Thus, A. Michelson's experiment proves that contrary to our conjecture, the propagation of light and the principle of relativity of motion are not contradictory, but completely consistent.
Relativity principle of combined motion. In other words, the reasoning we made in the last section "Will the principle of relativity of motion be shaken?" Is completely wrong.
The research object of relativity is the high-speed moving world and the vast universe beyond our daily experience, which is the main reason why it is difficult for us to understand relativity.
Since the birth of the theory of relativity, the revolution of time and space brought by it has greatly expanded human understanding of the universe. From the theory of relativity, people have discovered the mystery of time travel, the great energy of atomic fission, the origin and end of the universe, black holes and dark energy and other wonderful phenomena. Almost all the mysteries of the universe are hidden in the simple formula of relativity.
Special relativity proves that high-speed travel will slow down time. Assuming that at some point in the future, people have solved all the technical problems and can build a spaceship flying at sub-light speed, time travel in a sense will become possible. If the spaceship flies from the earth to a distant galaxy at sub-light speed, it will take only a few years to go back and forth (according to the time on the spaceship), but during this time, thousands of years have passed on the earth and everything has changed dramatically. If human civilization still exists, what new look will it be?
General relativity shows that space-time can be curved, not flat. We can cut a wormhole between the earth and the distance of the universe, and then open this hole with some kind of "strange substance" to make it become a hyperspace pipeline that suddenly appears in the universe, allowing us to reach the other side of the distance in an instant. Then when we came back, the strange nature of the wormhole made us much younger.
General relativity determines that enough mass can change and distort space-time, mathematician Frank? Based on this, Dipler conceived a time travel method of rolling up time and space. He believes that if there is a huge object in space rotating at half the speed of light, space-time will be twisted and folded back. So in the future, as long as someone makes a huge cylinder, its length is about 10 times the diameter, and then makes the cylinder rotate at the speed of 150000 km/s, it will create a twisted and folded space-time near the center of the cylinder.
In order to use this cylinder as a time machine, the spacecraft must travel to the center of the cylinder and fly along the inner wall of the cylinder: sailing against the rotation direction of the cylinder means driving into the past, and sailing along the rotation direction of the cylinder means driving into the future, so that the spacecraft will go deeper into the past or future every time it turns. When the time traveler arrives at the destination time, he drives the spaceship away from the cylinder. It must be understood that, like all theoretical time machines, it is impossible to reach an earlier time than making a cylinder through past voyages.
Time travel is a wonderful and fascinating topic. For a long time, scientists have put forward one scheme after another, and the possible problems of time travel have also been heatedly discussed. One day, the fascinating light of relativity will shine on us and start real-time travel.
Atomic fission
1905 1 1 In June, Einstein also published a second article on special relativity in the German journal of physics: "Is the inertia of an object related to the energy it contains? This is a short article, in which he points out that the mass of an object is not constant, but increases with the speed of motion. This is the "mass increase effect" of moving objects.
Now let's imagine that we are pushing a small scooter, which is very light and has nothing on it. Suppose this is an "ideal" scooter in a vacuum, without any friction or resistance. So as long as we keep pushing, its speed will get faster and faster, but as time goes by, its quality will get bigger and bigger. At first, it looks like a car full of steel, then it seems to be full of a Himalayan mountain, and then it seems to be full of an earth, a solar system and a galaxy ... At this time, no matter how hard you push, no matter how long you push, it can't go any faster.
Therefore, because a photon travels at the speed of light, its rest mass must be equal to zero, otherwise its moving mass will be infinite.
When an object moves close to the speed of light, we constantly apply external force to the object to supply energy, but the speed of the object becomes more and more difficult to increase. Where is the energy we use? In fact, energy has not disappeared, but has been transformed into mass. In other words, the increase of mass of an object is closely related to the increase of kinetic energy, or the mass of an object is closely related to energy. In the process of explaining this relationship, Einstein put forward a famous mass-energy relationship: E=mc2.
Energy equals mass times the square of the speed of light, which is thrilling even for pure theoretical physicists who don't care much about practical value. In most people's eyes, energy is equal to the square of mass times the speed of light, that is, energy is 9 trillion times that of mass. What an attractive prospect! If the mass of a substance the size of a fingernail disappears completely, the energy released will be calculated as 10,000 tons of coal.
