Urgent request: Briefly describe Einstein's contribution to the development of physics and its significance.

Details of Einstein's contribution to astronomy:

An epoch-making scientist, the founder and founder of modern physics. His work had a huge impact on astronomy and astrophysics.

Born on March 14, 1879 in the town of Ulm, Germany, he spent his youth in Switzerland. Graduated from the Technical University of Zurich in 1900. I became unemployed after graduation. After two years of hard work, he found a permanent job at the Patent Office in Bern. A series of his early historic contributions were made here. In 1909, he began teaching at the university. In 1914, he was invited to return to Germany and served as director of the Wilhelm Royal Institute of Physics and professor at the University of Berlin. When Hitler came to power in 1933, Einstein was persecuted for the first time because he was a Jew and he resolutely defended democracy. He was forced to move to Princeton in the United States. He became a U.S. citizen in 1940. Died in Princeton on April 18, 1955.

The late nineteenth century was a period of change in physics, with new experimental results impacting the classical physics system established since Galileo and Newton. The older generation of theoretical physicists represented by Lorenz and others tried to resolve the contradiction between old theories and new facts within the original theoretical framework. Einstein re-examined the most basic concepts of physics based on experimental facts, abandoned some familiar but incorrect concepts, and made fundamental breakthroughs in theory. Some of his major achievements greatly promoted the development of astronomy.

One of Einstein's seminal contributions was the development of quantum theory. Quantum theory is a hypothesis proposed by Planck in 1900 to solve the black body radiation spectrum. He believed that the energy emitted when an object emits radiation is not continuous, but quantized. However, most people, including Planck himself, did not dare to push the concept of energy discontinuity one step further, and even repeatedly tried to incorporate this concept into the system of classical physics. Eichstein's attitude was completely different. He had a premonition that quantum theory would bring not small corrections, but fundamental changes to the entire physics. He pushed quantum theory forward, used quantum concepts to analyze the propagation and absorption of radiation, proposed the concept of light quantum, and perfectly explained the empirical laws of the photoelectric effect that could not be explained by classical physics, thus shaking the orthodox status of the wave theory of light. The proposal of the concept of light quantum revealed for the first time in the history of human understanding of nature that light has both wave and particle properties (now commonly known as duality). It directly contributed to the establishment of de Broglie's material wave theory and the subsequent quantum mechanics. The establishment opened the way. This work won the 1921 Nobel Prize in Physics. In 1906, Einstein extended quantum theory to vibrations inside objects, and successfully explained the relationship between the specific heat of solids and temperature changes at low temperatures. In 1916, he continued to develop quantum theory and derived blackbody radiation from Bohr's concept of quantum transition. In this research, he combined the concepts of statistical physics with quantum theory and proposed the concepts of spontaneous emission and stimulated emission. From the foundation of quantum theory to the concept of stimulated emission, it has a great impact on astrophysics, especially theoretical astrophysics. The first mature aspect of theoretical astrophysics, the theory of stellar atmospheres, was established on the basis of quantum theory and radiation theory.

The hallmark of Einstein's lifelong work is his theory of relativity. In a paper entitled "On the Electrodynamics of Moving Bodies" published in 1905, he fully proposed the special theory of relativity. He transformed the basic concepts of time, space and motion in classical physics based on two universal generalizations: the relativity of the inertial reference system and the invariance of the speed of light. It denies the existence of absolutely static space and denies the absoluteness of the concept of simultaneousness. In this system, the moving ruler shortens and the moving clock slows down. One of the most remarkable results of special relativity is the connection between energy and mass. The famous relationship E=mc^2 has become the golden key to unlock the theory of nuclear energy. The discovery of nuclear energy finally satisfactorily solved the long-standing problem of stellar energy. In recent years, more and more high-energy astrophysical phenomena have been discovered, and special relativity has become one of the most basic theoretical tools to explain such phenomena.

After the establishment of the special theory of relativity, Einstein began to devote himself to the research of the theory of gravity. Just like in the work of establishing the special theory of relativity, he also grasped a well-known basic fact, that is: the ratio of inertial mass to gravitational mass is a universal constant that has nothing to do with physical properties. Based on this, he proposed the principle of equivalence.

