The first time humans “seen” black holes is a bit like a donut

The first black hole photo in human history is available! At 9 o’clock in the evening of April 10th, Beijing time, including China, many astronomers around the world simultaneously announced the first black hole. This visual evidence, which was captured by more than 200 researchers over eight years and from eight observation points on four continents, is expected to confirm that Einstein’s general theory of relativity is still true under extreme conditions.

This is the first time humans have stared at a celestial body that once existed only in theory—a black hole with a small body and a very large mass. It is like a “swallowing mouth” of the universe, and even light cannot escape.

The black hole that reveals the truth looks like sweet all

The black hole that reveals the truth is located in the center of a giant elliptical galaxy M87 in Virgo, 55 million light-years from Earth, and the mass is about 6.5 billion times that of the sun. The photo shows a bright ring-shaped structure with a black center that looks a bit like a donut. Its core area has a shadow surrounded by a crescent moon.

More than a hundred years ago, Einstein’s general theory of relativity took the lead in prophesying black holes and has since become a source of inspiration for many science fiction films. Scientists have successively confirmed the existence of black holes through some indirect evidence, but humans have never really “seen” black holes.

“This is the first direct visual evidence that humans have obtained about black holes, confirming that Einstein’s general theory of relativity is still established under extreme conditions,” said Shen Zhiqiang, a Chinese scientist who participated in international cooperation and director of the Shanghai Astronomical Observatory of the Chinese Academy of Sciences.

Virtual telescopes consisting of observation points distributed around the world successfully “capture” black hole images

The extremely large black hole is the mysterious existence in the universe. This time, through the distribution of global observation points, a virtual telescope with a diameter of the Earth, the Black Hole Incident Vision Telescope, successfully realized the observation at 1.3 mm wavelength and successfully “captured” the black hole image after long-term data analysis.

Due to the high sensitivity required, the eight radio telescopes that make up the global network are distributed in several high altitude areas, including volcanoes in Hawaii and Mexico, the Sierra Nevada in Spain, the Atacama Desert in Chile, and the South Pole. “The resolution of these telescopes is equivalent to a newspaper that can read the Nansha Islands in Mohe, Heilongjiang Province,” said Lu Rusen, a Chinese scientist and researcher at the Shanghai Observatory.

It’s still not enough to “see” and “see” clearly. It’s necessary to “see” the black hole. “When watching TV shows, you have to choose the right channel. The black hole image must also be in the proper band to observe.” Lu Rusen said that the best band is around 1 mm, the black hole halo of this band is the brightest, and the background “noise” is the smallest. .

Shepard Dorman, the head of the international cooperation project and a professor at Harvard University, said that in the past 10 years, technological breakthroughs and cooperation with the Global Observatory have enabled humans to finally open a new window for observing black holes.

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“Event Vision” and “Event Vision Telescope”

The critical range around the black hole where light cannot escape is called the radius of the black hole or the “event horizon.” For this special area, humans use the “virtual telescope” whose diameter is equivalent to the diameter of the earth, and explore the “cluster” left by the black hole.

According to the theory of the famous theoretical physicist Hawking, the black hole “event horizon” is not a single lane with “no go”. Although the object will disappear forever once it is inhaled into the black hole, if it passes for billions of years, the black hole may “bleed out” some clues of inhaled matter.

Because the black hole is very far away and the radius is small, the previous facilities did not have enough resolution to directly observe the black hole, but used indirect methods such as observation of surrounding star motion, accretion disk and jet flow and even gravitational waves.

In order to improve the spatial resolution of the telescope, more than 200 researchers from more than 30 research institutes in many countries around the world have launched a huge observation program. They combine multiple radio telescopes in different regions of the world to form an array for joint observation. This is equivalent to acquiring a giant telescope with a caliber like the size of the Earth. This is the “Event Vision Telescope” project.

The “Event Vision Telescope” actually attempts to observe the “event horizon” of the black hole. After several years of careful preparation, the international research team of the “Event Vision Telescope” project cooperated with the help of eight radio telescopes distributed in many parts of the world, and after nearly two years of data processing and theoretical analysis, it finally succeeded in obtaining the first. Black hole photo.

Experts say that black hole photos will help us understand why black holes can have a profound impact on celestial bodies in the universe.

Black hole – a more incredible object than science fiction

“Facts are sometimes more strange than novels. Black holes best reflect this. It’s more strange than anything the sci-fi writer dreams of.” Hawking wrote in his last book, “Ten Questions: Hawking Meditation.”

The bottomless abyss in the space and time, the hidden gravity traps… The black hole is one of the most striking research topics in the history of astrophysics, and it is also a common “role” in many literary works such as science fiction and movies.

The history of human attention to black holes dates back to the end of the 18th century. About a hundred years after the law of universal gravitation was introduced, the British scientist John Michel first proposed in 1783 that there might be a “dark star” with a gravitational force that could not escape even light. However, at that time astronomers did not discuss this much.

In 1915, Einstein proposed a general theory of relativity that truly “predicted” black holes. But in fact, even Einstein did not believe that black holes existed. However, the scientific community does use the general theory of relativity to calculate that there are such celestial bodies in the universe,

In the 1960s, American astrophysicist John Wheeler first proposed “black hole” as a scientific term, a symbol of its darkness and mystery.

Since then, the scientific community has continued to harvest research on black holes. So far, the existence of black holes has been recognized by most researchers in the astronomical and physics circles.

Before humans first obtained photos of black holes, 2015 was a small peak in black hole research: the gravitational wave detection project provided clear evidence for the existence of black holes.

The scientific community generally believes that the black hole is the most mysterious celestial body in the universe. Almost all the mass is concentrated at the most central “singularity”, and a strong gravitational field is formed around it. Within a certain range, even the light cannot escape. This boundary is called the “Event Vision”. The international organization that released the photo of the black hole is called the “Event Vision Telescope” project.

According to theoretical calculations, there are tens of millions of black holes in the Milky Way. The astronomical community believes that many galaxies have supermassive black holes in the center. For example, the mass of the central black hole of the super-large elliptical galaxy code-named M87 is considered to be about 6.5 billion times that of the sun.

Astronomers divide the black holes in the universe into three categories based on mass: constant-star quality black holes (tens of times to hundreds of solar masses), supermassive black holes (millions of solar mass) and medium-quality black holes (between between).

Although the black hole cannot be directly observed, the gravitational force of the black hole accumulates material near it, and there is usually an accretion disk around it. The accretion disk is very hot and bright, and is clearly contrasted with the black hole, so you can take pictures of the black hole by observing the accretion disk.