Unfortunately, no one can casually reduce the quality, such as a stone. We can break it into small pieces with a hammer and grind it into pieces, but when you collect these pieces carefully, you will find that its quality has not changed.
However, ten years later, 1939, Iori Yagami? Madame Curie, Fermi and szilard independently discovered the chain reaction, which enabled mankind to find a way to release huge atomic energy. When the nucleus of uranium -235 is bombarded by neutrons, it will split into two new nuclei with medium mass, releasing 1 ~ 3 neutrons and releasing huge energy. These neutrons can cause other uranium nuclei to split again, and so on, forming a chain reaction and releasing huge energy. This is the chain reaction.
BIGBANG
To our contemporary surprise, until 19 17, the smartest human brain still thought that our galaxy was the whole universe, and the universe the size of this galaxy would always be stable, neither bigger nor smaller. This is the steady-state cosmology that has been circulating for thousands of years.
19 17, Einstein tried to deduce the model of the whole universe according to the equation of general relativity, but he found that in such a model with only gravity, the universe either expanded or contracted. In order to keep the model of the universe still, Einstein added a new concept to his equation-cosmological constant, which represents a repulsive force, contrary to gravity, and increases with the distance between celestial bodies. This is an imaginary force that counteracts the action of gravity.
However, Einstein soon found himself wrong. Because scientists soon discovered that the universe is actually expanding!
Hubble, the father of astronomy in the 20th century, first observed this. Hubble 1889 was born in Missouri, USA, and graduated from the Astronomy Department of the University of Chicago. 1929, Hubble discovered that all the galaxies are moving away from us, which shows that the universe is expanding. This expansion is a uniform expansion of the whole space, so any observer will see exactly the same expansion. From the perspective of any galaxy, all galaxies revolve around it, and the farther away the galaxy is, the faster it unfolds.
The expansion of the universe means that in the early days, the distance between stars was closer, and at some point in the more distant past, they seemed to be in the same small range.
When the news of the expansion of the universe reached the famous physicist Gamov, it immediately aroused the interest of the scholar. George? Gamov was born in Russia. He was deeply interested in poetry, geometry and physics since he was a child, and became a favorite pupil of physicist Friedman in college. Friedman put forward an important model of cosmic expansion after Einstein, and Gamov became one of the enthusiastic supporters of the theory of cosmic expansion. 1945, the first atomic bomb exploded successfully in human history. Looking at the photo of mushroom cloud rising, Gamov suddenly got inspiration: "Enlarge the atomic bomb to infinity". Isn't that BIGBANG? He combined the knowledge of nuclear physics with the theory of cosmic expansion, and gradually formed his own theoretical system of the Big Bang universe.
1948, Gamov and his student Alpha wrote a famous paper, which systematically put forward the theory of the origin and evolution of the universe. Different from our usual thinking, the big bang that created the universe was not the kind of explosion that happened at a certain point and then spread into the surrounding air, but the space itself was expanding, and the galactic matter separated with the expansion of the space.
According to the Big Bang cosmology, the very early universe was a huge homogeneous gas composed of microscopic particles, with extremely high temperature, extremely high density and extremely high expansion speed. Gamov also made an unusual prediction: our universe is still bathed in the residual radiation of the early high-temperature universe, but the temperature has dropped to about 6 K, just like a furnace, although there is no fire, it can still release a little heat.
1964, penzias and Wilson, young engineers of American Bell Telephone Company, stumbled upon the residual radiation of the early universe predicted by Gamow. After measurement and calculation, it is concluded that the temperature of this residual radiation is 2.7K (lower than that predicted by Gamow), which is generally called 3K cosmic microwave background radiation. This discovery strongly supports the Big Bang theory.
The wisdom of general relativity lies in that it can describe the whole universe from its birth, even those unknown fields. It is really overqualified to deal with such a small and ordinary space-time field as the solar system.
Cosmic constant comes from dark energy.
After discovering the fact that the universe is expanding, Einstein hastily deleted the cosmological constant term from his equation, thinking that the cosmological constant was "the biggest mistake in his life". Subsequently, the cosmological constant was thrown into the garbage dump of history.
However, nature played a trick on people, and decades later, the cosmological constant was resurrected like a ghost. The revival of the cosmological constant is attributed to the discovery of dark energy.
