China, as one of the great powers, naturally will not let go of the research and exploration of these mysterious substances in space, trying to find some unknown laws about the universe and physics and unlock the unknown veil about the field of human science and technology. To this end, China also built the world's deepest underground laboratory at a depth of 2,400 meters in Jinping Mountain, Xichang Yi Autonomous Prefecture, Sichuan. The research object of this laboratory is dark matter in the endless universe.
So, why do we choose to study dark matter and why do we choose to study dark matter at a depth of 2400 meters underground? What's special about dark matter?
First of all, let's learn about the main research target of this laboratory hidden at a depth of 2400 meters underground-dark matter.
Dark matter is a substance based on the theory of galaxy rotation curve. This theory, like Einstein's gravitational wave, violates Newton's view of gravity and proves that the mass of galaxies is very different from that expected by the theoretical model. These quality differences come from many unobservable substances between galaxies, which are widely and abundantly present in the universe and are an important part of cosmic substances, and can form any known substance at will. Therefore, this mysterious and invisible substance is called dark matter.
Moreover, this dark matter accounts for more than 80% of the total mass of all substances in the universe. On average, trillions of dark matter pass through the human body every day, but the human body will not feel anything. Some widely accepted views believe that the main components of this dark matter are inert particles with weak interaction or very light neutral particles. At present, human understanding of dark matter is still very limited. In human limited cognition, it has been confirmed that dark matter has the following properties:
First of all, dark matter has mass, which is the conclusion that people find that dark matter participates in gravitational interaction. But people can't determine the specific value and size of dark matter mass. Secondly, dark matter does not participate in the interaction between electromagnetic waves and photons, so it is very dark and hardly emits any light.
Moreover, the motion speed of dark matter is much lower than the speed of light, and it is a very cold and dark substance, which makes the structural characteristics of dark matter very stable and will not change much, which is very different from any particle we know at present, and successfully challenges the basic standard model of particle physics.
In the early 1920s, people first put forward the conjecture and theory of dark matter. In the process of observing the motion of galaxies, astronomer Kapteyn first speculated that there might be invisible substances around galaxies according to some abnormal phenomena of galaxy motion, but it was not confirmed.
In the early 1930s, while studying a galaxy cluster near Leo, Zwicky, who is also an astronomer, measured the mass of the galaxy cluster by photometry and dynamics respectively, and found that the difference between the two methods was more than 160 times. The conjecture about dark matter is formally put forward: dark matter has mass, but it does not emit light, so it can be measured by kinetic energy, but not by photometry. This conjecture also made the word dark matter appear in academic papers, but Zwicky did not further study dark matter.
It was not until thirty years later that Rubin, another astrophysicist, became interested in dark matter. After more than ten years of long observation and data calculation, he described and studied dark matter in detail, and indirectly confirmed the existence of dark matter through the "loss" of the mass of the Milky Way.
However, the direct confirmation of the existence of dark matter was officially confirmed at the beginning of this century. In 2006, an astronomical research team observed a series of galaxy collisions in the cluster of galaxies through the X-ray telescope. During this galaxy collision, dark matter was separated, which opened the door for people to formally study dark matter.
However, whether it is direct observation or indirect observation, it only stays in the "observation" stage. The study of dark matter requires practical detection means. These detection methods all need certain detection evidence as a standard to confirm the successful capture of dark matter. At present, the recognized detection evidence is mainly realized by detecting the radiation scale of galaxies and the universe. As far as galaxies are concerned, dark matter can be confirmed by observing the movement of galaxy clusters, X-rays and gravitational lenses. From the cosmic background, dark matter can be calculated by studying the total microwave radiation of the universe and the overall structural scale of the universe.
Of course, as long as dark matter can interact with matter, we can detect it This alone will pose great challenges and difficulties to our human science and technology and detection conditions. At present, there are three main methods: direct detection, indirect detection and collider detection.
Among them, the first two detection methods are indirect or direct detection through the traces left by the interaction between dark matter and other substances. The last detection method of the particle collider is to produce dark matter in the particle collision experiment, but the dark matter particles produced in the particle collision are difficult to detect and the dark matter is still invisible. Therefore, the detection method of particle collision generally combines the first two direct or indirect detection methods to achieve the best effect.
