The top and bottom are shapeless, how to test them?
It's dark, but who can do it?
Feng Yi just likes it. How would he know?
Obviously secretly, but when?
The combination of yin and yang, what is this?
Hey, it's nine times. Which one is it?
…………
2300 years ago, Qu Yuan (340 BC-278 BC), a great poet in China, questioned a series of questions about the formation of heaven and earth and the structure of the universe in his famous long poem Tian Wen, expressing Qu Yuan's concern, thinking and strong interest in exploring the universe himself and many people in past dynasties.
Astronomy tells us that the earth where human beings live does not exist in isolation in the universe, but depends on and restricts other celestial bodies. In order to understand the position of human beings in the universe, their origin, evolution, future prospects and how to avoid disadvantages, we must understand the spatial distribution, characteristics and * * * of various celestial bodies and their celestial bodies systems in the universe from near to far, and understand the origin and evolution of the universe. To this end, we humans have experienced a long and difficult exploration process and will continue to explore in depth.
First, the ancient world outlook
There are three main world views of China's ancient ancestors: covering the sky, revealing the night, and muddy the sky.
Gaitian theory appeared at the end of Yin Dynasty and the beginning of Zhou Dynasty. People at that time intuitively thought that "the sky is round like a cover and the place is like a chessboard". Therefore, this theory of covering the sky is also called "the theory of heaven and earth". According to this theory, the sky is round and the earth is square, so the two cannot be connected. Therefore, it is proposed that heaven and earth are separated by 80 thousand miles and supported by eight pillars. The theory of covering the sky is a primitive view of the universe, which has many obvious loopholes and cannot explain the rise and fall of the sun, the moon and the stars. Thus, the later Huntington theory came into being.
Huntian theory began in the Warring States period. Huntington's theory holds that the earth is spherical, with a spherical dome outside, and the earth floats on the water in the sky. During the Three Kingdoms period, a man named Xú Zhēng also described the formation of heaven and earth in this way: "Heaven and earth are chaotic like chickens, and Pangu was born in them for 8,000 years. The heavens and the earth are open, and the yin is the earth. Pangu is in it, and it changes nine times a day. God is in heaven and sacred to the earth. The sky is ten feet high and the ground is ten feet thick. So eight thousand years old, the number of days is extremely high, the number of places is extremely deep, and Pangu is extremely long. So I went to Wan Li. " It can be seen that our ancients had the idea of expanding heaven and earth very early.
Michelle Ye's theory is a kind of cosmology summarized by the ancients through observing the phenomenon of day and night. Michelle Ye said that the sky is not a kind of entity, it looks high and far, with no end. The sun, the moon and the stars are just glowing gases, running freely in the ethereal space. It can be seen that Michelle Ye's theory is a simple concept of infinite universe.
About 1900 years ago, the ancient Greek astronomer Ptolemy (AD 90 168) collected the achievements of ancient Greek astronomy and put forward "geocentric theory" in his masterpiece Astronomy. He thinks that the earth we live in is static, at the center of the universe, and celestial bodies revolve around it. The closest to the earth is the moon, followed by mercury, Venus, the sun, Mars, Jupiter, Saturn, the starry sky and the highest sky. This is the so-called cloud nine thought. He also used this theory of circle, even wheel and eccentric circle to explain the movement of the moon, sun and planets. Ptolemy's geocentric theory summed up the ancient Greeks' understanding of the structure of the universe.
Religious theology in medieval Europe believed that "geocentric theory" conformed to the doctrine, and took it as the theoretical pillar of God's creation of the world, raising it to a sacred height, which led to geocentric theory occupying a dominant position in Europe for 1400 years, which seriously hindered the development of scientific thought and the birth of scientific cosmology, which Ptolemy himself did not expect.
Second, the creation and development of Copernicus' "Heliocentrism"
In A.D. 1543, the Polish astronomer Copernicus (A.D. 1473- 1543) published his scientific masterpiece "The Operation of Celestial Bodies" on his deathbed. He put forward "Heliocentrism" in this book. Copernicus thought that the earth was not the center of the universe, but the center of the moon. The sun is the center of the universe. Planets such as the earth revolve around the sun, and the order from near to far is Mercury, Venus, Earth, Mars, Jupiter and Saturn. The Sunday rotation of the sky is caused by the earth's rotation around its axis every day. The annual apparent movement of the sun is not its own movement, but the earth revolves around the sun once a year. The anterograde and retrograde phenomena of other planets can be explained by the same motion of the earth and planets around the sun.