1998, astronomers found that the universe is not only expanding, but also expanding outward at an unprecedented acceleration, and all distant galaxies are moving away from us faster and faster. Then there must be some hidden force accelerating the tearing of galaxies in the dark. This is a repulsive energy, which scientists call "dark energy". In recent years, scientists have confirmed through various observations and calculations that dark energy not only exists, but also dominates the universe. Its total amount accounts for about 73% of the universe, while dark matter accounts for about 23%, and ordinary matter only accounts for about 4% in the universe. We always think that there are enough stars in the sky. What else in the universe can compare with them? Now, we find that the stars in the sky are "vulnerable groups", and most of the rest are we know little or nothing. How can this not make people feel thrilling?
In fact, as early as 1930, astrophysicists pointed out that Einstein's cosmological equation with cosmological constant could not lead to a completely static universe: because gravity and cosmological constant are unstable balance, a small disturbance may lead to uncontrolled expansion and contraction of the universe. The discovery of dark energy tells us that Einstein's cosmological constant, as a counterbalance to gravity, not only really exists, but also greatly disturbs our universe, making the expansion speed of the universe seriously out of control. After a series of twists and turns, the cosmological constant is resurrected in time.
Today, the cosmological constant appears in front of the world in the form of dark energy, and its surging repulsive force has discolored the whole universe! Since the birth of the universe, the struggle between dark energy and gravity has never stopped. In this long battle, the most important thing is the density of each other. The density of matter decreases with the space increase caused by the expansion of the universe; But when the universe expands, the density of dark energy changes very slowly, or remains unchanged at all. A long time ago, the density of matter was relatively high, so the universe at that time was in the stage of deceleration and expansion; At present, the density of dark energy is greater than that of matter, and repulsion has completely seized control from gravity, pushing the universe to expand at an unprecedented speed. According to some scientists' predictions, after more than 20 billion years, the universe will usher in a turbulent end, and the horrible dark energy will eventually tear all the galaxies, stars and planets one by one, leaving endless cold and darkness for the universe.
The discovery of dark energy also fully reflects that the cognitive process of human beings has entered a "paradox cycle": that is, the largest proportion in the universe is the last and most difficult for us to know. On the one hand, people now know more and more about the mysteries of the universe. On the other hand, we have to face more and more unknowns. This increasingly profound unknown, in turn, constantly stimulates mankind to explore the truth behind the universe.
How does dark energy come from? How will it develop? This has always been one of the most important problems faced by cosmology in 2 1 century.
Black hole discovery
General relativity shows that gravitational field can cause space bending, and strong gravitational field can cause strong space bending. What will happen to the infinitely strong gravitational field?
Shortly after Einstein 19 16 published the general theory of relativity, German physicist Karl? Schwarzschild used this theory to describe how the space and time around a hypothetical completely spherical star are curved. He proved that if the mass of a star is concentrated in a spherical area small enough, for example, when the mass of a celestial body is the same as that of the sun and the radius is only 3 kilometers, the intense squeezing of gravity will increase the density of that celestial body infinitely, and then it will collapse catastrophically, making the space-time there infinitely curved. In such a time and space, even light can't escape! Without the connection of optical signals, this space-time is divided into two areas with different properties from the outside space-time, and that divided sphere is the horizon.
This is the black hole we are familiar with today, but at that time, almost no one believed that there was such a strange celestial body, and even Einstein himself and Eddington, a master of relativity, clearly expressed their opposition to this monster. Einstein also said that he could prove that no star can reach infinite density. Even the name black hole was not named by American physicist Wheeler until 1967.
Of course, history will not stop because of this. In 1930s, American astronomer Chandraseka put forward the famous "Chandraseka limit", that is, when the mass of a star's hydrogen nucleus exceeds 1.44 times of the mass of the sun, it will not become a white dwarf, but will continue to collapse and become a star smaller and denser than a white dwarf, that is, a neutron star. 1939, American physicist Oppenheimer further proved that when the mass of a star's hydrogen nucleus is more than three times that of the sun, its own gravity will prevent light from escaping from the star.
With the accumulation of experience, the theory about black holes has matured. People have completely rejected this monster and come to believe it. By the 1960s, people had generally accepted the concept of black hole, and the mystery of black hole was gradually studied.
Strictly speaking, a black hole is not a "star" in the usual sense, but just a region of space. This is a field that is out of touch with our daily world. The black hole horizon separates these two regions. Outside the horizon, they can be connected with each other at any distance through optical signals. This is the normal universe in which we live. However, in the horizon, light cannot spread freely from one place to another, but all gather at the center, and the connection between events is strictly restricted. This is a black hole.
