More than 300 pulsars have been discovered and will be open to scientists around the world on April 1st
China Sky Eye: Seeing the future with the world
More than 300 pulsars!
This is the latest report of the discovery of the "China Sky Eye" 500-meter spherical radio telescope (FAST).
On the morning of February 5th, General Secretary Xi Jinping cordially met with the person in charge of the "China Sky Eye" project and scientific research backbones, and pointed out that the "China Sky Eye" is a major national scientific and technological infrastructure. A major original breakthrough in the field of science, a large number of scientific and technological workers represented by Nan Rendong worked silently and selflessly for this, which is touching.
On April 1st this year, FAST will be officially opened to scientists around the world.
From April 1st to May 15th, solicit observation project suggestions from all over the world, and scientists from various countries can submit observation applications to the National Astronomical Observatory through online methods.
On July 20, the review results were announced, and starting on August 1, FAST observation time was scheduled.
Wu Xiangping, member of the National Committee of the Chinese People's Political Consultative Conference, academician of the Chinese Academy of Sciences, and director of the FAST Science Committee, said in an interview that the "China Sky Eye" is fully open to the world and demonstrates the concept of full cooperation.
"China is ushering in the golden age of radio astronomy development. We must use this precious window period to make major scientific discoveries and contribute to human exploration and understanding of the universe." Wu Xiangping said.
It is expected to make a major breakthrough in Nachtz gravitational waves
The distant starry sky, the vast universe, is full of unknown mystery.
Beyond light years, how is dark matter distributed and how galaxies evolve?
Where did the ten billion-year-old universe come from, and where will it go?
The mystery of the universe attracts human beings to explore continuously.
Going back to the original universe's prospects is precisely to better understand the future direction of the universe, so as to help mankind find a better future.
Take a pulsar as an example, its density per cubic centimeter is equivalent to the mass of a 10,000-ton giant ship compressed.
It was an unimaginable world similar to the "water droplets" in the science fiction novel "Three-Body".
The millisecond pulsars with stable pulse signals are selected from the pulsars, which are expected to be used in interstellar navigation in the future.
Exploring "extraterrestrial civilization" and searching for interstellar communication signals has always been an infinitely tempting scientific goal.
In 1967, mankind discovered the first pulsar.
China rushed to catch up, and it was only 50 years later that it discovered the first new pulsar with its own radio telescope, FAST.
Even though he started late, he had a powerful weapon in his hands and came from behind.
The 500-meter caliber, the world's largest single-aperture radio telescope; the highest sensitivity, ranking first in the world of radio telescopes, and the volume of space that can be effectively explored far exceeds that of the most advanced radio telescopes before.
With many of the world's best FASTs, from the construction concept proposed in 1994, to the completion and commissioning in 2016, to the completion of commissioning, smooth operation and a series of scientific achievements, it has been attracting attention and has received eager attention from the global scientific community.
The journal "Science" has repeatedly reported the progress of FAST, and the journal "Nature" listed the completion of FAST as a scientific event with major global impact in 2016.
It can pierce the "beyond light years" and refresh the sky map of the deep space of the universe; it can patrol the "traces" of the big bang and gain insight into the "previous lives" of the universe... The establishment and operation of the "Chinese Eye" not only opened up the Chinese The new journey of "seeing the universe" has also made mankind's insight into the unknown regions of the universe deeper and broader.
Compared with the "Phoenix" program of the United States, the "China Sky Eye" can expand the patrol target of quasi-solar stars at least 5 times.
Li Wei, a researcher at the National Astronomical Observatory of the Chinese Academy of Sciences and chief scientist of the "China Sky Eye", once introduced that the "Sky Eye" has super "discovery power" in many fields: the number of gas galaxies discovered is expected to increase by 10 times over the past, and the number of pulsars discovered is expected to double Times, it is expected to discover new interstellar molecules...This makes it possible to verify many scientific laws. It has the potential for breakthroughs in gravitational theory, the evolution of galaxies, the origin of stars, planets, and even matter and life.
From October 2017, when two new pulsars were discovered for the first time, to the completion of the trial operation, the discovery of 102 pulsars was announced, to the breakthrough of 300 pulsars...FAST, known as the "China Sky Eye", has made rapid progress in detection results. .
The number of pulsars discovered by it far exceeds the sum of the number of pulsar search teams discovered in Europe and the United States during the same period.
As of the first anniversary of FAST's official operation, more than 40 high-level papers have been published based on FAST data, and the results of rapid radio bursts have been selected as the top ten scientific discoveries published by the journal Nature in 2020.
