China’s “Sky Eye” is open to the world. Can scientists find alien civilizations?
The earth is the cradle of mankind, but mankind cannot live in the cradle forever. —— Konstantin Tsiolkovsky (Soviet scientist, founder of modern astronautics and rocket theory, father of astronautics)
In Guizhou, China, a huge "sky eye" is lying quietly in a karst crater in the Buyi and Miao Autonomous Prefecture in southern Qiannan, looking at the universe curiously.
▲ The "Sky Eye" of the 500-meter spherical radio telescope in China. Picture from: Xinhuanet
It is a four-year-old doll, but it has a powerful "body" consisting of an active reflector system, a feed support system, a measurement and control system, a receiver and terminal, and an observation base. It is a 500-meter A spherical radio telescope with an area equivalent to 30 standard football fields.
Its father is the Chinese astronomer Nan Rendong. In 1994, Mr. Nan Rendong put forward a construction idea. After 22 years, "Sky Eye" was put into use on September 25, 2016. It is the world's largest single-caliber radio telescope with my country's independent intellectual property rights.
A few days ago, China announced to the world that the "Sky Eye" will be officially opened to the global scientific community on April 1, 2021, to provide contributions and development experience for the community with a shared future for mankind .
What can this eye see?
Eyes, of course, are used to see "light".
Humans can see things because electromagnetic waves enter our eyes, and visible light is a very small part of electromagnetic waves.
At the same time, there are still many bands of electromagnetic waves that are invisible to the naked eye. These electromagnetic waves carry a lot of information, including a large number of extremely important astronomical research objects, such as radio galaxies, quasars, pulsars, and cosmic microwave background radiation. This requires the use of radio telescopes such as "Sky Eye" to receive and analyze these signals.
▲ Visible light occupies only a small part of electromagnetic waves. Image from: Wikipedia
"Sky Eye" engineering chief engineer and chief scientist Nan Rendong introduced that with "Sky Eye", humans can do many things:
- It can extend the observation of neutral hydrogen to the edge of the universe, observe dark matter and dark energy, and search for the first generation of celestial bodies
- It takes one year to discover about 7,000 pulsars and study the structure and physical laws of matter under extreme conditions
- Hope to discover strange and quark star matter
- Discovery of neutron stars-black hole binary stars, without relying on models to accurately determine the mass of black holes
- Detect gravitational waves by accurately determining the arrival time of pulsars
- Joined the International Very Long Baseline Network as the largest station to image the hyperfine structures of celestial bodies
- It is possible to discover the giant maser galaxy with high redshift, realizing the first observational breakthrough of methanol super maser outside the Milky Way
- Used for searching and identifying possible interstellar communication signals, looking for extraterrestrial civilization
Open your eyes to see the universe, what are the results?
Before announcing its opening to scientists around the world, "Sky Eye" has been in operation for several years, with fruitful results.
In October 2017, "Sky Eye" discovered 2 new pulsars. One pulsar is 16,000 light-years away from the Earth and has a rotation period of 1.83 seconds. It was named J1859-01. The other one is about 4,100 light-years away from the earth and has a rotation period of 0.50 seconds. It is named J1931-01.
In December 2017, "Sky Eye" again discovered 3 pulsars. So far, "Sky Eye" has discovered more than 240 pulsars. The number of pulsars discovered by "Sky Eye" in just two years exceeded the sum of the number of pulsars discovered by multiple pulsar search teams in Europe and the United States during the same period.
▲ Hypothetical picture of pulsars. Picture from: Astronomy Online
In 2020, 4 papers were simultaneously published in the well-known academic journal "Nature", discovering and demonstrating that a Hanoi fast radio burst FRB 200428 originated from the magnetar SGR 1935+2154, which is the theory that "fast radio bursts originate from a magnetar" Conjecture adds strong evidence. One of the papers is based on the observation results of "Sky Eye".
What is the meaning of the sky's eye?
In April 2020, the "Sky Eye" Observation Time Allocation Committee began to solicit free application projects from the domestic astronomical community. More than 170 applications have been received in more than half a year. The total application time is about 5,500 hours. Actually approved 1,500 aircraft hours, only 30 % Can get support and competition is fierce.
In January 2021, after China announced the opening of "Sky Eye" to scientists around the world, it caused heated discussions in the scientific community. Scientific research teams and scientists in many countries immediately issued applications, but in the end China could only try to spare about 10% of the observation time. Used for sharing.
This shows how important the "eye of the sky" is. And the reason why it contains such a high gold content is because its observational data is the basis for human beings to go deeper into space.
1. Drawing an accurate "map" of the universe
Careful, you should have discovered that the keyword pulsar has appeared many times. Before talking about it, let's talk about sailing first.
If you are driving a boat on the vast ocean without a map, compass, or positioning system, you can only get to your destination by luck.
But if you have a positioning system, everything becomes extraordinarily easy. You know what the route is like, where you are currently, where you want to sail next and so on.
Imagine if you were driving a constant star spacecraft and set off from the solar system to another star system 4 light-years away, how could you locate it?
There is no way to pinpoint it.
▲ Unlike plane navigation, space navigation has no east, west, north, up and down distinctions. Picture from: Guillermo Ferla (Unsplash)
The sun is just a star among the billions of stars in the universe that can no longer be ordinary. There is only one consequence of positioning by the sun alone, and you will be lost in the universe forever.
