China's Sky Eye: Exploring the Mysteries of the Universe

The China Sky Eye (FAST) is currently the largest radio telescope in the world. As a major national scientific and technological infrastructure, it is a giant eye for observing the sky and a national treasure, and has achieved a major original breakthrough in my country's cutting-edge scientific field. The China Sky Eye has produced scientific results in multiple research directions, deepening human understanding of the universe. Since its completion and commissioning in September 2016, scientists have discovered more than 660 pulsars through the China Sky Eye, which is more than five times the total number of pulsars discovered by all radio telescopes in the world during the same period. With an annual observation time of more than 5,300 hours, the China Sky Eye, the world's largest and most sensitive radio telescope, has helped scientists achieve a series of research results in the field of astronomy, expanded the human vision of observing the universe, and become a representative project for China's scientific and technological self-reliance.

| China Sky Eye

The Five-hundred-meter Aperture Spherical radio Telescope (FAST), located in Qiannan Buyi and Miao Autonomous Prefecture, Guizhou Province, China, is a major national "Eleventh Five-Year Plan" science and technology infrastructure construction project. China's Sky Eye is built on a spider web with the world's largest span, highest precision, and very special structure and working method. With the help of 50 steel columns, 670 steel cables and 2,225 pull-down cables, this large spider web covered with 4,450 reflectors will deform due to the tension applied by the tractor. If it works together with the receiver on the top, China's Sky Eye can effectively observe electromagnetic wave signals in different areas of space. This is why China's Sky Eye's observation sensitivity and data reception capabilities are more powerful than similar products in other countries.

| Technological innovation of China's Sky Eye

1. A new system for the ultra-large radio telescope, namely the active reflector and feed support systems, was created, which achieved active displacement of the 500-meter aperture reflector and high-precision positioning of the feed cabin, a major breakthrough in radio telescope construction technology.

2. A ring beam support form that is suitable for complex mountainous terrain was proposed, a target configuration initial strain compensation method for cable net morphology analysis was invented, the fatigue performance of actively shifted cable nets was studied, and innovative structural designs such as large scale, ultra-high precision and active shifting were achieved.

3. We developed structural steel cables with an ultra-high stress amplitude of 500 MPa and millimeter-level precision, and invented a variety of large-span, high-precision construction methods, breaking through the extremely harsh and complex site restrictions on site and completing the construction of the main structure of the telescope with a very large span and extremely high precision.

4. A large-scale, high-precision, high-dynamic measurement control and safety assessment technology was invented, which enables the provision of high-precision position information of the reflecting surface and all-weather, high-precision, large-scale, high-sampling rate feed support dynamic measurement.

5. In terms of management innovation, a full-process engineering consulting model was adopted, creating a "cross-shaped" cross-management system and a "five-dimensional" project management method, achieving the organic integration of energy-saving, green, and environmental protection management systems, and opening up a new model for large-scale scientific engineering construction management.

| Outstanding Contributions of China's Sky Eye

Since its completion, China's Sky Eye has continued to produce results in the fields of the origin and physical mechanism of fast radio bursts, neutral hydrogen universe research, pulsar search and physical research, pulsar timing and low-frequency gravitational wave detection. The recent discovery of the largest atomic gas structure in the universe was made by Chinese scientists through the China Sky Eye, and the relevant results have been published in the academic journal Nature. China's Sky Eye can detect the faint radiation emitted by extremely thin diffuse atomic gases far away from the center of galaxies, which opens a new window for studying the origin of celestial bodies in the universe.

Observing the gas in the universe is a very important research topic in the field of astrophysics, and the origin of all celestial bodies in the universe is inseparable from atomic gas. It is reported that the main evolution process of galaxies is to continuously absorb atomic gas from the universe and then transform it into stars.

This discovery poses a challenge to the study of the evolution of galaxies and their gases in the universe. Existing theories have difficulty explaining why these rarefied atomic gases have not been ionized by the ultraviolet background radiation in space for such a long time. This observation indicates that there may be large-scale low-density atomic gas structures in the universe.

| China's strength in cutting-edge fields

Among the many scientific achievements produced by China's Sky Eye, fast radio bursts are one of the latest and hottest areas. In the vast universe, short and violent radio wave bursts often occur, which usually last only a few milliseconds, but can release huge energy equivalent to the electricity generated on Earth for tens of billions of years. In 2007, astronomers first discovered such millisecond radio waves - fast radio bursts. So far, astronomers have observed hundreds of fast radio bursts and inferred their evolutionary stage by the complexity of the surrounding environment.

At present, scientists are still unclear about the physical origin, surrounding environment, and central mechanism of fast radio bursts, and there is a lack of direct observation data on the physical parameters of their core areas. Recently, Chinese scientists used the China Sky Eye to conduct in-depth observations of a fast radio burst located outside the Milky Way, and for the first time detected the magnetic field changes in the surrounding environment only 1 astronomical unit (that is, the distance from the sun to the earth) from the center of the fast radio burst. In this study, the research team conducted long-term monitoring of the fast radio burst FRB20201124A located outside the Milky Way, and observed 1,863 burst pulse signals in 54 days and 82 hours. Based on this largest fast radio burst polarization observation sample to date, several important discoveries were made. The team is conducting further research and hopes to find direct observational evidence that determines the core physical processes and energy mechanisms of fast radio bursts, and to reveal the physical origin of this mysterious cosmic phenomenon as soon as possible.

| Application Value

1. Promote independent industries

The construction of the 500-meter Aperture Spherical Radio Telescope involves many high-tech fields, such as antenna manufacturing, high-precision positioning and measurement, high-quality radio receivers, sensor networks and intelligent information processing, ultra-wideband information transmission, large-scale data storage and processing, etc. The key technical achievements of FAST can be applied to many related fields, such as large-scale structural engineering, kilometer-wide high-precision dynamic measurement, large-scale industrial robot development, and multi-beam radar devices. The construction experience of the 500-meter Aperture Spherical Radio Telescope will have an impact on the development of China's manufacturing technology towards informatization, extremeization and greening.

2. Contribute to national security

Extend China's space tracking and control capabilities from the geosynchronous orbit to the outer edge of the solar system, increase the downlink rate of deep space communication data by dozens of times, become the most accurate pulsar timing array in the world, and produce pulsar clocks for the forward-looking research of autonomous navigation. Conduct high-resolution microwave patrols, diagnose and identify weak space signals with a resolution of 1 Hz, and serve national security as a passive strategic radar. It can be used as the incoherent scattering radar receiving system of the "Meridian Project", providing high resolution and observation efficiency; track and detect coronal mass ejection events, and serve space weather forecasts.

3. Explore the Universe

As a multidisciplinary basic research platform, China's Sky Eye has the ability to extend neutral hydrogen observations to the edge of the universe, observe dark matter and dark energy, and search for the first generation of celestial bodies. It can study the structure of matter and physical laws under extreme conditions; it is expected to discover strange stars and quark star matter; it can discover neutron star-black hole binaries, and accurately determine the mass of black holes without relying on models; it can detect gravitational waves by accurately determining the arrival time of pulsars; it can be used to search and identify possible interstellar communication signals, search for extraterrestrial civilizations, etc.

(Pictures from the Internet)

Author | Gu Junzhe has a master's degree in computer science and technology. After graduation, he has been engaged in the collection and organization of online information, paying attention to popular science knowledge and exploring cutting-edge technology.