After years of hard work, a gravity theory that was essentially completely different from Newton's gravity theory—general relativity—was finally established in 1915. General relativity has been closely related to astronomical phenomena from the beginning. A series of key tests of general relativity are all completed in the "laboratory" of the universe. According to the general theory of relativity, Einstein deduced the (abnormal) precession of Mercury's perihelion, solving a mystery that has remained unsolved for many years in astronomy. At the same time, he reasoned that light bends in a gravitational field. This prediction was confirmed in 1919 by Eddington and others through the observation of a solar eclipse. Sixty-two years later, in 1978, the periodic variation of the radio pulsar binary PSR1913+16 was measured. Many people believed that it fully conformed to the predictions made by the gravitational wave damping theory, and may be another powerful proof of the general theory of relativity. In the case of strong gravitational fields, general relativity has many unique conclusions. For example, Oppenheimer predicted based on the general theory of relativity that after a star uses up its nuclear energy, if it is massive enough, it will inevitably evolve into a black hole. After the pulsar was discovered in 1967 and confirmed to be a neutron star, people realized that there were indeed strong field objects in the sky. Now, Cygnus X-1 is thought to be a black hole. All the above constitute the basic content of relativistic astrophysics, which is currently one of the most active branches of astrophysics.

Nothing best represents Einstein’s significant impact on astronomy than his cosmological theory. After Einstein established the general theory of relativity, he immediately turned to the investigation of the universe. In 1917, Einstein published his first cosmological paper, "Investigations of Cosmology in the Light of the General Theory of Relativity." Like the many times he created a field with one paper, this paper announced the birth of the theory of relativity. Although more than sixty years have passed, many of the concepts introduced in this paper are still vital today. In exploring the universe, Einstein first pointed out the insurmountable inherent contradiction between the infinite universe and Newton's theory. In principle, the dynamics of the physical system of the infinite universe cannot be established based on Newtonian mechanics. Starting from the two points of Newton's theory and the infinite universe, we cannot get a self-consistent universe model at all. Therefore, it is necessary to either modify Newton's theory, modify the concept of infinite space, or modify both. Einstein abandoned the traditional infinity of the three-dimensional Euclidean geometry of the universe. He established a static finite and boundless self-consistent dynamic universe model based on the general theory of relativity. In this model, the universe is a closed continuum in terms of its spatial extension. The volume of this continuous area is finite, but it is a curved closed body and therefore has no boundaries.

Einstein introduced the method of using dynamics to establish a universe model in the study of cosmology, and introduced new concepts such as cosmological principles and curved space. Moreover, he argued that the question of whether the volume of the universe is infinite or finite can only be solved by relying on science rather than relying on faith. This attitude of advocating science inherits the spirit of scientific exploration pioneered by Copernicus and others. He once said: "Scientific research can break superstition because it encourages people to think and observe things based on causal relationships." His cosmological research embodies this spirit of opposing superstition. Therefore, whether those who agree with or oppose his concept of the universe, they have to admit that Einstein also wrote a very glorious page in cosmology.

Albert Einstein, the greatest physicist of the 20th century, was born on March 14, 1879, in the city of Ulm in southwest Germany. He moved to Munich with his family a year later. Einstein's parents were both Jewish. His father, Hermann Einstein, and his uncle, Jacob Einstein, jointly opened an electrical appliance factory that produced motors, arc lamps, and electrical instrumentation for power stations and lighting systems. Mother Pauline was a housewife with a secondary education. She loved music very much and taught Einstein to play the violin when he was six years old.

Einstein was not lively when he was a child. He could not speak even when he was more than three years old. His parents were worried that he was mute and took him to a doctor for examination. Fortunately, little Einstein was not mute, but he could not speak very smoothly until he was nine years old. Every word he spoke had to be thought through laboriously but carefully.

When Einstein was four or five years old, he was bedridden and his father gave him a compass. When he found that the compass always pointed in a fixed direction, he was very surprised and felt that there must be something deeply hidden behind this phenomenon.

He happily played with the compass for several days and pestered his father and Uncle Jacob with a series of questions. Although he couldn't even pronounce the word "magnetism" well, he stubbornly wanted to know why the compass could guide. This profound and lasting impression could still be vividly recalled by Einstein until he was sixty-seven years old.

When Einstein was in elementary school and middle school, his homework was ordinary. Because he behaves slowly and doesn't like to interact with others, his teachers and classmates don't like him. The teacher who taught him Greek and Latin was even more disgusted with him. He once publicly scolded him: "Einstein, you will definitely not be successful when you grow up." And because he was afraid that he would affect other students in class, he actually wanted to Kick him out of school.

Einstein's uncle Jacob was responsible for technical matters in the electrical appliance factory, while Einstein's father was responsible for business dealings. Jacob was an engineer and loved mathematics very much. When little Einstein came to him to ask questions, he always introduced mathematical knowledge to him in very simple and popular language. Under the influence of his uncle, Einstein received early enlightenment in science and philosophy.