Inside the black hole, the tidal force is getting bigger and bigger as the object falls to the black hole. In the central area, gravity and tidal force are infinite. So in the center of the black hole, except for mass, charge and angular momentum, other properties of matter are lost, and atoms, molecules and so on will cease to exist! In this case, it is impossible to talk about what part a black hole is, and a black hole is a unity!
At the center of a black hole, all matter is squeezed into a geometric point with infinite volume approaching zero, and no powerful force can separate them. This is the so-called "singularity" state. General relativity can't investigate this, but it must be replaced by a new correct theory-quantum theory. Ironically, general relativity gave us a black hole, but it failed at the singularity of the black hole, and quantum theory took its place, but quantum theory and relativity were totally incompatible!
The development of the concept of the universe The development of the concept of the structure of the universe In ancient times, people's understanding of the structure of the universe was in a very naive state, and they usually made naive speculations about the structure of the universe according to their living environment. During the Western Zhou Dynasty in China, people living on the land of China put forward the early theory of covering the sky, thinking that the sky was like a pot, lying on the flat ground; Later, it developed into the later theory of covering the sky, which believed that the shape of the earth was also arched. In the 7th century BC, Babylonians believed that the sky and the earth were arched, with the ocean around the earth and the mountains in the center. The ancient Egyptians imagined the universe as a big box, with the sky as the lid, the earth as the bottom and the Nile as the center of the earth. The ancient Indians imagined that the disc-shaped earth was thrown on several elephants, and the elephants stood on the backs of huge turtles. At the end of the 7th century BC, Thales in ancient Greece thought that the earth was a huge disk floating on the water, covered with an arched sky.
It was the ancient Greeks who first realized that the earth was spherical. In the 6th century BC, Pythagoras thought that the most beautiful three-dimensional figure was spherical from an aesthetic point of view, and advocated that celestial bodies and the earth where we live were both spherical. This concept was later inherited by many ancient Greek scholars, but it was not until 15 19 ~ 1522 that F. Magellan of Portugal led the expedition to complete the first round-the-world voyage that the concept that the earth was spherical was finally confirmed.
In the 2nd century AD, Ptolemy put forward a complete geocentric theory. According to this theory, the earth is stationary at the center of the universe, and the moon, sun, planets and outermost stars are all rotating around the earth at different speeds. In order to explain the unevenness of the apparent motion of the planet, he also thinks that the planet rotates around its center in this round, and the center of this round rotates around the earth along a uniform wheel. Geocentric theory has been circulating in Europe for 1000 years. 1543, N. Copernicus put forward the scientific Heliocentrism, thinking that the sun is located in the center of the universe and the earth is an ordinary planet, orbiting the sun in a circular orbit. 1609, J. Kepler revealed that both the earth and the planets revolve around the sun in elliptical orbits, which developed the Heliocentrism of Copernicus. That same year, Galileo? Galileo took the lead in observing the sky with a telescope, and confirmed the correctness of Heliocentrism with a large number of observation facts. 1687, I Newton put forward the law of universal gravitation, which profoundly revealed the mechanical reasons for the motion of planets around the sun and gave Heliocentrism a solid mechanical foundation. After that, people gradually established the scientific concept of the solar system.
In Copernicus's image of the universe, the stars are just the light spots in the outermost starry sky. 1584, Giordano? Bruno boldly canceled this layer of stellar sky, thinking that stars are distant suns. /kloc-in the first half of the 8th century, Bruno's speculation was recognized by more and more people because of E Harley's self-development of stars and J Bradley's scientific estimation of the distant distance of stars. /kloc-in the mid-8th century, T. Wright, I. Kant and J. H. Lambert speculated that the stars and galaxies covered all day constituted a huge celestial system. Friedrich? William? Herschel first counted the number of stars in a large number of selected areas in the sky and the ratio of bright stars to dark stars with a telescope by sampling statistics. 1785, he obtained for the first time a flat structural map of the Milky Way with uneven outline and the sun as the center, thus laying the foundation for the concept of the Milky Way. In the next century and a half, after H. shapley discovered that the sun was not in the center of the Milky Way, J. H. Oort discovered the rotation and spiral arms of the Milky Way, and many people measured the diameter and thickness of the Milky Way, the scientific concept of the Milky Way was finally established.