Heliocentrism of Copernicus revealed that the earth is an ordinary planet, which fundamentally denied the religious myth that "the earth is arranged in the center of the universe by God" and shook people's worship of the church. Astronomy and even the whole natural science began to get rid of the shackles of religion and be liberated from theology. Copernicus' Heliocentrism is a great leap in the history of human exploration of the universe. It sounded the death knell of the dark Middle Ages and showed the beginning of modern European civilization, which was of epoch-making significance. This naturally led to the opposition and suppression of conservative religious forces, and those who maintained, disseminated and developed Copernicus Heliocentrism were brutally persecuted by the Inquisition.
Bruno (A.D. 1548 1600), a famous Italian thinker, not only popularized Copernicus' theory, but further believed that the sun is not the center of the universe, but one of thousands of ordinary stars. He also believes that the sun is by no means the only star with a planetary system, and there are many habitable worlds in the universe. 1592, the Inquisition arrested Bruno, interrogated him cruelly for eight years, and burned the unyielding fighter who insisted on the truth alive in Rome Garden Square on February 1600.
Soon after, the German astronomer Kepler (A.D. 157 1 1630) discovered the three laws of planetary motion. He pointed out that the orbit of the planet around the sun is an ellipse, and the sun is located at a focus of the ellipse. 16181621year, he published an introduction to Copernicus astronomy, supplemented and revised Copernicus' theory with his own findings, and further perfected and developed Copernicus' theory.
Galileo Galilei (A.D. 1564 1644), the founder of modern experimental science, was the first person to explore the starry sky with a telescope. He found that Jupiter has four satellites, which proves that the planet is the center of its own satellite, and it revolves around the larger center of operation-the sun. The sun is just an ordinary star in the universe, so the sun may also rotate around a larger center of operation. This is the first time to prove that there may be different levels of cosmic systems in the universe. 1632, Galileo published a collection of conversations between Ptolemy and Copernicus, which proved the correctness of Copernicus' theory with a series of conclusive evidence, but Galileo was sentenced to life imprisonment by the Holy See. It was not until June 1979 1 1, that is, more than 300 years after his death, that the Pope had to rehabilitate his own injustice.
It is the core problem of solar system theory to explain why planets revolve around the sun and run in the way pointed out by Kepler's law. Until the famous British scientist Newton (A.D. 1642 1727) discovered gravity, this problem has not been solved. According to legend, in 1665, Newton was inspired by the fall of an apple and discovered the law of universal gravitation. Subsequently, a Newtonian mechanical system with the law of universal gravitation and the three laws of motion of objects as the core was established. He used the law of universal gravitation to deduce Kepler's three laws of planetary motion, which provided theoretical proof for the laws of planetary motion, and established the concept of scientific solar system by establishing Copernicus' Heliocentrism on a solid theoretical basis.
Third, human's vision of observing the universe is constantly expanding.
178 1 year, the British German scientist Herschel discovered Uranus, which is the seventh planet outside Saturn's orbit in the solar system. It was not long before Uranus was found to be a little abnormal. 1August 3, 8461August, Le Ye Wei, who has been engaged in the study of Uranus' abnormal motion for many years at the Paris Observatory, wrote a paper "On the planets that make Uranus run abnormally, how to determine their mass, orbit and current position". He calculated the orbital elements of unknown planets. After the publication of the paper, this calculated unknown planet was really discovered by Berlin astronomer Gail on September 25th, 1846. The observed position differs from that calculated by Le Ye Wei by less than one degree. The discovery of Neptune, the eighth planet in the solar system, aroused great enthusiasm at that time. It is different from the previous discovery of new celestial bodies by direct observation with naked eyes or telescopes. It was discovered by scientific wisdom and computing power, and it was discovered at the tip of a pen. Proved the incomparable power of Newtonian mechanics. At this point, Copernicus's theory won a complete victory.
1930, 23-year-old American astronomer Tom Bo discovered Pluto, which has long been regarded as the ninth largest planet in the solar system and has now been downgraded to a dwarf planet. At this point, people's understanding of the radius of the solar system has expanded from the initial 10 astronomical unit to 40 astronomical units (note: the astronomical unit is the average distance between the sun and the earth, and one astronomical unit is about1500,000 km).
Although it has been speculated that all the stars in the sky are distant suns since16th century, it is further speculated that they may form more than one larger star system, but this needs to be proved by systematic observation and research. The real systematic observation and study of the stellar world began with Herschel, the discoverer of Uranus and known as the "father of stellar astronomy". Herschel, who is diligent in astronomical observation, counted the stars in the whole day according to the sky and magnitude respectively, and confirmed that many stars we saw, including those in the Milky Way, were in a limited group of stars called the Milky Way. He used the largest telescope at that time to find that some nebulae that were once considered "starless" were originally composed of many small stars. In fact, they are star systems outside our milky way galaxy, which are often called extragalactic galaxies. This kind of nebula is also called extragalactic nebula to distinguish it from the gas nebula in the Milky Way.
