absolute space, absolute time and absolute motion; he was contradictory on this issue. And Einstein greatly developed the principle of relativity, in his view, there is no absolute static space, the same does not exist in the absolute same time, all time and space are associated with moving objects. For any frame of reference and coordinate system, there is only space and time belonging to this frame of reference and coordinate system. For all inertial systems, the physical laws expressed by applying the space and time of that frame of reference, which all have the same form, is the principle of relativity, strictly speaking, in the narrow sense. In this essay, Einstein did not discuss much the basis for making the invariance of the speed of light a fundamental principle; he proposed that the invariance of the speed of light was a bold assumption, made from the requirements of electromagnetic theory and the principle of relativity. This article is the result of Einstein's many years of thinking about the problem of Ether and electrodynamics, and he took this point of relativity of simultaneity as a breakthrough to establish a completely new theory of time and space and to give the electrodynamics of the moving body a complete form on the basis of the new theory of space and time, where the Ether is no longer necessary, and the Etheric Drift is non-existent. What is the relativity of simultaneity? How do we know that two events in different places are simultaneous? Generally, we confirm this by signaling. In order to know the simultaneity of events in different places we would have to know the speed at which the signal is traveling, but how do we measure this speed? We must measure the spatial distance between the two places and the time it takes for the signal to travel. The measurement of the spatial distance is easy, the trouble lies in the measurement of the time, we must assume that there is a clock at each of the two places that has been aligned, and from the readings of the two clocks we can tell how long it took for the signal to travel. But how do we know that the clocks in opposite places are aligned? The answer is that a signal is still needed. Can this signal align the clocks? If we follow the previous line of thought, it requires a new signal, so that infinitely backwards, the simultaneity of the foreign places cannot actually be confirmed. One thing is clear though, simultaneity must be linked to a signal, otherwise it would be meaningless to say that the two things happened at the same time. A light signal may be the most appropriate signal to use against a clock, but the speed of light is non-infinite, which gives rise to the novel conclusion that two things that are simultaneous for a stationary observer are not simultaneous for a moving observer. Let's imagine a train traveling at a high speed, which is close to the speed of light. As the train passes through the platform, A is standing on the platform, and two flashes of lightning flash before A's eyes, one at the front end of the train and one at the rear end, and leave traces at the ends of the train and at the corresponding parts of the platform, and it is concluded by the measurements, that the distance between A and the two ends of the train is equal, and that A saw both flashes of lightning at the same time. To A, therefore, the two light signals received traveled the same distance in the same interval of time and reached his position at the same time, and the two events must have occurred at the same time; they were simultaneous. But for B, who is in the center of the train interior, the situation is different, because B is moving with the high-speed train, and therefore he will first intercept the front signal propagating toward him, and then receive the light signal coming from the back end. For B, these two events are not simultaneous. That is, simultaneity is not absolute but depends on the state of motion of the observer. This conclusion negates the absolute time and absolute space framework that is cited as the basis of Newtonian mechanics. The theory of relativity holds that the speed of light is invariant in all inertial frames of reference and that it is the maximum speed at which an object can move. As a result of relativistic effects, the length of moving objects becomes shorter and the time of moving objects expands. However, due to the problems encountered in everyday life, the speeds of motion are very low (compared to the speed of light) and the relativistic effect is not seen. Einstein established relativistic mechanics based on a radical change in the view of space and time, stating that mass increases with speed and tends to infinity as the speed approaches the speed of light. He also gave the famous mass-energy relationship equation: E=mc^2, which played a guiding role in the later development of atomic energy. Establishment of the General Theory of Relativity: In 1905, Einstein published his first article on the theory of special relativity, which did not immediately cause a great deal of reaction. But Planck, a German authority on physics, noticed his article and considered Einstein's work comparable to Copernicus's. It was due to Planck's impetus that relativity soon became a subject of study and discussion, and Einstein received attention from the academic community. In 1907, Einstein followed the advice of a friend and submitted the famous paper to apply for a supernumerary lectureship at the Bundestechnische Universit?t (BTH), but the response was that the paper was incomprehensible. Although Einstein was already well known in the German physics community, he could not get a university teaching position in Switzerland, and many prestigious people began to fight for him. 1908, Einstein finally got the position of supernumerary lecturer and became an associate professor the following year. 1912, Einstein became a professor, and in 1913, at the invitation of Planck, he served as the director of the newly established Kaiser Wilhelm Institute of Physics and a professor at the University of Berlin. Institute and professor at the University of Berlin. During this period, Einstein was considering the generalization of the established theory of relativity, and for him there were two problems that disturbed him. The first was the problem of gravity; special relativity was correct for the physical laws of mechanics, thermodynamics and electrodynamics, but it could not explain gravity. Newton's theory of gravity was superdistant, and the gravitational action between two bodies was transmitted instantaneously, i.e., at infinity, which conflicted with the view of fields and the limiting speed of light on which the theory of relativity was based. The second is the problem of non-inertial systems; special relativity, like the previous laws of physics, applies only to inertial systems. But in fact it is difficult to find true inertial systems. Logically, all laws of nature should not be limited to inertial systems, but must consider non-inertial systems. Special relativity is difficult to explain the so-called twinning feint, which says that there are a pair of twins, brother in a spaceship doing cosmic voyage at a speed close to the speed of light, according to the relativistic effect, high-speed movement of the clock slows down, and by the time the older brother comes back, the younger brother has become very old, because the earth has already experienced a few decades. And according to the principle of relativity, the