In the vast universe, it is difficult to give birth to a civilization, and even 10 thousand solar systems may not be able to give birth to a civilization.
But does this mean that civilization is rare in the universe?
No, on the contrary, there are many civilizations in the universe.
There is only one reason, and that is because there are so many galaxies in the universe.
There are hundreds of billions of stars in the Milky Way alone, and there is at least one planet around each star.
Even if 1 100 million star systems can give birth to 1 100 million cosmic civilizations, there are at least 1000 such civilizations in the Milky Way.
And giant planets like the Milky Way need a whole100000 to form supercluster.
Is the supercluster the boundary of the universe?
No, only within the range of human observation, there are hundreds of millions of such supercluster in the universe.
However, beyond the maximum range of human observation, it is still unknown how many supercluster there are.
How many civilizations will there be in the universe? Do the math yourself.
Then why haven't we seen an alien civilization?
Because human technology is so weak that we have no ability to explore the boundaries of the solar system.
Expecting such human technology to discover aliens is no less than expecting a primitive man who can only make canoes to cross the Atlantic to discover America.
Most civilizations born in the universe will be locked on their home planet until the day when the planet dies.
Those lucky few who have developed interstellar travel technology will expand rapidly, occupying 99% of the universe resources.
We haven't seen them yet. The big reason may be that the universe is too big. Before they could fly here, they occupied a galaxy. I don't know how many billions of years it will take.
The technological span of crossing the intergalactic gap may be no less than that of crossing the Atlantic Ocean and flying out of the solar system.
And there are more giant galaxies like the Milky Way than sand in the universe.
We don't know how many civilizations in the universe have started interstellar travel, but I know that if such a spaceship reaches the earth, they will treat us like Australian kangaroos, and the technological gap is too great.
We can't count on the savior, our own powerful technology, as the patron saint of mankind to the future.
Facing the future and science, we should have the courage and impulse to go forward bravely, and we should always be curious about science.
Human science and technology is not achieved overnight, but accumulated bit by bit. It is the transmission of science and technology that has enabled mankind to step into today's civilization from the period of ignorance.
The country is strong when young people are strong, and science and technology are prosperous when young people are prosperous.
In a few billion years, the Milky Way will collide with Andromeda, causing countless stars to run out of order and collide with each other like billiards.
The possible ecological changes on the earth will make it impossible for human beings to survive until then.
If mankind has not invented the technology of space travel by then, then mankind will disappear into the history of the universe as if it had never appeared.
The current technology of human beings is still far from the real interstellar civilization, and we still need the efforts of countless generations to get human beings into space.
Teenagers are the core of human knowledge transmission. The real hope of human civilization lies in transmitting science to teenagers, developing their interest in scientific exploration, and forming an atmosphere of respecting knowledge and advocating innovation.
China Association for Science and Technology launched the "Popular Science Caravan" activity, which has been carried out for 229,000 times so far, making great contributions to popular science education for young people.
In September last year, Tencent Youth Popular Science Exhibition reached a cooperation with the "Popular Science Caravan", launched a large number of popular science videos and articles to go deep into remote mountainous areas with the motorcade, and built a "star cinema" to show popular science short films in a three-dimensional immersive way, bringing a "mobile version" of the popular science exhibition to serve young people all over the country.
In 2020, the "popular science caravan" will cover 32 provinces across the country, and the number of young people will reach160,000 every year.
Popularization of science requires the joint efforts of all sectors of society. Fortunately, many non-governmental forces in China are constantly pushing this matter, ensuring the transmission of the fire of science and technology in China.
Curiosity is the driving force of civilization.
In 2065438+2009, Tencent Youth Science Club and the famous academic journal Science launched a list of scientific highlights, and1.20 thousand teenagers voted online to select the most wanted scientific topics.
The final winners are as follows.
What everyone wants to see most is a black hole.
On June 5438+1October 65438+February, 2020, Tencent and Tsinghua University held the Youth Science Conference 2020, inviting eight famous scientists and popular science scholars in four basic science fields to introduce the latest achievements of human exploration of the mysteries of the universe with the theme of "Crossing schwarzschild radius".
The scientists involved are all scientific and technological elites.
It's hard to get these tech giants together, but it's wonderful to get together and give lectures.
The progress of science comes from curiosity, and what attracts human curiosity most is the vast universe.
Although human beings are very small relative to the universe, we are still a member of the spirit of the universe. As long as we explore the universe tirelessly, we may not stand on the top of the universe.
Schwarzschild radius is the conclusion drawn by German scientist karl schwarzschild on the basis of Einstein's "general relativity".
When a star collapses to schwarzschild radius, its gravity will be so great that even light cannot escape, and eventually it will become a black hole.
To what extent should human science and technology develop to leapfrog schwarzschild radius?
This is an expectation that mankind can have a bright future.
1. The first human black hole photo.
Since schwarzschild radius put forward it, black holes have been a human guess, and many people don't admit the existence of black holes. It was not until 20 19 that humans finally took the first photo of a black hole.
This picture of a black hole was taken by the "Vision Telescope" project team, which is composed of scientists from more than ten countries, with the goal of observing supermassive black holes.
