Pay attention to the voice of the storm to improve the level of thinking
Guide
From the birth of the universe to the present, the error is not more than 1 second, what is the cold atomic clock?
This article is the fourth in a series of guest dialogue transcripts from the November 29, 2020 Video "Answers" Year-end Show Roundtable Forum "Gazing at the Earth – Looking Back at China and the World from the Perspective of the Universe". The first episode is seen in "Chinese Chips Are Not Useful? Not! Half of government units already use | The second episode of "Science and Technology Yuan Ren" see "The United States: China is too small to make manned spaceflight China: dictatorship does not obey the | The third episode of "Science and Technology Yuan Ren" can be seen in "How to Observe the Universe Before the Birth of the Universe?" Perhaps it depends on quantum mechanics | Technology Yuan Ren" Video Link: Watermelon Video: https://www.ixigua.com/6914173192080720388 This video was released on January 5, 2021 and has been viewed more than four million times
<h1 style="text-align: left;" > wonderful presentation:</h1>
【Episode 4】
Lin Baojun (Vice President of the Institute of Microsatellite Innovation of the Chinese Academy of Sciences, Chief Designer of the Beidou-3 Satellite): In addition, two scientists have been confused in my question, and we may take everyone who has studied physics to know that generally when we are in the laws of thermodynamics, one is the entropy increase theorem.
What do you mean? That is, the entropy of isolated systems can only increase and cannot decrease, but I think the phenomenon of the universe is very magical, in fact, the universe, including the galaxies they talk about, etc., is more and more regular, and celestial bodies are regular operations. For example, these planets revolve around the sun and so on, and I think this process is actually a process from disorder to order. What is the concept of disorder to order? It is the process of entropy reduction that is disordered. Entropy increase means to change from order to disorder, and nature becomes a process of entropy reduction, how is this explained to the laws of thermodynamics? Can you two explain it to me? Yuan Lanfeng (lecturer of "Science and Technology Yuan Ren" and associate researcher of the University of Science and Technology of China): I have a sentence to explain, that is, on the scale of the universe, the second law of heat is definitely still true, in fact, its entropy is still increasing, but because someone is expanding, so the entropy that its entire system can contain is increasing rapidly, so the entropy it can accommodate is also getting bigger and bigger, so we have not violated the second law of thermodynamics, in fact, we are in the local order phenomenon. But overall its entropy has become larger.
Lin Baojun: It is a local entropy reduction, but the overall entropy increases. Yuan Lanfeng: Yes, yes. Lin Baojun: The explanation is yes. Yuan Lanfeng: And one person who is very relevant is Prigojin, who is a Nobel Prize winner in chemistry, and he put forward the dissipation theory, the dissipative structure theory. In fact, he is also the doctoral supervisor of the teacher Chen Ping, who we appeared in yesterday. Chen Ping followed Prigojin to learn dissipative structure theory, but instead of studying chemistry, he studied economics, and he became an economist. But this dissipative structure theory means that if a system is far enough away from equilibrium, it is possible to spontaneously produce some ordered structure, but it itself becomes more ordered, but the price is that the environment becomes more disordered, and then the entropy of the whole increases.
But the advantage of this theory is that you can explain why some orderly results spontaneously arise in the world. The most typical is life, and the evolution of evolution eventually evolved life, but our life is at the cost of consuming a larger range of negative entropy, so the overall entropy still increases.
Cai Yifu (Professor, Department of Astronomy, University of Science and Technology of China): In fact, the evolutionary structure of our universe is also a sentence in my speech, why do we see these spots of red, red, blue and blue?
I don't know if any of the audience here knows why, or what effect he has brought to our universe today? Does anyone know? We know that our universe has hundreds of billions of stars in our galaxy, right? Then there might be hundreds of billions of galaxies like our own in the Milky Way, which is roughly an estimated scale. So imagine that our universe is full of all kinds of such structures, these are the structures of galaxies, and this structure is natural for everyone to ask a question, how did it come from, where did it come from? So I'm going to tell you that the structure of these galaxies can be traced back to these spots on these pictures of red, red, blue, and blue, because that's the temperature difference, and I'm going to tell you how big that the average temperature of today's universe is 2.725 Kelvin, and probably 273 Kelvin for ice, right? That is, about -270 degrees below the freezing point, which is about such a temperature, which is the average temperature of our universe. Above the average temperature, there is a temperature difference of about 10^(-5) to 10^(-6) Kelvin, which is the temperature difference seen by the cosmic microwave background radiation. Although the temperature difference is 5 to 6 digits after the decimal point compared to its background, this gap of 5 to 6 digits, which must be so small, eventually induces the generation of these structures that we see today. So we're really in some local range, like the Milky Way where it formed it has about 4 cantilevers, right? We live in Orion Arms, right? Then it just so happened that a galaxy like this in the solar system actually abounded in the Orion Arm. There happens to be a solar system that is generated, and then the solar system it is not particularly hot, it is not particularly cool, is it? So in this place there are some planetary systems, among which there is a planet, it is not so far, it is not so close, it just happens to be our earth, and on the earth there is just such a number of intelligent life births, that is, we humans.