/kloc-In the middle of the 0/8th century, Kant and others also proposed that there are countless celestial bodies like us (referring to the Milky Way) in the whole universe. The "nebula" that looked like a cloud at that time was probably such a celestial system. Since then, it has experienced a tortuous exploration process of 170 years. It was not until 1924 that E.P. Hubble measured the distance of the Andromeda nebula with Cepheid parallax method, which confirmed the existence of extragalactic galaxies.
Over the past half century, through the study of extragalactic galaxies, people have not only discovered higher-level celestial systems such as galaxy clusters and superclusters, but also expanded our horizons to the depths of the universe as far as 20 billion light years.
As early as the Western Han Dynasty, China had the concept of the evolution of the universe. "The True Sutra" points out: "There is a beginning and an end, a beginning and an end, and a husband has a beginning." He believes that the world has its opening time, its early opening period and its early opening period. Huainanzi? Astronomical training also specifically outlines the process of the world from the intangible material state to the chaotic state and then to the emergence and evolution of all things in heaven and earth. In ancient Greece, there was a similar view. For example, leucippus suggested that due to the rotating motion of atoms in a vacuum, light matter escaped into outer space, while the rest of the matter constituted spherical celestial bodies, thus forming our world.
After the concept of the solar system was established, people began to explore the origin of the solar system from a scientific point of view. 1644, R. Descartes proposed the vortex theory of the origin of the solar system; 1745, G.L.L Buffon put forward a theory of the origin of the solar system, which was caused by the collision between the great comet and the sun. 1755 and 1796, respectively, Kant and Laplace put forward the nebula theory of the origin of the solar system. The modern new nebula theory to explore the origin of the solar system is developed on the basis of Kant-Laplace nebula theory.
19 1 1 year, E. hertzsprung established the first color magnitude map of the cluster; 19 13, Bertrand? Arthur. William? Russell drew the spectrum-luminosity diagram of the star, which is also the Herro diagram. After obtaining this star map, Russell put forward the star evolution theory that stars start from red giants, first shrink to the main sequence, then slide down along the main sequence, and finally become red dwarfs. 1924, Arthur? Stanley? Eddington put forward the mass-luminosity relationship of stars; From 1937 to 1939, C. F. weizsacker and Bate revealed that the energy of stars comes from the nuclear reaction of hydrogen fusing into helium. These two discoveries led to the denial of Russell's theory and the birth of the scientific theory of star evolution. The study of the origin of galaxies started late. At present, it is generally believed that it evolved from primitive galaxies in the late stage of the formation of our universe.
19 17, a. Albert? Einstein established a "static, finite and unbounded" model of the universe with his newly founded general relativity, which laid the foundation of modern cosmology. 1922, discovered by G.D. Friedman, according to Albert? Einstein's field equation, the universe is not necessarily static, it can be expanding or oscillating. The former corresponds to the open universe, while the latter corresponds to the closed universe. 1927, Lemaistre also proposed an expanding universe model. 1929, Hubble discovered that the redshift of galaxies is directly proportional to their distance, and established the famous Hubble law. This discovery is a strong support for the expansion model of the universe. In the mid-20th century, G Gamov and others put forward a cosmological model of the Big Bang, and they also predicted that according to this model, we should be able to observe the low-temperature background radiation in space. 1965 The discovery of microwave background radiation confirmed the prediction of Gamov et al. Since then, many people regard the Big Bang model as the standard model of the universe. 1980, Gus of the United States further proposed the skyrocketing universe model on the basis of the big bang universe model. This model can explain most of the important observed facts known at present.
The research results of contemporary astronomy show that the universe is a celestial system with hierarchical structure, diverse material forms and continuous movement and development.
Modern astronomy reveals the origin and evolution of celestial bodies. Contemporary theories about the origin of the solar system hold that the solar system was probably formed by the gravitational contraction of a cloud of dust gas (primitive solar nebula) in the Milky Way galaxy 5 billion years ago (see The Origin of the Solar System). Stars are produced by nebulae, and their lives have gone through gravitational contraction stage, main sequence stage, red giant stage, late stage and dying stage. The origin of galaxies is closely related to the origin of the universe. The popular view is that 400,000 years after the Big Bang, the temperature dropped to 4,000 K, and the universe changed from a period dominated by radiation to a period dominated by matter. At this time, due to the gravitational instability caused by density fluctuation or the role of cosmic turbulence, protogalaxies gradually formed and then evolved into galaxy clusters and galaxies. The universe model of the Big Bang describes the origin and evolution history of our universe: our universe originated from a big bang 20 billion years ago, when the temperature was extremely high and the density was extremely high. With the expansion of the universe, it has gone through the evolution process from hot to cold, from dense to thin, from radiation to material, and it did not enter the stage of large-scale galaxy formation until1~ 2 billion years ago, and then gradually formed the universe we see today. 1980 proposed the skyrocketing universe model, which is a supplement to the thermal big bang universe model. It believes that in the very early stage of the universe, about 10-36 seconds after the birth of our universe, it experienced a skyrocketing stage.