My father’s business is not doing well, but he is an optimistic and kind-hearted person. The family invites poor students who come to Munich to study one night a week for dinner, which is equivalent to providing relief to them. Among them are a pair of Jewish brothers Max and Bernard from Lithuania. They are both studying medicine and like to read books and have a wide range of interests. They were invited to Einstein's house for dinner and made good friends with the shy little Einstein, who had black hair and brown eyes.

Max can be said to be Einstein’s “initial teacher”. He borrowed some popular natural science books for him to read. Max gave Einstein a copy of Spilke's plane geometry textbook when he was twelve years old. When Einstein recalled this sacred little book in his later years, he said: "There are many assertions in this book, for example, that the three altitudes of a triangle intersect at one point. Although they are not obvious in themselves, they can be proved very reliably. So that any doubt seemed impossible. This clarity and reliability made an indescribable impression on me."

Einstein was also fortunate to know from an excellent popular book. The popular science books not only enhanced Einstein's knowledge, but also touched the curious heartstrings of young people and caused him to think deeply about the problem.

When Einstein was sixteen years old, he entered the Engineering Department of the Federal University of Technology in Zurich, Switzerland, but failed the entrance examination. He accepted the advice of Professor Weber, the president of the Federal University of Technology and the school's famous physicist, and completed high school courses at the state high school in Aarau, Switzerland, to obtain a high school diploma.

In October 1896, Einstein entered the Technical University of Zurich and studied mathematics and physics in the Normal Department. He is very disgusted with the injective education in schools, believing that it leaves people with no time or interest to think about other issues. Fortunately, the compulsory education that stifles true scientific drive is much less common at Zurich's Federal University of Technology than at other universities. Einstein made full use of the free atmosphere in school and focused his energy on the subjects he loved. In school, he read extensively the works of physics masters such as Helmholtz and Hertz. He was most fascinated by Maxwell's electromagnetic theory. He has the ability to self-study, the habit of analyzing problems and the ability to think independently.

Early work

In 1900, Einstein graduated from the Technical University of Zurich. Due to his lack of enthusiasm for certain subjects and his indifference to teachers, he was refused a stay in school. Unable to find a job, he made a living as a tutor and substitute teacher. After being unemployed for a year and a half, Marcel Grossman, a classmate who cared about and understood his talents, reached out to him for help. Grossmann managed to persuade his father to introduce Einstein to the Swiss Patent Office as a technician.

Einstein was forever grateful to Grossman for his help. In a letter to commemorate Grossman, he talked about this incident and said that when he graduated from college, he was "suddenly abandoned by everyone and helpless to face life. He helped me, and through him and his father, I Later, I went to Halle (the director of the Swiss Patent Office at the time) and entered the patent office. This was a bit like a life-saving grace. Without him, I probably wouldn’t have starved to death, but my spirit would have become depressed.”

On February 21, 1902, Einstein obtained Swiss citizenship and moved to Bern, waiting for recruitment by the Patent Office.

On June 23, 1902, Einstein was officially employed by the Patent Office as a third-level technician. His job responsibilities were to review various technological inventions and creations applying for patent rights. In 1903, he married his college classmate Mileva Marik.

From 1900 to 1904, Einstein wrote a paper every year and published it in the German Journal of Physics. The first two articles were about the thermodynamics of liquid surfaces and electrolysis, in an attempt to provide a mechanical basis for chemistry. Later, I found that this path was unavailable, and I turned to the study of the mechanical basis of thermodynamics. In 1901, some basic theories of statistical mechanics were proposed, and three papers from 1902 to 1904 all belonged to this field.

The 1904 paper carefully explored the fluctuations predicted by statistical mechanics and found that energy fluctuations depended on Boltzmann's constant. It not only applied this result to mechanical systems and thermal phenomena, but also boldly applied it to radiation phenomena to derive the formula for the fluctuation of radiant energy, thereby deriving Wien's displacement law. The study of fluctuation phenomena enabled him to make major breakthroughs in both radiation theory and molecular kinetic theory in 1905.

The Miracle of 1905

In 1905, Einstein created an unprecedented miracle in the history of science. He wrote six papers this year. In the six months from March to September, he used his spare time after working eight hours a day at the Patent Office to make four epoch-making contributions in three fields. He published Four important papers were published on the quantum theory of light, molecular size determination, Brownian motion theory and special relativity.

