Black holes can intermarry.

Now, what enters the black hole is stellar dust, gas, light, spaceships with robot astronauts, and garbage to be converted into energy. In any case, trapped matter only increases the mass of the black hole itself, and at the same time expands its radius and surface. If the mass doubled, the radius doubled, and the area of the horizon increased by four times. Will it continue to grow forever? Hocking first made a categorical answer: since it is proved that the black hole will not shrink again, it will continue to increase indefinitely. As it is continuous, the increase is gradual. But there is a special case, that is, two black holes may be in contact with each other and collide. In the process of attracting each other, a black hole enters another black hole. The two black holes become a single black hole, and all the components of the two black holes are preserved. The larger single black hole may collide with another black hole, and so on, thus producing a black hole of mass and volume. It is believed that in the process of collision, about 1/1000 of the black hole's static energy is released, and it is emitted to the cosmos in the form of gravitational waves. Like speed and light, its area is expanding and the entropy of the black hole increases. In other words, the internal chaos is growing, that is, information about inhaled substances can not be used or remedied, as if a computer accidentally messed up the letters of a newly written article. So there are only three messages that can be described in black holes: mass, angular momentum (the rotation of black holes) and charge. Wheeler compared this information to bald head with only three hair. We could not understand what the material was in. Based on these three kinds of information, we can classify black holes: the Schwarzschild black hole with no angular momentum and no charge. It has the characteristics of "singularity" and "Horizon"; the Kerr black hole with angular momentum but no charge; and the black hole with angular momentum and charge. It can also be distinguished from the origin of black holes. But the latest classification is based on "color".It seems a bit ridiculous. How can a black hole without a beam of light be colored? In fact, the colors mentioned here are not the colors of the usual red, blue, green, and so on, but are used to distinguish the different colors of quarks. Quarks are smaller elementary particles that make up protons and neutrons. For our sky physicists, the pursuit of different colors of black holes in the process of tracking infinitesimal to infinity and from infinity to infinity begins.

Black holes are colored.

Scientists have always thought that it is impossible to understand the nature of matter that is absorbed by a black hole, but the latest theories hold that black holes can provide information in that way, because black holes emit particles like gluons. Gluon is the transmitter of quark binding and quark is the basic particle of matter. Because quarks and gluons are distinguished according to "color", the same way can be used to partition black holes according to the type of gluons they discharge. This graph represents a series of gluons (colored pellets) discharged from a black hole.

Magical black hole journey

If there is magic to make an astronaut drill into the black hole safely by spaceship, he will tell us a lot of amazing things. Since the scene is a rotating black hole, what he tells is probably a layer of energy. All the movements in that area rotate according to the rotation of the black hole. After drilling into the area, the spacecraft may keep up and down, coming and going from this area. Of course, there must be enough fuel.

If our stubborn astronaut is determined to go further and to drill into the second interface called the horizon, he will find that under certain conditions, because of the strong centrifugal force, the spaceship will stay there for ever to spin and no longer sink, but there is no possibility of it coming out. This situation is similar to the large cylinder rotating in the open amusement park. It squeezed people on the wall of the cylinder, so long as the cylinder was rotated, people could not move.

The black hole itself is a mysterious object. It is like a runaway computer, which can swallow any information and destroy the contents of anything that falls into it. The physical properties of black holes that we can collect are three, mass, angular momentum and charge. The rest is a bunch of useless information, which is of no help in identifying the material properties inside the black hole.On the point of singularity, that is, the central density of black holes is infinite, Einstein's general relativity and the derived laws of space and time will all be invalid and no longer have the right of "citizen".

But Stephen Hawking, the great black hole theorist and British astrophysicist, has found valuable information about the appetite of black holes in the field of vision by clever escaping. The more matter a black hole suck in, the more its mass will increase, and the more it expands its horizon. It's such a fast energy exchange scene that it's hard for nature to detect.

Compared with the rotated Schwarzschild black hole, the internal structure of the rotating Kerr black hole is much more complicated. Its singularity is a circle lying on the equator rather than a point. If an astronaut passes through the ring, it will reach the opposite area, where there is a white hole. It is like a catapult, which can immediately launch the astronauts to the outer world, which is another universe. In addition, there are second horizons within the real horizon of the Kerr black hole. The spherical bread is surrounded by "singularities" protected by circular singularities. The region between the inner and outer boundaries is not affected by singularity. With the increase of the angular momentum of the black hole, the expansion of the inner horizon and the contraction of the outer horizon make the two tend to coincide.

If you jump into a black hole

If two spacecrafts sail to a spinning black hole before and after space, the first spacecraft is ready to sacrifice itself bravely, and what kind of scene will you see when you observe the performance of the second spacecraft? Imagine that on the first spacecraft is an intelligent robot. When approaching the horizon, that is, the black hole boundary where there is no return point, the robot astronauts walk out of the spacecraft to meet the death. He will be attracted by the gravitational attraction of the nearest part of the black hole, broken into two halves, and then unconsciously swallowed up in the singular point (the center of the black hole) that just disappeared near the space-time. The spacecraft was torn to pieces by the powerful gravitational force before it was engulfed. How big is this attraction? For a black hole with a mass equal to the sun, a 2 meter tall person must bear the acceleration of gravity equivalent to 1 billion times the earth's surface. In order not to fall into a black hole, you must rely on the thrust of a sufficiently large engine to park the spacecraft in a safe distance or around a black hole. It seems to you that the spaceship ready to sacrifice seems to have used endless time to get close to the black hole, and the speed of the spacecraft is slower and slower, changing the color at the same time, but before you can see the spacecraft is still at rest, the spaceship will disappear from the eyes. The reason for this phenomenon is that, according to the theory of relativity, the passage of time depends on the speed of the observer.