spaceship moves at a high speed relative to the Earth, and the Earth moves at a high speed relative to the spaceship, and the younger brother looks at the older brother becoming younger, and the older brother looks at the younger brother who should be younger as well. The question is simply unanswerable. In fact, special relativity deals only with uniform linear motion, and the brother has to go through a process of variable-speed motion to come back, which relativity cannot deal with. While people were busy trying to understand relative special relativity, Einstein was embracing the completion of general relativity. In 1907, Einstein wrote a long article on special relativity, "On the Principle of Relativity and the Conclusions Drawing Therefrom," in which Einstein mentioned the equivalence principle for the first time, and since then, Einstein's ideas on the equivalence principle have evolved. He took the natural law that inertial mass and gravitational mass are proportional to each other as the basis of the equivalence principle, and proposed that a uniform gravitational field in an infinitely small volume can completely replace the frame of reference for accelerated motion. Einstein also put forward the closed box argument: in a closed box in the observer, no matter what method can not determine whether he is at rest in a gravitational field, or in the absence of a gravitational field but in the accelerated motion of the space, this is the explanation of the principle of equivalence of the most commonly used argument, and inertial mass and gravitational mass is equal to the principle of equivalence of a natural corollary. In November 1915, Einstein presented four papers to the Prussian Academy of Sciences, in which he presented new ideas, proved the perihelion of Mercury's progression, and gave the correct equations for the gravitational field. At this point, the basic problems of general relativity were solved, and the theory of general relativity was born.In 1916, Einstein completed a long paper, "Foundations of General Relativity", in which he first called the theory of relativity, which had previously been applied to the inertial system, the special theory of relativity, and the principle that the laws of physics hold equally well only for the inertial system, the principle of special relativity, and further formulated the general relativity Principle: The laws of physics must hold for a frame of reference that is moving either way. Einstein's general theory of relativity states that space and time are curved due to the presence of matter, and that the gravitational field is actually a curved spacetime. Einstein used the theory that the Sun's gravity bends space to explain well the 43 seconds in Mercury's perihelion progression that has been unexplained. The second major prediction of general relativity is the gravitational redshift, the shift of the spectrum toward the red end in a strong gravitational field, which was confirmed by astronomers in their astronomical observations in the 1920s. The third major prediction of general relativity is that gravitational fields deflect light,. The gravitational field closest to the Earth is the solar gravitational field, and Einstein predicted that distant starlight would be deflected by one point seven seconds if it passed over the surface of the Sun. 1919, at the instigation of the British astronomer Eddington, two expeditions were sent to two places to observe the total eclipse of the Sun, and the final conclusion reached after careful study was that the starlight did indeed undergo a one-point-seven-second deflection in the vicinity of the Sun. The Royal Society and the Royal Astronomical Society formally read out the observation reports, confirming that the conclusion of general relativity was correct. At the meeting, Thomson, the famous physicist and president of the Royal Society, said, "This is the most significant result on the theory of gravity achieved since the time of Newton," and "Einstein's theory of relativity is one of the greatest achievements of human thought." Einstein became a newsmaker when he wrote a popular introduction to relativity, A Short Introduction to Special and General Relativity, in 1916, which was reprinted 40 times by 1922, and translated into more than a dozen languages and widely circulated. The significance of relativity: A long time has passed since the establishment of special and general relativity, which has stood the test of practice and history and is universally recognized as a truth. The theory of relativity has had a tremendous impact on the development of modern physics and the development of modern human thought. The theory of relativity unifies classical physics in terms of logical thought and makes classical physics a perfect scientific system. Special relativity unified the two systems of Newtonian mechanics and Maxwell electrodynamics on the basis of the principle of special relativity, pointing out that they all obey the principle of special relativity and are all covariant to the Lorentz transformations, and that Newtonian mechanics is nothing more than a good approximation of the laws of an object in a low-speed motion. General relativity theory again on the basis of generalized covariance, through the principle of equivalence, established the relationship between the local inertial length and the universal reference coefficients, obtained the generalized covariance form of all the physical laws, and established the generalized covariance theory of gravity, and Newtonian gravitational theory is only a first-class approximation of it. This fundamentally solved the previous problem of physics being limited to inertial coefficients and logically rationalized it. The theory of relativity rigorously examines time, space, matter and motion, which are the basic concepts of physics, and gives a scientific and systematic view of space-time and matter, thus making physics logically a perfect scientific system. The special theory of relativity gives the laws of motion of objects at high speeds and suggests that mass is equivalent to energy, giving the mass-energy relation equation. These two results are not obvious for macroscopic objects moving at low speeds, but they show extreme importance in the study of microscopic particles. Because microscopic particles generally move fast, some approaching or even reaching the speed of light, the physics of particles cannot be separated from the theory of relativity. The mass-energy relativistic equation not only created the necessary conditions for the establishment and development of quantum theory, but also provided the basis for the development and application of atomic nuclear physics. Most of the physicists on earth at that time, including Lorentz, the founder of the relativistic transformation relation, found it difficult to accept these brand-new concepts introduced by Einstein. It was even said that "only two and a half people in the world understood the theory of relativity at that time". The obstacles of the old way of thinking made this new physical theory unfamiliar to the majority of physicists until a generation later, and even the Royal Swedish Academy of Sciences, when awarding the Nobel Prize for Physics to Albert Einstein in 1922, only said, "For his contributions to theoretical physics, and even more so for his discovery of the law of the photoelectric effect." Einstein's Nobel Prize in Physics was awarded with no mention of Einstein's theory of relativity.

