The sum total of material phenomena. In a broad sense, it refers to the infinitely diverse and eternally developing material world, and in a narrow sense, it refers to the largest celestial body system that can be observed in a certain era. The latter is often called the observable universe, our universe, which is now equivalent to the "total galaxy" in astronomy.
Etymological investigation
The earliest use of the word universe in ancient Chinese books is "Zhuangzi·Equality of Things". The meaning of "Yu" includes all directions, such as all locations from east to west, north to south. "Cosmos" includes the past, present, day, and night, that is, all different specific times. Shi Jiao in the late Warring States period said: "The four directions above and below are called Yu, and the past and present are called Universe." "Yu" refers to space, "Zhou" refers to time, and "Universe" is the unity of time and space. Later, the word "universe" was used to refer to the entire objective reality world. Concepts equivalent to the universe include "Heaven and Earth", "Cosmos", "Liuhe", etc., but these concepts only refer to the spatial aspect of the universe. The word "zhouhe" in "Guanzi" refers to time and "he" (i.e. "Liuhe") refers to space, which is closest to the concept of "universe".
In the West, the word universe is called cosmos in English, кocMoc in Russian, kosmos in German
and cosmos in French. They are all derived from the Greek κoσμoζ. The ancient Greeks believed that the creation of the universe produced order from chaos. The original meaning of κoσμoζ is order. But the word more commonly used to mean "universe" in English is universe. This word is related to universitas. In the Middle Ages, a group of people acting together in the same direction toward the same goal was called a universitas. In the broadest sense, universitas
also refers to the unified whole composed of all ready-made things, that is, the universe. Universe and cosmos often mean the same thing, but the difference is that the former emphasizes the sum of material phenomena, while the latter emphasizes the structure or structure of the overall universe.
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. They usually made decisions about the structure of the universe based on their own living environment. Childish speculation. During the Western Zhou Dynasty in China, people living on the land of China put forward the early theory of sky-gap, which believed that the sky was like a pot, upside down on the flat earth; later it developed into the later theory of sky-gap, which believed that the shape of the earth was also arched. . In the 7th century BC, the Babylonians believed that the sky and the earth were arched, with the earth surrounded by oceans and mountains in the center. The ancient Egyptians imagined the universe as a large box with the sky as the lid, the earth as the bottom, and the Nile River in the center of the earth. Ancient Indians imagined that the disk-shaped earth was carried on several elephants, and the elephants stood on the backs of huge turtles. At the end of the 7th century BC, Thales of ancient Greece believed that the earth was a huge disk floating on the water. , covered with an arched sky.
The first people to realize that the earth is spherical were the ancient Greeks. In the 6th century BC, Pythagoras started from the concept of aesthetics and believed that the most beautiful of all three-dimensional figures was the sphere. He advocated that both the celestial bodies and the earth we live on are spherical. This concept was inherited by many ancient Greek scholars later, but it was not until 1519-1522, when F. Magellan of Portugal led an expedition to complete the first circumnavigation of the world
The concept that the earth is spherical was finally confirmed.
In the 2nd century AD, C. Ptolemy proposed a complete geocentric theory. This theory holds that the earth is motionless in the center of the universe, and that the moon, sun, planets, and the outermost stars are all revolving around the earth at different speeds. In order to explain the uneven apparent motion of the planet, he also believed that the planet rotates around its center on an epicycle, and the center of the epicycle rotates around the earth along the deferent wheel. The geocentric theory has been circulating in Europe for more than 1,000 years. In 1543, N. Copernicus proposed the scientific heliocentric theory, which believed that the sun is located at the center of the universe, and the earth is an ordinary planet orbiting the sun in a circular orbit. How was the universe formed (1.1 Human The universe we know)
15 billion years ago, the entire universe was dark. Suddenly one day, an earth-shaking big explosion occurred in the universe. How could the universe explode? Scientists compare the universe to a ball. The material that makes up this ball is a very dense material, and its temperature is extremely high. If the current Earth is compared to a ping-pong ball, then the diameter of the sphere in the universe is like a football field. At this time, there are only substances in the form of basic particles such as neutrons, protons, electrons, photons and neutrinos. Due to the high temperature and the extreme instability of these substances, the "ball" of the universe is constantly expanding, like a big blow. The balloon will inflate "whirring". When the age of the universe was 10-44 seconds, the temperature reached as high as 1032°C. A moment later, that is, after 10-34 seconds, the universe suddenly "inflated", just like a big balloon suddenly being blown violently. There was a huge explosion, which expanded the universe 1029 times in an instant.
The power and speed of its explosion are astonishing, and the temperature also drops rapidly as the universe sphere explodes and expands. 0.01 seconds after the big bang, the temperature of the universe dropped to 1011°C; 0.1 seconds later, the temperature dropped to 300°C. 100 million degrees; after 13.8 seconds, the temperature further dropped to 3 billion degrees; at 35 minutes, the temperature had dropped to 300 million degrees. By the time 300,000 years after the Big Bang, the temperature had dropped to 3,000°C, the universe began to become transparent, and chemical elements began to be formed during this period.
For 15 billion years, the universe has been expanding and its temperature has been gradually decreasing. At the same time, living things have been produced and reproduced. This is like drawing a map to scale, condensing the 15 billion-year history of the universe into one year, giving us an extremely intuitive and interesting "cosmic calendar":
January 10, With the Big Bang, the universe emerged; on May 1, the vast Milky Way was born; on September 9, the solar system came into existence; on September 14, the earth was formed. On September 24, primitive life appeared on the earth; on November 12, green plants emerged from the ground; on December 26, more advanced mammals appeared. At 0:22:30 on December 31, primitive humans stood on the earth; at 23 minutes and 46 seconds, Peking Man created fire; at 23 minutes and 59 seconds, Chinese history continued to the Spring and Autumn Period...Song Dynasty; at 24 minutes, the world entered the The modern society that continues to this day. It can be seen that human history is only an extremely brief moment in the time of the universe.