In this black hole journey, we see that a rotating black hole is like a rotating disc with holes in it. It has two layers of interface, one of which is the horizon, and the outer layer is called the "static limit" or the infinite redshift surface. Between these two interfaces is a special area called "energy level".On the static boundary, time is "frozen", radiation is redshifted indefinitely, the spacecraft stays at a fixed point, the spaceship that the robot astronaut sees on the spacecraft will no longer change, and the black hole will rotate rapidly under his feet. If we go beyond the static boundary and enter the energy level, the spacecraft will be dragged into the rotating motion.

The energy layer has an amazing characteristic. As the British mathematician Roger Penrose (Roger Penrose) pointed out, the energy entering into it can become negative. We might as well imagine this object as a person with energy debt. When a black hole captures this object, the energy of the black hole is not increasing but decreasing, because the black hole must "repay" the energy debt owed by its prey.

Returnees Dr. Zhang Shuangnan: astrophysicist who broke into the black hole of the universe.

Returnee Zhang Shuangnan in Queshan County of Henan province is a world-famous scientist studying black holes in the universe. In 1999, he was named one of the ten Chinese scientific and technological achievements by overseas Chinese media such as "world daily".
Student Era
Zhang Shuangnan was born in an intellectual family in Queshan County in December 1962. From primary school to high school, Zhang Shuangnan's academic record has been excellent. Especially in high school, many times won the first prize in the physics competition held in the county and county. Zhang Shuangnan was most grateful for his physics teacher in high school, who benefited from the teacher's inspiration and patient guidance, which made him slowly fall in love with physics. This laid a solid foundation for his study at Tsinghua University and later in physics research.
In 1979, Zhang Bi Nan entered the Engineering Physics Department of Tsinghua University with excellent results, which made him dream of going to university. This is also the resumption of the college entrance examination since the first student in Tsinghua University in the old district.
After graduating from university in 1984, Zhang Shuangnan was admitted to the Graduate School of high energy physics, Chinese Academy of Sciences. In the meantime, his advisor is known as "Chinese Mrs. Curie" famous physicist He Zehui academician. With the careful nurturing of He Zehui and other teachers, Zhang Shuangnan made rapid progress in academic research. In only two years, he passed the Ph.D. examination and became a Ph.D. candidate.
Challenge black hole
In 1986, a joint scientific research project was launched by the Institute of high energy physics, Chinese Academy of Sciences and the Department of physics of SOUTHAMPTON UNIVERSITY, University of Southampton. After the completion of the project, Zhang Shuangnan was left in the UK to pursue his doctorate, and received a scholarship from University of Southampton and a British Overseas Scholarship. He received his doctorate in University of Southampton in 1989.
At the end of 1989, Zhang Shuangnan applied for postdoctoral research from University of Pennsylvania in the United Kingdom. After completing the post doctoral research, he went to astrophysics research at the Marshall Flight Center of the US space and space agency in 1992. Zhang Shuangnan went to the Marshall space flight center and entered a new stage in the study of astrophysics. At that time, his research results were constantly shaking up in the astrophysics field, which made many famous scientists in the world look up to the young scientist from China. In the meantime, he invented a new method of image processing, which was published in 1993 by the first author in the most authoritative English Nature magazine in the world. In 2000, Zhang Shuangnan published the latest achievement of black hole research in the American science magazine with the first author.
Zhang Shuangnan used his method of image processing to discover second "quasars" (a black hole binary system) in the galaxy and his colleagues, and named it GRO J1655-40. Zhang Shuangnan later discovered several other black hole binary systems with his colleagues. He and his colleagues won the "collective achievement award" issued by NASA by virtue of their outstanding achievements in this field.
In order to measure the rotational nature of the black hole, Zhang Shuangnan and two other Chinese scientists Cui Wei and Chen Wan put forward a method to measure the rotation of the black hole in 1997. First, we measured the rotation of a group of "black holes" and got the tangential evidence of the "black hole" rotation. The publication of "the astrophysics", an authoritative academic journal in the United States, has aroused great interest in the academic field.
Feelings of children
Although Dr. Zhang Shuangnan has lived in the United States for more than ten years, but as a Chinese nation, he loves his motherland and loves his hometown. He has not forgotten that he is a Chinese. He said, "I belong to the motherland forever." Since 1996, he has returned to China many times to report his achievements in science. He has been lecturing at the Chinese Academy of Sciences, Tsinghua University, Peking University, University of Science and Technology of China, Nanjing University, Nanjing University, Institute of science and technology, and other universities for academic reports, making academic exchanges and contributing to the promotion of science and technology in China.
He returned to his hometown to visit his teachers, relatives and friends, and to learn about the development of science and technology and education in his hometown. He went to school in his hometown to give lectures, stimulate students' interest in learning, encourage students to study hard, and strive to win glory for the country. To train scientific research personnel in China, he has recruited many PhD students and visiting scholars from the mainland to guide them in scientific research.

Returnees Dr. Zhang Shuangnan: astrophysicist who broke into the black hole of the universe.