E = mc^2

The law of indestructibility of matter, which states that the mass of matter is indestructible; and the law of conservation of energy, which states that the energy of matter is conserved. (Law of Conservation of Information) Although these two great laws were discovered one after another, they were thought to be two unrelated laws, each describing a different law of nature. Some people even thought that the law of indestructibility of matter was a chemical law and the law of conservation of energy was a physical law, and that they belonged to different scientific categories. According to Albert Einstein, the mass of matter is a measure of inertia, and energy is a measure of motion; energy and mass are not isolated from each other, but are interconnected and inseparable. A change in the mass of an object will cause a corresponding change in the energy; and a change in the energy of an object will cause a corresponding change in the mass. In the special theory of relativity, Einstein put forward the famous mass-energy formula: E = mc^2 (here E represents the energy of an object, m represents the mass of an object, and c represents the speed of light, i.e., 3×10^8m/s). Einstein's theory was initially opposed by many people, and even some famous physicists at that time were skeptical of the young man's paper. However, with the development of science, a large number of scientific experiments proved that Einstein's theory was correct, and Einstein jumped to become a world-famous scientist and the world's greatest scientist in the 20th century. Einstein's mass-energy relationship formula, correctly explains a variety of atomic nuclear reactions: take helium 4, its atomic nucleus is composed of 2 protons and 2 neutrons. As a rule, the mass of the nucleus of Helium 4 is equal to the sum of the masses of the 2 protons and 2 neutrons. In reality, such arithmetic does not hold true; the mass of the helium nucleus is 0.0302 atomic mass units less than the sum of the masses of the 2 protons and 2 neutrons [57]! Why is this? Because when 2 deuteron[dao] nuclei (each containing 1 proton, 1 neutron) polymerize to form 1 helium 4 nucleus, a large amount of atomic energy is released. About 2.7 x 10^12 joules of atomic energy are released when 1 gram of helium 4 atoms is produced. Because of this, the mass of the helium-4 nucleus is reduced. This example vividly illustrates that when two deuterium nuclei are polymerized to form one helium-4 nucleus, it appears that mass is not conserved, i.e., the mass of the helium-4 nucleus is not equal to the sum of the masses of the two deuterium nuclei. However, using the mass-energy relationship formula, the mass lost by the helium-4 nucleus happens to be equal to the mass lost due to the release of atomic energy during the reaction! In this way, Einstein elucidated the essence of the law of indestructibility of matter and the law of conservation of energy from a newer height, pointed out the close relationship between the two laws, and made mankind's understanding of nature one step deeper.