In March 1905, Einstein sent the paper he believed to be correct to the editorial office of the German "Annals of Physics". He shyly said to the editor: "I would be very happy if you could find space in your annual report to publish this paper for me." The paper he was "embarrassed" to send was called "About Light" A Speculative View of Generation and Transformation”.

This paper extends the quantum concept proposed by Planck in 1900 to the propagation of light in space and proposes the light quantum hypothesis. It is believed that: for time averages, light behaves as fluctuations; for instantaneous values, light behaves as particles. This is the first time in history that the unity of wave nature and particle nature of microscopic objects is revealed, that is, wave-particle duality.

At the end of this article, he used the concept of light quantum to easily explain the photoelectric effect that cannot be explained by classical physics, and deduced the relationship between the maximum energy of photoelectrons and the frequency of incident light. This relationship was experimentally confirmed by Millikan 10 years later. In 1921, Einstein won the Nobel Prize in Physics for his "discovery of the law of the photoelectric effect."

This was just the beginning. Albert Einstein was advancing hand in hand in the three fields of light, heat, and electrical physics and was out of control. In April 1905, Einstein completed "A New Method for Determining the Size of Molecules" and in May he completed "The Movement of Suspended Particles in Hydrostatic Liquids Required by the Molecular Kinetic Theory of Heat". These are two papers on the study of Brownian motion. Einstein's purpose at that time was to determine the actual size of molecules by observing the irregular motion of suspended particles produced by the fluctuation phenomenon of molecular motion, so as to solve the atomic problem that has been debated in the scientific and philosophical circles for more than half a century. Does the problem exist?

Three years later, French physicist Perrin confirmed Einstein's theoretical predictions with sophisticated experiments. This irreproachably proved the objective existence of atoms and molecules. This led Ostwald, the German chemist who most firmly opposed atomic theory and the founder of energeticism, to proactively declare in 1908: "The atomic hypothesis has become a fundamental and solid foundation." scientific theory".

In June 1905, Einstein completed a long paper "On the Electrodynamics of Moving Bodies" that ushered in a new era of physics, and fully proposed the special theory of relativity. This is the result of Einstein's 10 years of brewing and exploration. It has largely solved the crisis of classical physics that emerged at the end of the 19th century, changed the concept of space and time in Newtonian mechanics, revealed the equivalence of matter and energy, and created the A brand new world of physics is the greatest revolution in the field of modern physics.

Special relativity can not only explain all phenomena that classical physics can explain, but also explain some physical phenomena that classical physics cannot explain, and predicts many new effects. The most important conclusion of the special theory of relativity is that the principle of conservation of mass has lost its independence. It is integrated with the law of conservation of energy. Mass and energy can be converted into each other.

Others include the more commonly mentioned clocks slowing down, the speed of light remaining unchanged, the rest mass of photons being zero, etc. Classical mechanics has become a limiting case of relativistic mechanics when moving at low speeds. In this way, mechanics and electromagnetism are unified on the basis of kinematics.

In September 1905, Einstein wrote a short article "Is the inertia of an object related to the energy it contains?" ", as a corollary of the theory of relativity. Mass-energy equivalence is the theoretical basis of nuclear physics and particle physics, and also opened the way for the release and utilization of nuclear energy realized in the 1940s.

In this short period of six months, Einstein's breakthrough achievements in science can be said to be "ground-breaking and unprecedented." Even if he gave up the study of physics, even if he only completed any of the above three aspects of achievements, Einstein would have left an extremely important mark in the history of the development of physics. Einstein cleared away the "dark clouds in the clear sky of physics" and ushered in a more glorious new era of physics.

Exploration of the general theory of relativity

After the establishment of the special theory of relativity, Einstein was not satisfied and tried to extend the scope of application of the principle of relativity to non-inertial systems. He found a breakthrough from the ancient experimental fact that all objects in the gravitational field have the same acceleration discovered by Galileo, and proposed the equivalence principle in 1907. In this year, his university teacher and famous geometer Minkovsky proposed a four-dimensional space representation of the special theory of relativity, which provided a useful mathematical tool for the further development of the theory of relativity. Unfortunately, Einstein did not realize its value at the time. .

Einstein considered the discovery of the equivalence principle to be the happiest thought in his life, but his subsequent work was very difficult and took a lot of detours. In 1911, he analyzed a rigid rotating disk and realized that Euclidean geometry was not strictly valid in gravitational fields. At the same time, it was also discovered that the Lorenz change is not universal, and the equivalence principle is only valid for infinitely small areas... At this time, Einstein already had the idea of ??general relativity, but he still lacked the mathematical foundation necessary to establish it.