Returnee Zhang Shuangnan in Queshan County of Henan province is a world-famous scientist studying black holes in the universe. In 1999, he was named one of the ten Chinese scientific and technological achievements by overseas Chinese media such as "world daily".
Student Era
Zhang Shuangnan was born in an intellectual family in Queshan County in December 1962. From primary school to high school, Zhang Shuangnan's academic record has been excellent. Especially in high school, many times won the first prize in the physics competition held in the county and county. Zhang Shuangnan was most grateful for his physics teacher in high school, who benefited from the teacher's inspiration and patient guidance, which made him slowly fall in love with physics. This laid a solid foundation for his study at Tsinghua University and later in physics research.
In 1979, Zhang Bi Nan entered the Engineering Physics Department of Tsinghua University with excellent results, which made him dream of going to university. This is also the resumption of the college entrance examination since the first student in Tsinghua University in the old district.
After graduating from university in 1984, Zhang Shuangnan was admitted to the Graduate School of high energy physics, Chinese Academy of Sciences. In the meantime, his advisor is known as "Chinese Mrs. Curie" famous physicist He Zehui academician. With the careful nurturing of He Zehui and other teachers, Zhang Shuangnan made rapid progress in academic research. In only two years, he passed the Ph.D. examination and became a Ph.D. candidate.
Challenge black hole
In 1986, a joint scientific research project was launched by the Institute of high energy physics, Chinese Academy of Sciences and the Department of physics of SOUTHAMPTON UNIVERSITY, University of Southampton. After the completion of the project, Zhang Shuangnan was left in the UK to pursue his doctorate, and received a scholarship from University of Southampton and a British Overseas Scholarship. He received his doctorate in University of Southampton in 1989.
At the end of 1989, Zhang Shuangnan applied for postdoctoral research from University of Pennsylvania in the United Kingdom. After completing the post doctoral research, he went to astrophysics research at the Marshall Flight Center of the US space and space agency in 1992. Zhang Shuangnan went to the Marshall space flight center and entered a new stage in the study of astrophysics. At that time, his research results were constantly shaking up in the astrophysics field, which made many famous scientists in the world look up to the young scientist from China. In the meantime, he invented a new method of image processing, which was published in 1993 by the first author in the most authoritative English Nature magazine in the world. In 2000, Zhang Shuangnan published the latest achievement of black hole research in the American science magazine with the first author.
Zhang Shuangnan used his method of image processing to discover second "quasars" (a black hole binary system) in the galaxy and his colleagues, and named it GRO J1655-40. Zhang Shuangnan later discovered several other black hole binary systems with his colleagues. He and his colleagues won the "collective achievement award" issued by NASA by virtue of their outstanding achievements in this field.
In order to measure the rotational nature of the black hole, Zhang Shuangnan and two other Chinese scientists Cui Wei and Chen Wan put forward a method to measure the rotation of the black hole in 1997. First, we measured the rotation of a group of "black holes" and got the tangential evidence of the "black hole" rotation. The publication of "the astrophysics", an authoritative academic journal in the United States, has aroused great interest in the academic field.
Feelings of children
Although Dr. Zhang Shuangnan has lived in the United States for more than ten years, but as a Chinese nation, he loves his motherland and loves his hometown. He has not forgotten that he is a Chinese. He said, "I belong to the motherland forever." Since 1996, he has returned to China many times to report his achievements in science. He has been lecturing at the Chinese Academy of Sciences, Tsinghua University, Peking University, University of Science and Technology of China, Nanjing University, Nanjing University, Institute of science and technology, and other universities for academic reports, making academic exchanges and contributing to the promotion of science and technology in China.
He returned to his hometown to visit his teachers, relatives and friends, and to learn about the development of science and technology and education in his hometown. He went to school in his hometown to give lectures, stimulate students' interest in learning, encourage students to study hard, and strive to win glory for the country. To train scientific research personnel in China, he has recruited many PhD students and visiting scholars from the mainland to guide them in scientific research.

The greedy black hole was originally a star.

In fact, the concept of black hole has been put forward for more than 200 years. In 1783, John Michel, the British Job, first proposed the existence of a star that is large enough and compact enough. The gravity of Michel is so strong that even light cannot escape. A few years later, Pierre Simon de Laplace, a French scientist, put forward a similar view with Michel in his book "world system". But interestingly enough, the third and later versions of the book never mentioned it again. Maybe he thought the idea was too absurd. More than a century later, the German astronomer Karl Schwasi (Karl Schwarzschild) solved the first rigorous solution of Einstein's general relativistic equation in 1916. This solution indicates that there may exist a large class of celestial bodies, known as "black holes" after 60s. The first time we saw the black hole was in 1971. At that time, we discovered a strong X ray pulse source from the Swan region by the Uhuru, a small astronomical satellite launched in December 12, 1970. It was named the Swan X L, which is the first black hole confirmed by the body. Since then, black holes have become a hot topic in astrophysics.Today, we have learned a lot about the formation process of black holes. Simply speaking, black holes are massive stars that collapse after supernova explosion, that is, their very strong contraction.We can think of a black hole as a huge "Grinder" that pulverized the incoming material. Its center is known as the "grinding point", the so-called "singularity". In this "singularity", the laws of science and our ability to predict the future have failed. The boundary of a black hole is called the "Horizon". This is an interface with no return. As long as it crosses this interface, it falls into the interior of the black hole. But assuming that someone unfortunately falls into it, the first thing he sees is the light captured by the black hole, and these rays spiral into the gravitational vortex.