The pulsars that "Sky Eye" focuses on observing and looking for are the best known cosmic-level positioning reference objects.
Just as the earth has a magnetic field, stars also have a magnetic field; just as the earth is rotating, stars are also rotating; and just like the earth, the direction of a star's magnetic field is not necessarily on the same line as the axis of rotation. In this way, every time a star rotates once, its magnetic field will draw a circle in space, and it may sweep the earth once… To send out radio signals like a pulsar, a strong magnetic field is needed. And only the smaller and the heavier the star, the stronger its magnetic field. Neutron stars are such high-density stars. Only high-speed rotating neutron stars can play the role of pulsars.
It takes twenty-four hours for the earth to rotate once, but the pulsar's rotation period can be as small as 0.0014 seconds, so its super-strong magnetic field emits periodic pulse signals, which looks like a high-speed beacon flashing and flashing, because the rotation period is extremely Stable, it has become an ultra-high-precision clock for humans to measure the time and space of the universe.
▲ The pulsar rotates at a high speed, and the super-strong magnetic field emits periodic pulse signals, becoming a "cosmic lighthouse . " Picture from: Wikipedia
▲ X-ray / visible light band composite image of the Crab Nebula pulsar. Image from: Wikipedia
If the spacecraft enters the depths of the universe and telescopes and satellites cannot observe directly, you can rely on pulsars to calculate the position. The more pulsars are detected, the more accurate the positioning will be.
This is one of the great meanings of the "Sky Eye". It is drawing an accurate map of the universe. Although it is only a small beginning, the impact is far-reaching.
2. Explore the origin of the universe
Human beings have been thinking about a question since the enlightenment: where do we come from. "Sky Eye" helps to explore this problem.
"Sky Eye" can patrol the neutral hydrogen in the universe. The energy produced by hydrogen fusion lights up the stars, and the sun emits light and heat, creating the earth, the cradle of human life.
In addition to the formation of stars, a part of the hydrogen in the galaxy will remain in the form of neutral hydrogen atoms, called neutral hydrogen.
▲ A map of neutral hydrogen in the universe drawn by scientists. Picture from: Rose Latoz (SCINEWS )
Through the observation of relatively primitive interstellar gas, it is found that in the Milky Way and many extragalactic galaxies, the isotope deuterium of the light element helium is basically evenly distributed relative to the amount of hydrogen. This is in sharp contrast to the uneven distribution of many heavy elements.
Scientists speculate that the high temperature and high density expected in the first few minutes after the Big Bang can easily lead to the synthesis of light elements, while the heavy elements are synthesized deep in the cores of many stars, and they are not scattered until a supernova occurs. Yes, they will not be evenly distributed relative to the amount of hydrogen.
Zheng Xiaonian, deputy director of the National Astronomical Observatory, pointed out that studying the neutral hydrogen in the universe can "study the large-scale physics of the universe to explore the origin and evolution of the universe."
3. Explore extraterrestrial civilization
In the novel "Three-Body", the three-body man envelops the earth with two-dimensional unfolding protons, forging the scintillation of cosmic background microwave radiation, in order to prove to mankind that there is an extraterrestrial civilization and the level of technology far exceeds that of mankind.
The "Sky Eye" can observe the cosmic microwave background radiation, but the cosmic microwave background radiation is a product of the Big Bang, which is too messy and messy.
According to the Big Bang theory, the original universe was very small, with very high density of matter and energy, and very high temperature. After the Big Bang, even if the space has expanded for a long time, the heat of that year will not be completely dissipated, and there will be residual heat evenly distributed throughout the universe, which is the cosmic microwave background radiation.
▲ A hypothetical picture of the Big Bang. Picture from: Wikipedia
What the "eyes of the sky" has to do is to screen out the strange, irregular, and obviously processed signals that are temporarily inconsistent with scientific understanding from the massive messy cosmic microwave background radiation, and see if these signals come from outside the earth. Civilization is issued to indirectly infer the existence of extraterrestrial civilization.
At the beginning of 2019, the Canadian CHIME telescope team announced the second discovery of a repeated rapid radio burst (FRB). At that time, astronomers pointed out that although the cause of this phenomenon could not be confirmed for the time being, the possibility that this signal was sent by an extraterrestrial civilization could not be ruled out.
The earth is very good, why should we explore the universe?
If mankind decides to go deep into the universe and continue to evolve, it will be as difficult as our ancestors who climbed from the ocean to the land and stepped wrong one step at a time.
But if we do not take this step, mankind will always lose the possibility of further progress, just like our ancestors did.
Since mankind entered a civilized society, resource conflicts have been the root cause of continuous economic crises and wars . Every technological explosion is constantly releasing the potential of resources. However, resources always have the limits of development and utilization, plus the number, lifespan, and Per capita resource consumption is still rising, and crises brought about by resource shortages will only get faster and deeper each time.
▲ Landing in Normandy. Picture from: Wikipedia
Einstein predicted that the weapon of the Fourth World War will be stone, which shows the urgency and importance of alleviating resource conflicts.
At present, it is proved that just a moon on the moon has extremely rich mineral resources and a large amount of helium-3. By using deuterium and helium-3, helium fusion can be carried out as an energy source for nuclear power plants.
Therefore, going deep into the universe is an inevitable choice for mankind. A large amount of resources are waiting for mankind to tap. With the help of the "eyes of heaven," we can lay a good foundation for future generations to go further.
Source of title picture: Xinhuanet
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