The Creation of the Universe Some cosmologists believe that the most radical reform of the expansion model may be to observe that all matter and energy in the universe are generated from nothing. This view was not accepted by people before because there are many conservation laws, especially the conservation of baryon number and energy. However, with the development of the grand unified theory, the baryon number may not be conserved, and the gravitational energy in the universe can be roughly said to be negative, which accurately offsets the non-gravitational energy and the total energy is zero. So there is no problem that the known conservation laws prevent observing the evolution of the universe from scratch. This view of "making something out of nothing" includes two aspects in philosophy: ① ontology. It is wrong to think that "nothing" is absolute nothingness. This not only violates the known scientific practice of mankind, but also violates the inflation model itself. According to this model, the observed universe we study is only a small part of the whole skyrocketing region, and it is not absolutely "nothing" outside the observed universe. At present, the matter that observes the universe is transformed from the energy released by the false vacuum state. This vacuum energy is only a special form of matter and energy, and it is not created from absolute "nothing". If further, this vacuum energy comes from "nothing", then the whole observation universe comes from "nothing" in the final analysis, and this "nothing" can only be an unknown form of matter and energy. ② Epistemology and methodology. The concept of the universe involved in the inflation model is the concept of the universe in natural science. No matter how vast the universe is, as a limited material system, it also has its history of emergence, development and extinction. The inflation model combines the traditional big bang cosmology with the grand unified theory, and holds that the observed forms of matter and energy in the universe are not eternal, and their origins should be studied. It regards "nothingness" as an unknown form of matter and energy, and regards "nothingness" and "existence" as a pair of logical categories, and discusses how our universe has changed from "nothingness"-an unknown form of matter and energy to "existence"-a known form of matter and energy, which has certain significance in epistemology and methodology.
The origin of time and space Some people think that time and space is not eternal, but comes from a state without time and space. According to the existing physical theory, there is no "clock" and "ruler" to measure in the range of less than 10-43 seconds and 10-33 cm, so the concepts of time and space are invalid, and it is a physical world without time and space. This view that known space-time forms have their applicable boundaries is completely correct. Just as Newton's concept of time and space developed into a relativistic concept of time and space in history, it is inevitable to establish a new concept of time and space with the development of scientific practice today. Because the general theory of relativity fails within 10-43 seconds after BIGBANG, the quantum effect of gravity must be considered, so some people try to explore the origin of known space-time forms by quantizing space-time. All these works are beneficial, but we must not deny the objective existence of time and space as a form of material existence just because the development of human concept of time and space or the existing level of science and technology cannot measure the new form of time and space.
Since the 1960s, the relationship between human existence and the universe has emerged due to the proposal and discussion of the anthropic principle. According to the anthropic principle, there may be many universes with different physical parameters and initial conditions, but only universes with specific physical parameters and initial conditions can evolve into human beings, so we can only see a universe that allows human beings to exist. Anthropic principle uses human existence to constrain the possible initial conditions and physical laws in the past, reduce their arbitrariness and explain some cosmic phenomena, which is of certain significance in scientific methodology. But it has been suggested that the creation of the universe depends on the existence of human beings as observers. This view is debatable. Now, according to the inflation model, the states that were taken as the initial conditions by the traditional Big Bang model may have emerged from the very early evolution of the universe, and the evolution of the universe has almost become irrelevant to some details of the initial conditions. In this way, the above viewpoint of denying the objective reality of the universe by using the difficulties of initial conditions has lost its foundation. However, some people think that it is impossible to observe the overall structure of the universe because of the huge distance scale brought about by the skyrocketing. There are reasons for this concern, but if the inflation model is correct, with the development of scientific practice, it will be possible to break through the difficulties in human understanding.