Through the continuous efforts of Herschel and his successors, we finally figured out the structure of our galaxy. Our Milky Way galaxy is a spiral galaxy with hundreds of billions of stars, most of which are concentrated in a flat disk called a silver disk, which is shaped like a discus. Our sun is not in the center of the Milky Way, but near the central plane of the Milky Way, that is, galactic plane, about 30,000 light years away from the center of the Milky Way. There are four spiral arms in the silver plate, where gas, dust and young stars are concentrated. Our sun is on the third spiral arm. All the celestial bodies in the galaxy revolve around the center of the galaxy. In addition to rotation, the Milky Way as a whole moves towards the direction of Kirin at a speed of 2 14 km per second. The sun travels around the center of the Milky Way at a speed of 220km/s, and it takes 225m years to make a revolution, which is called the cosmic year.
At present, radio telescopes can receive radio waves from celestial bodies 1000 billion light years away. Hubble telescope and other high-performance observation instruments launched into space have expanded the radius of our human vision to about10 billion light years. Astronomers usually refer to the galaxies and intergalactic matter contained in the currently observable space as the total galaxy. The total galaxy is the largest material system we can observe at present, which contains hundreds of billions of star systems and a large number of intergalactic materials. The Milky Way, where our sun is located, is just one of hundreds of billions of star systems in the whole Milky Way. The universe generally mentioned in scientific research refers to the part of the universe that we can observe at present, that is, the whole galaxy. It is also called our universe.
Fourthly, the establishment of the origin theory of BIGBANG.
At the beginning of the 20th century, the German-American scientist Einstein (A.D. 1879 1955) established the special theory of relativity, and then the general theory of relativity. Meanwhile, some scientists created quantum mechanics. This provides a scientific theoretical basis for us to re-understand the macro world and the micro world. 19 17 years, Einstein calculated according to the equation of general relativity, and concluded that the universe is either expanding or contracting.
1929, American astronomer Hubble (A.D. 1889 1953) analyzed the light emitted by other galaxies and found that most galaxies have left us, and their retrogression speed is directly proportional to their distance from the earth. This important discovery, called Hubble's Law, confirms that our universe is expanding. The discovery of the expansion of the universe made modern cosmologists re-study the origin and evolution of the universe, which led to the birth of the thermal big bang theory, which was supported by a series of observational facts and accepted by most scientists. According to the measured expansion speed of the universe, our universe contracted to a point about 65.438+038 billion years ago. According to the thermal big bang theory, our universe is the Big Bang that originated here and now. In other words, our universe has a beginning in time and space. It evolved according to the laws of nature and gradually evolved into the vast world we see today.
Verb (abbreviation of verb) The journey of human beings to explore the universe has a long way to go.
Compared with our universe, the earth we live in and ourselves are very small. There are endless mysteries in our universe. But we humans are never satisfied with our ignorance of the universe, but constantly explore the mysteries of the universe with our wisdom and efforts.
Tsiolkovsky, the founder of the three-stage rocket theory and a middle school teacher in the former Soviet Union, put it well: The earth is the cradle of mankind, but mankind will not stay on the earth forever, but will explore space. At first, they will carefully go beyond the scope of the atmosphere, and then boldly conquer all the space near the sun.
196 1 year, the former Soviet astronaut Gagarin rushed out of the earth's atmosphere in a spaceship, realizing the first space flight of mankind. 1969, American astronauts realized the first human flight to the moon. Starting from 1972, humans began to launch some detectors that can fly out of the solar system and explore extraterrestrial civilization. Some of these probes have now reached the edge of the solar system.
1970 China launched the first artificial earth satellite. On June 5438+1October 65438+May, 2003, China successfully launched the first manned spaceship "Shenzhou 5", sent China astronaut Yang Liwei into space, circled the Earth 14 and returned safely the next day, realizing the dream of flying for a thousand years, marking that China became the third space power in the world capable of carrying out manned space flight. Since then, China has successfully launched manned spacecraft for many times, achieving the feat of multi-person and multi-day space flight and spacewalk.
In addition, China has successfully launched the "Chang 'e" lunar exploration satellite four times since 2007, among which the lunar rover carried by "Chang 'e IV" achieved the first landing of the human lunar rover on the back of the moon, and made some important discoveries. At present, China is vigorously building a space station, which is expected to be completed in 2022. In view of the fact that the International Space Station, which originally operated in space, can no longer work in orbit, China Space Station will become the only space station that works in orbit.
Undoubtedly, the industrious, brave and intelligent people of China will make greater contributions to mankind in the risky and shocking journey of manned space exploration of the universe.