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? 6? 1 Galileo was the first to observe the sky with a telescope, and the correctness of Heliocentrism was confirmed by 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.

In Copernicus's image of the universe, the stars are just the light spots in the outermost starry sky. 1584, Giordano? 6? 1 Bruno boldly canceled this layer of star sky and thought that the star was a distant sun. /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? 6? 1 William? 6? 1 year, Herschel first used a telescope to count the number of stars in a large number of selected areas in the sky and the ratio of bright stars to dark stars. 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.

/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. 6? 1 zhenxun pointed out: "there is a beginning, there is a beginning without a beginning, and there is a husband without a beginning without a beginning." It believes that the world has its opening time, its pre-opening period and its pre-opening period.

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? 6? 1 Arthur? 6? 1 William? 6? 1 Russell drew the spectrum-luminosity diagram of the star, that is, 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? 6? 1 Stanley? 6? 1 Eddington proposed 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.

19 17, a. Albert? 6? 1 Einstein established a "static, finite and unbounded" model of the universe by using his newly established general theory of relativity, which laid the foundation for modern cosmology. 1922, discovered by G.D. Friedman, according to Albert? 6? 1 Einstein field equation, the universe is not necessarily static, it can be expanded or oscillated. 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.