The so-called horizon is the visible range of a black hole. On the surface of this horizon, even light cannot escape. If you enter this horizon, you are completely blocked by the world. All the events in the horizon will not be seen by anyone in this universe, and there is no way to perceive them by any means.
But we know that there must be a supermassive black hole in the center of each galaxy, and the whole galaxy runs under the gravity of this black hole. There is such a giant black hole in the center of the Milky Way, which is about 4 million times the mass of the sun.
At the scientific conference, Avery, the head of the event horizon telescope project team, brought us the story behind the black hole shooting.
It is difficult to photograph a black hole because it is completely invisible. It is almost impossible to find a pure black space in the dark universe.
We can't observe black holes directly, but we have other ways to observe them indirectly.
Around some black holes, a lot of gas and dust are active. They run around black holes at high speed, are heated to billions of degrees, and emit a lot of radiation, some of which can be observed by the earth in the wireless band!
We can't observe the giant black hole in the center of the Milky Way galaxy because of the occlusion of the line of sight, but some black holes can.
After observing at eight observation points on four continents 10 years, and summarizing a large amount of data, humans finally took a concrete picture of the black hole in the center of Virgo A galaxy (M87), which is 6.7 billion times the mass of the sun and about 53.5 million light years away.
The M87 black hole is not the largest black hole in the universe, or even the largest black hole discovered by human beings. I chose it just because it is the easiest to shoot.
2. China discovered a stellar black hole far beyond the theoretical limit.
The study of black holes is not only the patent of foreigners.
Liu Jifeng, China discovered the largest stellar black hole so far at 20 19 by using the Guo Shoujing Telescope (LAMOST) independently developed by China.
After monitoring more than 3,000 celestial bodies in a Kepler sky area (K2-0) for two years, he found that the trajectory of a type B star was very abnormal.
After calculation, it is confirmed that there must be a black hole around this type B star, with about 60~80 solar masses, named LB- 1.
This is the largest black hole found in the star system, which refreshes human understanding of the upper limit of the quality of stellar black holes. According to the current model, there should not be such a massive black hole in a small star system, and the mass of LB- 1 far exceeds the theoretical upper limit.
This discovery forced human astronomers to rewrite the formation model of interstellar mass black holes, and won the "Scientific Exploration Award" for Liu Jifeng in 20 19.
Besides black holes, China has also taken a solid step in space exploration.
3. China's space exploration plan for the next decade.
Ouyang Ziyuan, academician of China Academy of Sciences and chief scientist of Chang 'e Project, introduced China's grand space exploration plan to us.
At the end of 2020, the Long March 5 rocket will continue to be launched, and it will go to the moon to sample and return to make technical preparations for manned landing on the moon.
In mid-2020, China's Mars probe will be launched on schedule, because it is not necessary to go to Mars, because the distance between the Earth and Mars is constantly changing, and the appropriate launch window will only appear once every 26 months. I won't go in June and July this year, but I will go in two years and two months, so China people must grasp this window.
In the next 10 year, China will have a huge space exploration plan, not only to explore Mars and Jupiter, but also to explore the asteroid belt of the solar system and the Kuiper belt of Wang Xing.
This is a grand plan. Hope to succeed and cheer for China!
4. The largest cryoelectron microscope research center in the world.
In addition to technological breakthroughs in space, China's achievements in the field of cryoelectron microscopy are unparalleled in recent years.
Low temperature electron microscope is a great technological invention, which won the Nobel Prize in 20 17 years. It enables human observation technology to achieve near-atomic resolution, can enlarge objects by hundreds of thousands of times, and can completely preserve the three-dimensional shape of protein.
/kloc-in the 7th century, the Dutch Levin Hooke invented the microscope, which opened the door to the microbial world. The cryoelectron microscope gave human beings the ability to decipher the structure of protein.
According to Professor Wang Hongwei, Dean of School of Life Sciences, Tsinghua University, Tsinghua University has built the world's largest cryoelectron microscope research center.
Professor Shi Yigong, former dean of the School of Life Sciences of Tsinghua University, has made a series of important international research achievements in the field of biological protein analysis with the help of cryoelectron microscopy technology, which makes China's scientific research strength in this field catch up with the United States and Germany, showing a tripartite confrontation.
In addition to these hard-core scientific introductions, Dr. David from Grandpa Chemistry; Mark; Founder of the "funny" Nobel Prize; Tim; , editor-in-chief of the famous academic journal Science; Zhang Shengyu, head of Tencent Quantum Lab, also gave a wonderful speech from the perspective of popular science among teenagers.
The mystery of the universe has always been fascinating.
In a sense, vigorously promoting popular science is as important as front-line scientific research tasks. Only a steady stream of new generation of scientific research teenagers can bring future and hope to China.
Every scientist's childhood is "lit up" by popular science, thus embarking on the road of exploring the unknown.
With the continuous research of these three teenagers, mankind finally discovered the "schwarzschild radius" and finally "lit up" the black hole.
This talented "scientific conference" is of great significance. Although the meeting is small, it plays an important role.
I hope more children in China can be "lit up" by this Expo, so that they can "light up" the future of China and mankind in ten, twenty and thirty years.
Teenagers' hope of crossing schwarzschild radius.