With the gradual popularization of the scientific topic of dark matter, many countries have made arrangements for dark matter experiments, and China is no exception. In 20 10, China's first extremely deep underground laboratory, China Jinping underground laboratory, was officially put into use, with a depth of 2400 meters, ranking among the deepest laboratories in the world, and dark matter detection research was being carried out.
China Jinping Underground Laboratory was rebuilt from a tunnel excavated during the construction of Jinping Hydropower Station. The extremely deep underground position can effectively shield the interference of cosmic rays, making the detection results of dark matter detectors more accurate. In order to make the anti-interference ability more powerful, the dark detector made of high-purity germanium crystal material is wrapped with concrete up to half a meter thick, polyethylene up to one meter thick and a layer of lead, and even neutrons are not allowed to enter.
Moreover, because the construction location of this underground laboratory is convenient, researchers only need to control the detection equipment of the underground laboratory on the ground and study and analyze the detection data. China Jinping Underground Laboratory mainly uses two detection methods to detect dark matter, namely, the low-temperature semiconductor detector represented by Tsinghua Research Group and the liquid xenon detector of Shanghai Jiaotong University.
Both detectors use the recoil nuclear data generated by the collision of dark matter with particles to confirm the existence of dark matter, and use direct observation to study dark matter, which has raised the international direct detection level of dark matter to a new height.
At present, in the process of developing and improving dark matter detectors, China has mastered the commercial manufacturing technology of dark matter detectors, and through the results of precise dark matter detection experiments, the existing area of dark matter given by the American experimental group has been excluded, which has narrowed the existing range of dark matter and provided greater possibilities for the discovery of dark matter.
With the continuous progress of dark matter research, China is not satisfied with just studying dark matter, but will be upgraded to a physics laboratory that can study neutrinos and nuclear celestial bodies. In order to meet the experimental needs, Jinping Underground Laboratory officially started the expansion plan in 20 14, which was even included in the "Thirteenth Five-Year Plan" in the field of national science and technology construction, and will soon be upgraded to an extremely deep underground physics laboratory with extremely low radiation, which can accommodate more experimental projects and teams. Its area will increase from 4,000 cubic meters to 300,000 cubic meters, making it an excellent underground research laboratory.
So, what's the use of dark matter, an extremely mysterious substance in the universe?
In its realization stage, people's understanding of the universe is still very limited. With the confirmation of dark matter, dark energy, gravitational waves and double-slit interference experiments, the traditional physical model seems to be no longer applicable to the current rules of the universe.
The confirmation of dark matter can not only correct and open a new horizon of physical model and astrophysics for us, but also explain some fields and phenomena that cannot be explained by science at present: Is it possible that the dark matter with a high proportion but unknown in the universe is what we are familiar with in TCM and Taoism?
If the development level of human science and technology can use and transform dark matter at will, then maybe human science and technology can take a lot of detours less. We might as well make a bold guess. Since dark matter has the conditions to form all the basic substances in the universe, can we use dark matter to create things, or even "take things from space" to exchange ideas? After all, when electromagnetic wave was just discovered and confirmed, people never thought that it would one day raise the way and method of human information dissemination to a brand-new realm.
Philosophically speaking, the existence of dark matter also affects the supremacy of scientism to some extent. Questioning the widely accepted view that matter determines consciousness may help human beings understand the origin of consciousness and even the essence of the "sixth sense". Then, human science and technology and evolution will reach a new level and dimension.
Therefore, China, a laboratory built 2400 meters underground, will not only study dark matter in the future, but also explore all the unknowns in the universe. Moreover, the exploration of the unknown is also the exploration of science. Only by constantly uncovering the unknown can we surpass ourselves and raise the perfection of cognition to a new height.
These scientific and technological achievements of exploration and development will also help China to have a higher level of science and technology and comprehensive national strength. At the same time, these seemingly mysterious scientific and technological achievements, with the passage of time, will eventually feed back and affect the daily life of thousands of families and bring us a brand-new world.