We may live in a quadrangular spiral galaxy (the Milky Way) that has a bright and symmetrical central bar. | Image credit: XING-WU ZHENG AND MARK REID Bar and Spiral Structure Legacy Survey/Nanjing University/ Center for Astrophysics, Harvard and Smithsonian (Milky Way chart and illustration)
Map of the Structure of the Milky Way: Using multiple radio telescopes, astronomers have made thousands of hours of observations of the Milky Way, measuring the distances between some celestial structures. The figure is the best aerial view of the structure of the Milky Way ever. The data shows the four main spiral arm structures that surround the center of the Milky Way. Our sun (which astronomers see as the center of the four-quadrant mapping coordinates) orbits the Milky Way, around a circle that takes about 212 million years. Near the sun's orbit, there is a smaller spiral arm (blue). In the future, studies using radio telescopes in the Southern Hemisphere may reveal most of the other structures in the fourth quadrant that are not currently directly observed. | Mapping: Elena Hartley
This is a formation process that is highly disordered to orderly. But you can imagine that the price behind such a process is the price of the birth of so many useless solar or star systems. Lin Baojun: You just said that it is close to absolute zero, and I will tell you another story. In fact, there are many ways to reach absolute zero, in fact, we scientists have thought of a way to what is it? With a laser to form a network, in fact, what is the temperature, the temperature characterizes the state of thermal movement of molecules, so that the molecules gather in this pile so that it can not move, as long as it hits this laser to bounce back, it is in this circle, using this principle is close to absolute zero, we are now using the state of close to zero degrees, we have made a cold atomic clock, this cold atomic clock is better than the hydrogen atomic clock I am talking about today, good and many. In this principle, we have already ascended to the heavens on Tiangong-2 and achieved very good results. I am happy to tell you that we are going to hit the Beidou satellite next year, and I will go up this laser cold atomic clock. Originally, I said rubidium clock, because its drift is relatively poor, it is not only long (period) stability (fixed) is relatively poor, drift is relatively poor, about 1 hour we have 1 hour, 1 to 2 hours to inject once. But our hydrogen clock is one or two orders of magnitude better than it, it is injected once an hour or two, and I can bet once every 1 to 2 days. To what extent can this laser cold atomic clock go now? The result of my betting data once in 30 years is similar to the result of my 1 to 2 hours betting, so after I type it, after I calibrate the time once, it does not have to move again, this time is an absolutely accurate time, so our time can take a step. So in terms of commanding heights technology, maybe in the near future we can cross a big step again, so as far as we just said that it is close to absolute zero, I will tell you a story that is, in fact, many natural phenomena can be used to serve mankind.
Yuan Lanfeng: I can finally comment on it, Teacher Li just mentioned the cold atomic clock, in fact, in this regard, China is now the most advanced, and we will soon launch one, that is, for our Beidou system, it will achieve accuracy from the birth of the universe to now is 13.8 billion years of time error is not more than one second, this is now the most advanced clock of mankind, this is built with quantum precision measurement technology. So when you use quantum mechanics, it will have this effect. And just now Teacher Cai said that the Milky Way has 4 cantilevers, when do you think this knowledge was discovered? In fact, this year (2020), just a few months ago, it was announced that a group of scientists from China and the United States were collaborating on the discovery. So you see, it seems that a very rudimentary knowledge is actually something that we have only recently discovered, which shows that we are in the midst of a tide of scientific and technological progress.
<h1>Further reading:</h1>
How to observe the universe before the birth of the universe? Perhaps it depends on quantum mechanics | Technology Yuan Ren
Chinese chips are useless? Not! Half of government units already use | Technology Yuan Ren
United States: China is too small to engage in manned spaceflight China: Dictatorship does not obey | Technology Yuan Ren
What is the right way for Chinese chips? ——Yuan Lanfeng, November 29, 2020 Watching Video Answers Year-end Show Speech Wu Ji: The Nobel Prize has been awarded to foreign "space science" many times, when will China catch up? | Technology Yuan Ren
2020 "Answer" year-end show, what questions to go on together! | Yuan Lanfeng
In 2020, what is our new mission? It's all in the "Answer" year-end show! | Video Studio
Lin Baojun: If you don't dare to walk in front of the United States, how can China get rid of the "stuck neck"|? Technology Yuan Ren
If the universe didn't originate from the Big Bang, how did it come | about? Technology Yuan Ren Plus No. 25
Background: Yuan Lanfeng, Ph.D. in Chemistry, University of Science and Technology of China, Associate Researcher of Hefei National Research Center for Microscale Physical Sciences, University of Science and Technology of China, President of science and Technology and Strategic Wind and Cloud Society, keynote speaker of "Science and Technology Yuan Ren", Standing Committee Member of Anhui Science and Technology Association, Standing Director of China Youth New Media Association, Selected as one of the Top Ten Science Communication Figures of "Dianzan 2018 Science Popularization China", Weibo @ Hu Bugui of China University of Science and Technology, Zhihu @ Yuan Lanfeng (https://www.zhihu.com/people/yuan-lan-feng-8).
Editor-in-Charge: Zhu Yang