Giant stars collapse to form black holes

After a steady youth and middle age, a star will enter the old age and eventually die. The star, which is at least 10 times larger than the sun, will expand in old age and become a red giant, and then explode - supernova explosion. The outer layer of material is thrown into space, and the core of the center collapses suddenly and violently under the action of gravity, forming a black hole.

Space and time distorted by black holes

According to Einstein's general theory of relativity, when there is no gravity effect, time and space (grid in Figure) is flat (see left), but when there is gravity, time and space will be bent (see chart).The right side of the diagram shows a serious distortion of the space-time around the black hole due to the strong gravitational attraction of the black hole. A black hole with the same mass as the sun has a radius of only 3 kilometers, while the sun's radius is 696 thousand kilometers.

Scientists say aliens may live inside the black hole.

Alien homeland? According to one scientist, some black holes can have complex internal structures, allowing photons, particles and even planets to move around their central singularities. The outer ring in this image represents a planet running on orbit, while the inner colored ring represents the photon in motion.

This artistic imagination depicts the strong tidal force exerted by black holes on surrounding objects. The right side of the picture is originally a star. Because of the gravitational effect of the supermassive black hole nearby, it was eventually torn apart.

Sina Technology, according to the British Daily Mail, the idea that aliens live in a black hole may not be so absurd as it might be. According to one scientist, some black holes can have complex internal structures, allowing photons, particles and even planets to move around their central singularities.

Singularity is the region where the space-time becomes infinitely large in a black hole. However, Professor Vee Che Lev, VyacheslavDokuchaev, believes that in certain areas of the black hole, time and space will appear again as long as the conditions are right.

He said that as long as the mass of a rotating black hole is large enough, it will weaken its strong tidal force beyond its horizon. The horizon is considered to be the boundary of a black hole. In this range, no matter, including light, can escape.

Scientists have long established that photons can indeed exist in periodic orbits that are stable inside such a charged black hole. But Professor Dao Qia also believes that within the Cauchy horizon of a black hole, particles and even planets can be allowed to exist. Cauchy's horizon is a concept introduced by Hocking. In this area, the dimension of time and space began to change.

He said that the material in this area was prevented from being destroyed by the black hole, and the light and heat were obtained from the surrounding photons passing round, and the energy was obtained from the singularity of the black hole.

Professor Du qqia, who works at the Nuclear Energy Research Institute of the Russian Academy of Sciences in Moscow, believes that his view can prove the possibility of the existence of self sufficient extraterrestrial life. He said: "I think this area of the black hole separated by two strict horizons and the outside world is a very suitable area. As long as technology is developed enough, advanced civilization may do this and live inside the massive black hole of the core of the galaxy, and the external world can not observe them completely because of the blocking of the horizon.

Earlier this year, scientists discovered that the mass of black hole M87 is almost two times that of previous estimates. M87 is the largest and most distant black hole observed at present, which is about 50 million light-years away from the earth. Researchers say that the formation of such a supermassive black hole may have been combined by hundreds of smaller mass black holes at a certain stage in the past. In contrast, the black hole in the core region of our galaxy is 1000 times smaller than it is.

The latest research finds that the black hole is only 1600 light-years away from the earth.

The distance between a black hole and the earth is only half the amount that people used to think.

Astronomers have discovered that the distance between a black hole and the earth is only half the amount that people used to think. This is the first time to accurately measure the distance between the earth and the black hole. But if you hear that it is 7800 light-years away from Earth (1 light years equivalent to 5 trillion and 800 billion miles, 9.3341952 * 1015 meters) before you want to hide it, you may breathe a little easier. However, the nearest black hole is only 1600 light-years away from our green home.
A black hole is a region of space. Nothing can escape the attraction of a black hole, even if the light is no exception. The point where there is no return is called "event horizon". The researchers said that the analysis of the researchers showed that the black hole was born from supernovae (Star explosions), moving at about 25 miles (40.23 kilometers) per second in space. The star eventually collapsed and formed a point of zero volume and density, known as "singularity".

The gravity around the singularity is so strong that even if the light breaks in, there will be no return. Therefore, no information can be transmitted to us from this area. For this reason, we call it black hole, whose surface is called the surface of the black hole. The research team led by Peter Jokel (Peter Jonker) of the Netherlands Institute for Space Research (Institute), by measuring the radio waves emitted by the black hole, and studying the V404 Cygni accompanying its dying star, Cygnus, has finally made a breakthrough, measuring the distance between the black hole and the earth.
They use the radio telescope around the world to measure the distance between the earth and that black hole. Astronomical distance is difficult to calculate because it involves a very wide area.However, they often use the Trigonometric Parallax method to measure. The method of trigonometric parallax is to compare the apparent motion of nearer stars with the apparent motion of more distant stars by comparing the observed data of 6 months before and after the final result.

The research team applied this method to black holes and stars V404 Cygni, which is gradually absorbed by black holes. By this method, the distance between the black hole and the earth is measured to be 7800 light-years, with a measuring error of less than 6%. They believe that due to previous scientists underestimate the adsorption of interstellar dust, overestimate the distance between the black hole and the earth, the error is 50%.