The photoelectric effect

Light irradiated on certain substances causes changes in the electrical properties of the substances. This kind of photoelectric phenomenon is collectively known as the photoelectric effect (Photoelectric effect). Photoelectric effect is divided into photoelectron emission, photoconductive effect and photovoltaic effect. The first phenomenon occurs on the surface of the object, also known as the external photoelectric effect. The latter two phenomena occur inside the object, known as the internal photoelectric effect. Hertz discovered the photoelectric effect in 1887, and Einstein was the first to successfully explain the photoelectric effect. Metal surfaces under the action of light irradiation emission of electrons effect, the emission of electrons called photoelectrons. The wavelength of light is less than a certain critical value can emit electrons, that is, the limiting wavelength, corresponding to the frequency of light is called the limiting frequency. The critical value depends on the metal material, and the energy of the emitted electrons depends on the wavelength of the light and has nothing to do with the intensity of the light, which cannot be explained by the volatility of light. There is also a contradiction with the volatility of light, that is, the photoelectric effect of transient, according to the theory of volatility, if the incident light is weak, the irradiation time to be a little longer, the electrons in the metal in order to accumulate enough energy to fly out of the metal surface. But the fact is that, as long as the frequency of light is higher than the limiting frequency of the metal, the brightness of the light, regardless of the strength, the production of photons is almost instantaneous, no more than ten minus nine times the square second. The correct interpretation is that light must consist of strictly defined units of energy (i.e., photons or light quanta) related to wavelength. In the photoelectric effect, the direction of electron emission is not completely directional, but most of them are perpendicular to the metal surface emission, and the direction of light has nothing to do with the light, light is an electromagnetic wave, but the light is a high-frequency oscillation of orthogonal electromagnetic field, the amplitude is very small, and will not have an impact on the direction of the electron emission. In 1905, Einstein proposed the photon hypothesis, successfully explained the photoelectric effect, and therefore won the 1921 Nobel Prize in Physics.

"God does not roll the dice"

Einstein used to be one of the catalysts of quantum mechanics, but he was not satisfied with the subsequent development of quantum mechanics, Einstein always believed that "quantum mechanics (Copenhagen Interpretation headed by Born: "Basically, quantum systems are described in terms of chance. The chance of an event is the absolute value of the wave function squared.") Incomplete", but suffered from the lack of a good model of interpretation, there is the famous "God does not roll the dice" of the negative cry! In fact, Einstein's intuition is right, the quantum interpretation of determinism is the "quantum interpretation" of the real, the root. Einstein did not accept quantum mechanics as a complete theory until his death. Einstein also famously said, "Does the moon only exist when you look at it?"

The cosmological constant

In proposing the theory of relativity, Einstein had included the cosmological constant (to explain the existence of a static universe with a non-zero density of matter, he introduced a term proportional to the gauge tensor in the gravitational field equations, which he denoted by the symbol ∧. This constant of proportionality is so small that it is negligible on the galactic scale. It is only at the cosmic scale that ∧ can be meaningful, so it is called the cosmological constant. (i.e., the fixed value of the so-called antigravity) is substituted into his equation. He argued that there is an antigravity force that balances gravity and drives the universe to be finite and static. When Hubble proudly showed it to Einstein at the telescope, Einstein was mortified and said, "This is the biggest mistake I have ever made in my life." The universe is expanding! Hubble and others argued that antigravity does not exist, and that the expansion is being driven slower and slower due to the gravitational pull between galaxies. So, was Einstein completely wrong? No. There is a torsional force between galaxies that drives the expansion of the Universe, dark energy, and seven billion years ago, they "beat" dark matter and became the dominant force in the Universe. The latest research shows that dark matter and dark energy make up about 96% of the universe in terms of mass content (only real mass, not imaginary matter). It seems that the universe will continue to expand at an accelerating rate until it disintegrates and dies. (There are other theories as well, which are currently debated). Although the cosmological constant exists, the value of antigravity far exceeds gravity. It is no wonder that this stubborn physicist argued with Bohr in quantum mechanics, "God doesn't roll the dice!" (Don't command how God determines the fate of the universe.) Linde raps, "Now, I finally understand why he [Einstein] liked the theory so much that he still studies the cosmological constant all these years later, and the cosmological constant remains one of the biggest questions in physics today."