according to the theory of the universe, the universe we observed was concentrated in a very small, extremely high temperature and extremely dense singularity at the early stage of its gestation. From 15 billion to 2 billion years ago, the singularity exploded, and the birth history of our universe began.
.1 seconds after the Big Bang, the temperature of the universe was about 1 billion degrees. The main forms of matter are electrons, photons and neutrinos. After that, the material diffused rapidly and the temperature dropped rapidly. One second after the big bang, it dropped to 1 billion degrees. Fourteen seconds after the big bang, the temperature was about 3 billion degrees. After 35 seconds, at 3 million degrees, chemical elements began to form. The temperature keeps falling and atoms keep forming. The universe is filled with gas clouds. Under the action of gravity, they formed a star system, and the star system has undergone a long evolution and has become today's universe.
the sum of material phenomena. In a broad sense, it refers to the infinite variety and eternal development of the material world, and in a narrow sense, it refers to the largest celestial system observed in a certain era. The latter is often called hubble volume, our universe, and now it is equivalent to the "master galaxy" in astronomy.
in February p>23, NASA announced their research results about the age of the universe to the world. According to its published data, the age of the universe should be 13.7 billion years old. In November 23, the international astrophysics research group declared that the exact age of the universe should be 14.1 billion years old. The formation of the earth is about 4.5 billion years ago.
etymological study: The word universe was first used in China's ancient books by Zhuangzi's Theory of All Things. The meaning of "Yu" includes all directions, such as all places in the east, west, north and south. "Zhou" includes past, present, day and night, that is, all different specific times. At the end of the Warring States Period, Shi Jiao said: "The four directions are up and down, and the past is the present." "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 whole objective real world. Concepts equivalent to the universe include "heaven and earth", "Gankun" and "Liuhe", but these concepts only refer to the space aspect of the universe. The word "Zhou He" in Guanzi refers to time, and "He" refers to space, which is the closest to the concept of "universe".