Dr Jokel said: "through these information, we can better understand the evolution of black holes.For example, we hope to answer the following questions: directly from the collapse of stars, there is no difference between the black hole of supernovae and the black holes evolved through supernovae (short intermediate stars). We hope that we can get an unexpected surprise for the study of the latter group of black holes. The black hole formed in this way will move faster in space later. " Researcher James Miller Jones (James Miller-Jones) said: "now we are trying to apply the same measurement method to several other black holes."

Related information:
Hooligan black hole
Wandering black holes
Is there a black hole or a galaxy?
Scientists have discovered the largest black hole to date
Scientists discovered a rare medium quality black hole

The final fate of black hole: Big Bang

In the assumption that the black hole is increasing, the life of a black hole will never stop. But a warning stop was made by the same Hocking, who compared black holes to a constantly inflated balloon. In 1976, Hocking published in the journal Nature that black holes would evaporate until they finally explode.

Today, this theory has been widely recognized. It is thought that it is possible to see that the last flicker of a black hole is the Y ray emitted from the final explosion of a black hole observed in high-energy electromagnetic waves.

Black holes are always greedy, and the end of them is simply devouring something that can not be digested: a particle with negative energy. The particles with negative energy come from the energy layer with the particles that provide positive energy, but those particles that provide positive energy are pushed outside the black hole, while the black holes swallow the particles with negative energy, so they have to make up their debts by consuming the cost of their own energy. As a result, the mass of the black hole decreases, and a continuous evaporation process begins. As the black hole gets smaller and hotter, its energy dissipated in space. Finally, the old predator exploded and disappeared.

The size of the black hole is different and the degree of evaporation is different.

Now let's move on to the topic of not talking about black holes produced by collapsing stars.Scientists believe that the universe was created immediately after the big bang, and at that time there were many tiny black holes: they were sized like a proton but weighed hundreds of millions of tons. The massive black hole with high temperature is the ideal place for evaporation.

Now, most of these micro black holes have disappeared, but some other explosions are taking place. According to astrophysicists, it is possible to take advantage of a tiny black hole evaporating instead of our sun. The mass of the micro black hole is 1 / 1000 of the moon's mass, but its diameter is only 0.0005 millimeters.

The temperature of such a miniature black hole is thousands of degrees, close to the surface temperature of the sun, and the energy of continuous radiation can last for 10 years. If compared with the known age of the universe for 15 billion years, the time is long enough. If compared with the life span of the sun for 10 billion years, it can be said to be a permanent energy source.

Be cold, be a little cold.

Each of us has the concept of temperature. We know that hot things are high in temperature and cold in things are low in temperature. But besides, what else can temperature tell us?

In fact, when we feel that the object is hot, the atoms inside it move more rapidly, and when we feel cold, the movement is slower. Our bodies turn the speed of this disorder into a sense of heat and cold, and the thermometer is used to express the speed of this movement by numerical value.

So when we heat an object, it is actually moving the atoms in the body faster. For solids, the random motion of atoms is a reciprocating vibration, and for gas, the atom behaves like a ball, flying around. These atoms are constantly colliding with other atoms around, so some fly fast and others fly slowly. Is temperature changing and fluctuate? Unable. Because for a group of atoms, the velocity of each atom varies within a range, but their average speed is constant. If an atom slows down, there must be an increase in the speed of another atom. Therefore, temperature actually describes the average velocity of a whole atom composed of many atoms. Unlike most people, physicists prefer to use a temperature scale different from the Celsius temperature used in our daily life. This is called absolute temperature, and the unit is K. The absolute temperature of 1 degrees is the same as that of Celsius. The difference is only in the selection of zero.

If you keep lowering the temperature of the gas atoms in a box, these atoms will eventually cease to move. This is the minimum temperature limit that an atom can achieve, which we call absolute zero (0k). If there is a thermometer with absolute temperature and Celsius temperature at the same time, the Celsius temperature corresponding to absolute zero is minus 273.15 degrees (273.1 degrees Celsius).

Is there a temperature in the world that is absolutely zero? In fact, outer space should be the coldest place in nature, but the temperature there is also 3k, which is 3 degrees higher than absolute zero. This is a powerful evidence of the big bang that has ever happened. (the prevailing view is that the background radiation originated in the early days of the thermal universe. The measured results of 3K microwave background radiation generally coincide with theoretical predictions). And humans do better in refrigeration than in nature. Scientists can create a refrigeration system that can reduce the temperature of an object by 3K almost a century ago. Then a big leap has reduced the temperature to 1/1000 (10 ^-3 ) Connell and weman reduced the temperature of a very small sample to 1/1000000000 (10). ^-9 This marked a step forward for mankind in refrigeration technology.

The most difficult to detect and significant waves.

According to general relativity, when an object accelerates, it will interfere with the gravitational field and radiate gravitational waves, which is like throwing a stone onto the surface of a calm water. Therefore, any object radiates gravitational waves all the time, which is everywhere in the universe. For example, when the earth moves around the sun, it will give off gravitational waves. As a result, the earth loses energy and gradually moves closer to the sun along the helix. In that case, why are we not aware of its existence?

The answer is that gravity is actually the weakest force we know. The electromagnetic force that keeps the atom as a whole is 1000 trillion billion billion than that of gravity, that is, 10 ^Thirty-nine ) times. The only reason why we feel gravity is that the earth is so huge that the gravitational pull of countless particles that make up the earth is cumulative. But gravitational waves are the weakest and least noticeable waves in nature, and they do not produce any effect that we usually perceive.For example, when the earth revolves around the sun, the energy lost by the radiation gravitational wave is only about 0.001 watts, so it is close to the distance from the sun in billions of years. If 50 billion asteroids, 1 kilometers in diameter, hit the earth at a speed of 10 kilometers per second, the gravitational wave energy generated can only light a light bulb. But no one can live to see this result.