At present, the "China Sky Eye" has discovered a batch of pulsars in the Milky Way with a diameter of about 100,000 light-years, and has detected fast radio bursts and neutral hydrogen emission lines in distant galaxies outside the galactic.
Wu Xiangping introduced that FAST's comprehensive performance is the world's leading, which greatly expands the limit of human observation of the universe. It can reproduce images of the universe in different periods, detect pulsars with the weakest signal, and continuously expand the number of observation samples.
It is expected that this number will reach 1,000 in the next 5 years, and even the first pulsar outside the Milky Way can be found.
Wu Xiangping said: "FAST pulsars are more than 4 times ahead of the international level in timing accuracy, and are expected to make a major breakthrough in the detection of nanohertz gravitational waves, a cutting-edge scientific detection that has attracted worldwide attention.
Possess China's independent intellectual property rights and owns many of the best
As the world's largest single-aperture radio telescope, how big is the "Chinese Sky Eye"?
Its caliber, that is, the diameter of its active reflecting surface is 500 meters, and its total area of reflecting surface is 250,000 square meters, which is equivalent to the size of 30 standard football fields.
More than 10,000 tons of steel were used to construct its ring beams, cable nets, and 6 high towers supporting the feed cabin.
Although the reflective panel is only 1 mm thick, it also uses more than 2,000 tons of aluminum alloy.
The "China Sky Eye" is very good. It is widely known not only for its "largest" and "most sensitive", but also that it has Chinese intellectual property rights and has three independent innovations: The first is to use Guizhou's natural karst giant depression as a platform. , The second is to independently invent the active deformable reflecting surface, and the third is to independently propose a light cable-drag feed platform and a parallel robot.
It is affectionately nicknamed "Cauldron" and is built in a natural karst crater-Dawotai.
How difficult is it to build here?
At a depth of more than 50 meters below Dawotai, there is the largest underground river in Guizhou—the karst underground rivers of large and small wells. The rainwater basically flows from the underground rivers.
In the event of extreme rainstorms, the water level of the underground river rises and the "cauldron" will be in danger.
Engineers and technicians excavated a flood discharge tunnel along the bottom of the depression, which fundamentally eliminated the risk of flooding.
Whether the feed platform can withstand the test directly affects whether the radio telescope is as stable as Mount Tai.
The feed platform of the American Arecibo telescope weighs 1,000 tons. After years of wind and sun, the supporting steel cables failed to hold the aging, and a fracture occurred in December 2020, causing the platform to collapse.
The "China Sky Eye" adopts a light cable-supported feed platform solution, and a feed cabin controlled by 6 steel cables weighs only 30 tons.
Through the secondary adjustment of the parallel robot, it can achieve millimeter-level high-precision positioning while reducing construction costs and improving safety.
The "Sky Eye" is extraordinary and embodies the wisdom and sweat of the Chinese people.
FAST created a new model for building giant telescopes, breaking the 100-meter engineering limit of traditional telescopes.
During the development and construction period, a large number of ultra-standard design and technical difficulties were overcome, and a number of technologies derived from FAST were identified as the international leading level.
For example, for ultra-low loss and fatigue-resistant dynamic optical cables, a single optical cable can be bent more than 100,000 times.
The steel cable structure with ultra-high fatigue resistance has a fatigue strength of 500 MPa under the condition of 2 million cycles of loading, which is 2.5 times that of the current relevant standards and regulations, and there is no precedent in the international scope.
This is the cable-net structure with the largest span and the highest precision in the world, and it is also the first cable-net system in the world that adopts a displacement working method.
The development and construction of FAST embodies China's independent innovation capabilities and realizes the leap from tracking and imitation to integrated innovation in China's large-scale scientific projects, and creates good opportunities for China's radio astronomy research fields and natural science related fields to provide major discoveries.
Many astronomers pointed out that in addition to astronomical observations and technological innovations driven by the construction of telescopes, the "China Sky Eye" will also become the most accurate experimental platform for verification of physical laws.
FAST's new structure and demanding technical requirements have also promoted technological progress and industrial upgrading in many high-tech fields in China, and at the same time promoted economic prosperity and social progress in the west.
Guizhou, where FAST is located, was once an "economic depression" and a "main battlefield for poverty alleviation."
Today, in the new wave of technological revolution and industrial transformation, the innovation potential of big data and other "curving overtaking" industries has been discovered.
The astronomical town built on the basis of China's Tianyan Science Popularization Base will usher in the establishment of a data processing center covering the entire life cycle of "China's Tianyan".
In order to make the "eyes of the sky" more "brighter", innovation and struggle will never stop
Behind major innovations and breakthroughs, the FAST team is inseparable from the obscure hard work.