In 1912, Einstein returned to work at his alma mater in Zurich. With the help of Grossmann, his classmate and professor of mathematics at his alma mater, he found the mathematical tools to establish the general theory of relativity in Riemannian geometry and tensor analysis. After a year of hard cooperation, they published the important paper "Outline of General Relativity and Theory of Gravity" in 1913, proposing the metric field theory of gravity. This is the first time that gravity and metrics have been combined to give Riemannian geometry real physical meaning.

However, the gravitational field equation they obtained at that time was only covariant for linear transformations, and did not yet have covariance under any coordinate transformation required by the principle of general relativity. This is because Einstein was not familiar with tensor operations at the time and mistakenly believed that as long as he adhered to the law of conservation, he had to limit the choice of coordinate systems. In order to maintain causality, he had to give up the requirement of universal covariance.

The second peak of scientific achievements

The three years from 1915 to 1917 were the second peak of Einstein’s scientific achievements. Similar to 1905, he It has also achieved historic achievements in three different fields. In addition to the final completion of the general theory of relativity in 1915, which is recognized as one of the greatest achievements in the history of human thought, the theory of gravitational waves in terms of radiation quantum was proposed in 1916, and modern cosmology was created in 1917.

After July 1915, after more than two years of detours, Einstein returned to the requirement of universal covariance. From October to November 1915, he concentrated on exploring new gravitational field equations and submitted four papers to the Prussian Academy of Sciences on November 4, 11, 18 and 25.

In the first paper, he obtained the universal covariant gravitational field equation that satisfies the conservation law, but added an unnecessary restriction. In the third paper, based on the new gravitational field equation, it was calculated that the deflection of light passing through the surface of the sun is 1.7 arc seconds. It was also calculated that the precession of Mercury's perihelion every 100 years was 43 seconds, which completely solved the problem that has been solved for more than 60 years. One of the great problems of astronomy.

In his paper "Field Equations of Gravity" on November 25, 1915, he gave up unnecessary restrictions on the transformation group, established a truly universal covariant gravitational field equation, and declared the general theory of relativity as a This logical structure is finally completed.

In the spring of 1916, Einstein wrote a concluding paper "The Foundations of General Relativity"; at the end of the same year, he wrote a popular pamphlet "A Brief Introduction to Special and General Relativity".

In June 1916, while studying the approximate integral of the gravitational field equation, Einstein discovered that when a mechanical system changes, it will inevitably emit gravitational waves propagating at the speed of light, thus proposing the gravitational wave theory. In 1979, 24 years after Einstein's death, the existence of gravitational waves was indirectly proven.

In 1917, Einstein used the results of general relativity to study the space-time structure of the universe and published his groundbreaking paper "An Investigation of the Universe According to the General Theory of Relativity." The paper analyzes the traditional concept that "the universe is infinite in space" and points out that it is incompatible with Newton's gravity theory and general relativity. He believes that the possible way out is to regard the universe as a self-closed continuous area with a limited space volume, and use scientific arguments to deduce that the universe is finite and boundless in space. This is a bold initiative in human history, making the universe Science got rid of the speculation of pure conjecture and entered the field of modern science.

A long and difficult exploration

After the completion of the general theory of relativity, Einstein still felt dissatisfied and wanted to extend the general theory of relativity to include not only the gravitational field, but also the electromagnetic field. He believed that this was the third stage in the development of relativity, that is, unified field theory.

After 1925, Einstein went all out to explore a unified field theory. In the first few years, he was very optimistic and thought that victory was in sight; later he found many difficulties and he believed that the existing mathematical tools were not enough; after 1928, he turned to the exploration of pure mathematics. He tried various methods, but failed to achieve results of real physical significance.

In the 30 years from 1925 to 1955, apart from the completeness of quantum mechanics, gravitational waves and the motion problems of general relativity, Einstein devoted almost all of his scientific and creative energy to The search for unified field theory.

In 1937, with the cooperation of two assistants, he derived the equations of motion from the gravitational field equations of general relativity, further revealing the unity between space, time, matter, and motion. This is the generalized theory of The major development of the theory of relativity was also the last major achievement achieved by Einstein in his scientific creation activities.

In terms of the same theory, he never succeeded. He never got discouraged and started from the beginning with full confidence every time. Because he stayed away from the mainstream of physics research at that time and attacked problems on his own that were unsolvable at the time, he was very isolated in the physics community in his later years, contrary to his situation in the 1920s. However, he remained fearless and unswervingly followed the path he had identified. Until the day before his death, he was still preparing to continue his mathematical calculations on the unified field theory in his hospital bed.