The key equipment of Virgo

The upper left is the "Virgo" detector. It will send gravitational waves to the signal. The upper and middle plans and the upper right picture are two parts of the super shock absorber. The shock absorber will isolate the equipment from external disturbances.

Of course, more massive mass redistribution will produce stronger gravitational waves, such as a star collapsing into a black hole, or two stars colliding, which may produce gravitational waves that we can detect. But even so, it is extremely difficult to detect gravitational waves directly, and it can be said to be a great challenge to human intelligence.

Secrets of refrigeration Kingdom

Refrigeration is not just for food preservation. There are 5 specialized companies in the United States specializing in keeping the remains of the deceased at -200 C. Many people have a hope before life, that is, they can revive one day with the help of some kind of medicine. James Bedford, a psychologist who chose to sleep in liquid nitrogen, was killed by cancer in 1967 when he was 73 years old. Since then dozens of people have followed his example, and thousands of others have signed a contract for "refrigeration" after death. These bodies are headed down in storage, so that once the automatic control system fails, the head will become the last thawing part.

Unlike the average person, the refrigerator is not a machine for making cold air, but a device for absorbing heat in food. It uses the liquid called "refrigerant" to extract the heat from food and transfer it to the outside of the refrigerator. Refrigerants flow through a series of refrigerators, including 3 basic components: compressors, condensers and evaporators, and repeat the same cycle of refrigeration (similar to the Kano cycle).

In addition to a few environmentally-friendly fridges, most refrigerators used in household refrigerators are mostly Freon (mainly two chloro two fluormethane), which is stored in special containers for refrigerators. When the refrigerator starts running, the motor drives the compressor to start working, and inhales the Freon vapor at low pressure and normal temperature, and compresses it into high temperature and high pressure steam (about 10 atmospheres).

The Freon vapor at high temperature and high pressure is sent to the condenser after leaving the compressor. Condenser is a tube that has been bent many times. It is called "serpentine tube", which is usually installed behind the fridge. Because the temperature of Freon vapor entering the condenser is higher than that at room temperature, the heat is emitted outward through the wall of the serpentine tube, so that the temperature of the Freon vapor decreases and condenses from the gaseous liquid to the liquid, then it flows away from the condenser to the evaporator. The evaporator is composed of another serpentine tube, which is in contact with the refrigerator. This serpentine tube is thinner than the serpentine tube of the condenser, so the flow rate of Freon is quickened, followed by a sudden drop in pressure. This is consistent with the so called Bernoulli principle.

As the pressure drops sharply in the evaporator, freon evaporates vigorously and changes from liquid to gaseous state, which is accompanied by a reduction in temperature. As the heat is always transferred from the hotter object to the colder object, the hotter food in the refrigerator transfers heat to the serpentine tube which runs on the freon gas, so as to achieve the purpose of refrigeration.

After the above process is completed, the refrigerant freon gas is ready to be re absorbed by the compressor, thus starting the next cycle.

Because Freon will destroy the ozone layer, it has been phased out and switched to other refrigerants, but they have the same refrigeration principle.

There are two main types of refrigerators. One is a vertical refrigerator like a household refrigerator, the other is a refrigerator refrigerator commonly used by a store. The cabinet refrigerator is not very convenient to use, but it is more efficient than the previous one. In fact, every time the door of a household refrigerator is opened, a large amount of cold air will flow downward and be replaced by hot air because of the cold air ratio. But this phenomenon will not happen on the cabinet refrigerator, and the advantage of the cabinet refrigerator is that it has very little need for defrosting.

The above is a schematic diagram of the refrigerating process of the refrigerator.

The refrigerant from the compression is in the high-pressure gas state. When it enters the condenser, it releases heat, and becomes liquid and enters the storage. The refrigerant then flows into a thinner tube and the pressure drops. This low pressure liquid becomes cold, and when it enters the serpentine tube that is in contact with the air around the food, the refrigerant becomes a gas again and absorbs the heat of the food. After absorbing the heat, the refrigerant enters the compressor and starts the next cycle.

Continue to cool in "magnetic cup"

However, the laser method can only cool the atoms up to about 1/1000000 at most, far less than the temperature required by Bose Einstein condensation. The second step is to continue to cool the atoms by evaporative cooling.

To understand this method, let's first observe how a glass of hot water gets cold. Hot water in a teacup is made up of many water molecules. The energy of these water molecules is large and small. Because the energy of the water molecules moves fast, they quickly run out of the cup and turn water vapor into the air. In this way, as the energy of the water molecules gradually run away, the temperature of the water will gradually become colder. If we also have an atom cup to hold the atoms in, then if there is enough time, the atoms in the cup will cool to enough low temperature.For Bose Einstein condensation, the cup we use is made of magnetic field. The atoms are placed in this "magnetic cup" for evaporative cooling, which is called magnetic trapping trap.

We know that the atom itself is magnetic, like a small magnetic needle. We can design a very strong magnetic field, imprisoning atoms like a well and isolating it from the outside world. In this way, the atoms with high energy will gradually escape from the well edge and the atoms will gradually cool down. Of course, this process is very slow. If we reduce the height of the well, the cooling rate will accelerate.