In the early 1990s, the idea of building FAST had just sprouted.
At that time, China's largest radio telescope had an aperture of less than 30 meters, while the American Arecibo radio telescope with an aperture of more than 300 meters had been built for 30 years.
The gap is too big.
It is conceivable how difficult it is to develop by leaps and bounds, to be more advanced than the world, and to ask all mankind about the ancient mysteries of the universe.
"A little faster and faster", to let the Chinese use the weapon of exploring the universe as soon as possible is the greatest wish of "Father of Heaven" Nan Rendong during his lifetime, and it is also the mission of the entire FAST team.
With this mountainous responsibility, a large number of scientific and technological workers represented by Nan Rendong have taken root in the remote Guizhou mountains for more than 20 years, overcoming difficulties time and time again, using practical actions to interpret the "catch-up" , Leading, Leaping over" FAST spirit.
I insist that Qingshan does not relax.
In the case of weak foundation and large gap, if a telescope with a diameter of 500 meters is to be built, the total area of its reflecting surface will reach 250,000 square meters. There can be no electromagnetic signal interference nearby, and optical site selection is a big problem.
Since 1994, Nan Rendong, then deputy director of the Beijing Astronomical Observatory of the Chinese Academy of Sciences, repeatedly selected hundreds of satellite remote sensing images, stepped on points one by one in the mountains, and found the closest round crater among many karst landforms.
In 2006, Nan Rendong finally found a home for FAST by taking advantage of the natural trend of Qiannan, Guizhou.
If you don't break Loulan, you won't return it.
In 2007, FAST was approved by the National Development and Reform Commission as a major scientific device during the "Eleventh Five-Year Plan" period, and the construction task is on the right track.
The difficulty of the challenge has also escalated: the telescope is fixed by 6 giant support towers; in order to receive radio wave signals from celestial bodies, the adjustable reflecting surface needs to be supported by a cable net of the same diameter; the feed cabin for receiving electromagnetic waves has a movement range of more than 200 Meters, the accuracy of motion must be controlled at the millimeter level...Engineering tasks integrate astronomy, machinery, materials, radio and other fields, and each craft can be described as unprecedented.
The famous astronomer Nan Rendong, like an "old worker", led the entire team to disassemble the entire large project into many small projects.
From subsystems to parts and components are refined layer by layer, and then time, manpower, and funds are put into this framework, and time nodes are set for each small project...
Little by little, with enthusiasm, relying on independent innovation, one difficulty was overcome and one difficulty was overcome.
Watching the countdown and catching up on progress has become a compulsory course for the team.
In this way, on September 25, 2016, FAST ushered in the overall completion.
From site selection to completion, Nan Rendong gave FAST the last 20 years of his life, creating a miracle.
Tread the bumps into the avenue.
A radio telescope with a single aperture of 500 meters will be the largest in the world as long as it is built.
The FAST team is not satisfied with this.
They want to build the world's best, and they need to build it well so that this "eye of the sky" can see clearly.
For example, in order to make the telescope more sensitive, team members must make the parabola of the reflector more perfect and the receiver closer to the focus.
But such requirements are almost harsh.
The FAST site has a height difference of 150 meters and a 25 mPa change in air pressure, which may cause an error of several millimeters. If the total station measuring the reflecting surface wants to ensure absolute accuracy, it must also consider the errors caused by the curvature of the earth and the included angle... Accurate, the FAST team developed a new set of measurement technology within 6 months, and the measurement accuracy of the reflective surface can reach within 1 mm.
Since the start of construction in 2011, the FAST team members who have shouldered the heavy responsibility of on-site construction have embarked on a dedication journey of persevering day and night and striving for their families.
After unremitting efforts, the team quickly realized the system integration of the telescope, completed the functional debugging task ahead of time, and completed the acceptance of each professional group within two years.
National May Fourth Red Flag League Branch, China Youth Science and Technology Award, China Youth May Fourth Medal Collective; Special Prize of Science and Technology of China Steel Structure Association, First Prize of China Machinery Industry Science and Technology Award, First Prize of Science and Technology Progress of China Electronics Association, Outstanding of Chinese Academy of Sciences Science and Technology Achievement Award... This young team has countless honors and abundant authorized patents and paper achievements, but it is consistent, not forgetting its original intention, and guarding the "eyes of the sky" in a low-key manner.
In order to make the "eyes of the sky" more "brighter", this year's Spring Festival, they are still sticking to their posts.
Now, in order to welcome the official opening to the world on April 1, they are working harder to improve the performance of the telescope, expand the function of the telescope, and ensure stable operation.
(Wei Yang)