Who can tell you something about space?

The word "universe" probably originated from the famous philosopher Mozi in ancient China (about 468-376 BC). He used "Yu" to refer to the space in all directions, and "Zhou" to refer to the time from ancient times to the present. Together, it refers to everything in the world, no matter how big or small; Past, present or future; To approve or not to approve ... In short, everything is everything.

From a philosophical point of view. People think that the universe has no beginning, no end and no end. However, we are not going to discuss this abstruse concept in depth, so let's leave it to philosophers to study. We might as well squint and use our existing science and technology to talk about the universe that we can understand and observe. People call it "our universe" or "total galaxy".

In the west, the word universe is called universe, universe and space; In English; Russian name is кocMoc, German name is kosmos, and French name is cosmos. Are derived from the Greek κoσμoζ. The ancient Greeks believed that the universe was created to produce order from chaos, and the original meaning of κoσμoζ was order. But in English, the more commonly used word for "universe" is Universe. This word has something to do with universitas. In the Middle Ages, people called universities a group of people who acted in the same direction and goal. In the broadest sense, universitas also refers to a unified whole composed of all ready-made things, that is, the universe. The universe and the universe often express the same meaning, but the difference is that the former emphasizes the sum of material phenomena, while the latter emphasizes the structure or construction of the whole universe.

In Chinese, "Yu" stands for up and down four directions, that is, all the space, and "Zhou" stands for all the time, that is, all the time. Yu: infinite space, and Zhou: infinite time. So the word "universe" has the meaning of "all time and space". Linking the concept of "universe" with time and space embodies the wisdom of the ancient people in China.

According to the latest observation data, the farthest galaxy observed by people is 65.438+0.3 billion light years. That is to say, if a beam of light is emitted from the galaxy at a speed of 300,000 kilometers per second, it will take 654.38+03 billion years to reach the earth. This distance of 65.438+0.3 billion light years is the universe we know today (2008). More specifically, the universe as we know it today, or its size, is a spherical space with the earth as the center and the distance of 65.438+0.3 billion light years as the radius. Of course, the earth is not really the center of the universe, and the universe is not necessarily a sphere. It's just limited to our current observation ability, and we can only know this extent.

In this spherical space with a radius of1300 million light years, there are about1250 million galaxies that have been discovered and observed, and each galaxy has hundreds to trillions of sun-like stars. So as long as you do a simple math problem, it is not difficult for you to know how many stars there are in the universe we have observed. In such a vast universe, the earth is really a drop in the ocean and insignificant.

Astronomers have always wondered how big the universe is, just like us. Recently, the American Space Network reported that after hard calculation, astronomers found that the universe is extremely huge, with a length of at least 65.438+056 billion light years. "Such a discovery about the size of the universe is obviously based on the premise that the universe is spherical and finite." Daming Chen, a researcher at the National Astronomical Observatory of China, said in an exclusive interview with reporters, "For a long time, there has been such a debate in the field of cosmology, whether the universe is spherical, saddle-shaped or flat." Zhang Yue, an associate professor at Beijing Normal University, said: "The international mainstream cosmology generally believes that the universe is flat and infinite." So, where does the debate around the universe come from? What makes sense? The most common view is that after the Big Bang, the universe was born. "According to the most influential Big Bang theory in modern cosmology, our universe was produced by a very small point explosion about 65.438+0.37 billion years ago, and the universe is still expanding." Researcher Daming Chen said, "This theory has been confirmed by a large number of astronomical observations." This theory holds that in the early days of the birth of the universe, the temperature was very high. With the expansion of the universe, the temperature began to drop, producing neutrons, protons and electrons. Since then, these elementary particles have formed various elements. These particles attract and fuse with each other, forming larger and larger clumps, and gradually evolving into galaxies, stars and planets. Life phenomena have appeared on individual celestial bodies, and finally human beings who can understand the universe have been born. Is the universe spherical and finite? "The idea that the universe is spherical has existed for a long time, although it is not the mainstream of the international cosmology community." Daming Chen said, "Every time it is mentioned, it will attract people's attention, because this view is very strange." One of the most obvious examples is the universe model established by American mathematician Jeffrey Wilkes not long ago: a mirror maze of limited size, shaped like a football. The model of "shaped like a football" shocked the scientific community, because this theory claimed that the universe produces an "illusion" without boundaries because this limited space reflects itself endlessly through the "circle" effect. Wilkes believes that people think that the universe is infinite because the universe is like a mirror maze, and light shuttles back and forth, giving people the illusion that the universe is infinitely extended. This amazing inference was later included in New Scientist magazine and widely circulated among the people as a kind of "strange talk".