In fact, in the Bose Einstein condensation experiment, it is through increasing the height of the well gradually to accelerate the cooling rate. Of course, this speed must be well controlled. Because the speed is too fast, the atoms that finally reach Bose Einstein condensates will be too few. By carefully controlling the velocity, most of the atoms can reach the Bose Einstein condensate in a relatively short time.

Through these clever masters, physicists finally realized their dreams for decades. In 1995, Connell and Weinman first made about 2000 rubidium atoms at the temperature of 0 00002k to achieve Bose Einstein condensation. Subsequently, he used sodium atoms to do the same experiments. The experiments he designed can make more atoms reach Bose Einstein condensates, so we can do more in-depth research on this strange state. He also used two "super atoms" to get very clear interference fringes, just like the interference fringes produced by two laser beams.

Their success has raised the climax of Bose Einstein condensation in the world. Now, around more than 30 laboratories in the world have successfully realized Bose Einstein condensation, and the condensed state of lithium and potassium has recently been obtained. In addition to alkali metals, French scientists first made the Bose Einstein condensate of helium atoms not long ago. Progress in experimental technology has also been very rapid. Scientists have recently developed a very small chip that allows atoms to reach Bose Einstein condensate in a very short time. This achievement will enable more laboratories to join the research in this field.

Microwave, versatile in the age of high technology

Microwave is an electromagnetic wave with wavelengths ranging from 1 millimeters to 1 meters, with frequencies ranging from 300 MHz to 300000 MHz. It is a member of the family of electromagnetic waves, radio waves, infrared rays, visible light, ultraviolet rays, X rays and so on.

With the development of modern science and technology, the application field of microwave is not only familiar with microwave communication, but also involves medical and health, road construction, aerospace, environmental protection, energy transmission and other aspects, as well as people's lives.

Canadian scientists discovered that microwave can increase the speed of chemical reaction between some organic compounds by more than 1200 times, so that people have a new understanding of microwave, greatly changing the prejudice that microwave can only heat water substances, and expand the function of microwave heating to the field of organic matter, and have made one new achievement after another.

According to reports, Japanese scientific research institutions have developed new microwave technology for firing ceramics, which can shorten the firing time and reduce energy consumption.The new technology is characterized by letting the blank absorb microwaves, and then firing the ceramic products from the heat emitted by itself. The special furnace with this method has been developed successfully, and the furnace wall has a double-layer structure, which is composed of microwave absorbing ceramics and insulation materials. Compared with the existing burning method, the internal heating method can make the ceramic temperature rise uniformly during the firing process, thereby reducing the phenomenon of deformation and uneven color and reducing carbon dioxide emissions. The quality of ceramic products fired by microwave is not inferior to that produced by electricity, gas or heavy oil. This technology can be used to produce insulating porcelain bottles and industrial ceramics used in semiconductors, automobiles and other fields.

Researchers at the Harvey laboratory in the United States have developed a new method of using microwave to dismantle the concrete buildings of atomic reactors. Because the work of an atomic reactor brings different levels of radioactivity to its surroundings, it is not allowed to raise a bit of dust in the demolition of buildings. Using microwave to heat the moisture contained in concrete, the volume of water will expand during the process of turning into water vapor, so that the concrete will burst. During this process, no dust will be generated, thus ensuring that the environment is free from contamination.

In highway construction, people often feel time-consuming and laborious for melting bitumen, resulting in heavy smoke to pollute the environment. In the course of transportation, they should also keep warm so as not to cause solidification. If microwave heating is used to heat the asphalt, satisfactory results will be achieved. The United States also invented a way of repairing roads by microwaves. The methods used in the past often make the pavement cool and difficult to combine with the newly added asphalt, and the repaired road also loses its original leveling. After microwave repair, a device is used to send microwave to the road surface to repair. It can quickly heat the road surface and melt the asphalt. Therefore, the new asphalt and the asphalt on the road surface will be melted together, and then the roller will be used to flatten the road surface easily.

Microwave can effectively transmit energy: not only can the ground electronic facilities provide energy by microwave irradiation, but also the aircraft in the air can receive energy by receiving microwave beams from the ground and make scheduled flight plans. The microwave station on the ground will transmit the microwave with high energy to a very large space. The instrument installed on the aircraft can receive microwave energy and transform the energy into electric energy, driving the engine on the airplane. According to this principle, people only need to set up a microwave transmission station every one hundred or two hundred kilometers on the ground, so that they can make the microwave aircraft fly around the earth without landing or refueling.

In September 1987, the first unmanned microwave aircraft successfully flew to the blue sky at the airport outside nirtaihua, Canada. It lasted 20 minutes at high altitude. Its energy comes from the disc antenna installed under the plane. The transmitter on the ground converts electricity into microwaves to transmit to the sky. After receiving the aircraft, it will be converted into electricity and propellers to fly.

Shortly afterwards, the United States developed an unmanned aerial microwave surveillance aircraft. The flight device is powered by a 2 MW microwave launched from the ground microwave launch station. When the receiver on the aircraft converts the received microwave into electrical energy, it can supply the motor to use. The flying height of the aircraft can reach 183-21350 meters, and it can stay in the air for 90 minutes.

In 1991, scientists from the United States and Canada jointly established an advanced microwave station on the ground. Here is the largest microwave transmitting antenna in the world, which can transmit microwaves to tens of thousands of meters in height. During the flight, the energy supplied by the microwave can be continuously flying for 3 months at a height of 20000 meters above the ground.
Now, Japan is also ahead of the research and development of microwave airplanes, and has developed a more advanced microwave powered aircraft. By adopting the latest semiconductor technology and automatic orientation technology of phased array antenna, the microwave can be transmitted farther and the directional accuracy is higher. At the same time, the mechanical transmission of the transmitting antenna is avoided, and the control is very flexible, which is especially suitable for microwave transmission on the satellite.

In the development of space industry, people are envisaging the use of microwave energy to launch the space shuttle, so that the funds needed are only 1/20 of the total cost of launching rockets. At the same time, scientists used microwave for atmospheric detection and monitoring, creating a good air environment for the smooth flight of rockets and satellites.

Microwave in modern medicine can be used to treat various diseases, relieve pain and mental burden for patients. An extremely small microwave generator can be directly transported from the mouth, urethra, and anus into the human body, directly killing cancer cells. It can be used to treat cancer or abscess in the stomach, esophagus, prostate, etc. If the tiny microwave coil is sent directly to the blood vessel, the excess material of the vascular wall can be removed and the inner wall of the blood vessel becomes smooth and elastic.

American medical scientists have found a new way to shrink swollen tonsils by using microwave technology, so that patients can avoid the discomfort and bleeding caused by traditional tonsillectomy. During the treatment, the medical staff inserted a needle size heating probe into 3 points of two swollen tonsils and stayed at each point for a few seconds. The temperature of these heating probes is between 120 degrees Celsius and 150 degrees Celsius, which makes the swollen tonsils atrophy rapidly.

Some medical experts in Japan apply microwave coagulation to the treatment of gastric cancer. It uses microwave to coagulate the protein and then coagulate and necrosis the tumor cells. The current microwave coagulation therapy is guided by ultrasound. The needle electrode is inserted directly into the tumor tissue from the skin directly through the skin, and the tumor tissue is coagulated by the microwave of the electrode to kill the tumor cells. This method does not require open surgery. It has less damage to patients and lower treatment cost. It is welcomed by doctors and patients.

In the modern war, a powerful microwave weapon is entering the application stage. It has no trace, no sound, but can attack various targets, including missiles, aircraft, tanks, warships, radar, computers, photoelectric components and so on, resulting in great destructive force and destructive power.

Microwave weapons use microwave energy to generate high temperature, ionization, radiation, sound wave and other comprehensive effects, and transmit them in a certain direction in the form of "bundles" to destroy or damage targets. It has been measured that the use of microwave energy radiation per square centimeter of 0.01 watts can directly invalidate or burn out components such as communications, radar, navigation, and other electronic systems. When the microwave radiation at 80 watts per square centimeter is used for 1 seconds, the organs in humans and animals will lose balance due to high heat, and the coordination of functions will be in disorder, which will soon affect the nerve center and heart and lead to death.

The composition of microwave weapons is generally composed of three parts: ultra high power microwave transmitter, large high gain antenna and tracking and aiming control system. When attacking the target, the large antenna first aggregates the microwave output from the ultra high power transmitter in the narrow beam, forming a strong beam energy, and then shoots at the target at a speed of 300 thousand kilometers per second. Comparing with its working principle and structure, microwave weapons are thousands of times higher than that of their similar radars in terms of energy radiation. In the same weapons that emit particle beams, the microwave weapons are much larger than the laser weapons in the width of the beam, and the attenuation is slow.

The most important function of microwave weapons in application is to deal with electronic devices. Electronic equipment in modern warfare is a necessary guidance system for all kinds of weapons in search of targets and attacks. It has a very strange function. It is difficult to take other weapons to deal with it. The microwave weapon is not the same. Because it is a kind of electromagnetic wave emitted by itself, it is very easy to disturb and destroy the electronic oscillation, and it can cause the whole electronic work system to be paralyzed, thus making the weapon system lose the ability to attack and defend. With the development of science and technology, various stealth weapons have appeared one after another. These new weapons can effectively avoid the detection and tracking of sensors such as radar and infrared. However, these stealthy weapons will suffer from the high energy beam of microwave weapons. The "invisibility cloak" applied to these weapons is a special coating that will be destroyed in a short time and can be melted instantly. Such a result will destroy the entire stealth weapon. Thus, from the date of birth, microwave weapons are destined to be the nemesis of stealth weapons.

Application of high speed photography in practice

If the world is a plate

Panoramic photos refer to images that are photographed at 360 degrees. The camera rotates along a fixed axis. So that it can take all the field shadows. The camera rotates at the same speed. The ideal is to take outdoor scenery (the right picture is seen from below) Eiffel Tower. When shooting a closed environment (upper left and upper left), the use of panoramic rotation will produce different party building effects. This is like a label removed from a bottle: the previous image is curved, and only part of it can be seen: using full photography, the label becomes a "plane" map, and every corner of it is taken in view. The picture below is a photograph taken by stroboscopic photography, and the "dancer" on the left is taken by "slit scanning" photography.

First of all, shooting stroboscopic photos can be used in experimental teaching: observe the movement rules of a sphere in reality, and understand the motion law of human body in depth. Or applied to the study of machine vibration: eliminating vibration is very important for prolonging the life of machine or eliminating noise caused by vibration.