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Participants of the Event Horizon Telescope project, large network Radio telescopes have shown for the first time a real image of the shadow of a black hole - in the Messier 87 (M87) galaxy in the constellation Virgo.
Six large press conferences were held simultaneously around the world, where astrophysicists reported on the results of the international project.
One of the project leaders, Luciano Rezzol, noted that the resulting image confirms the existence of the event horizon, that is, it proves the correctness of Albert Einstein’s general theory of relativity.
Scientists combined the power of eight long-wave radio telescopes in different parts of the planet into one large radio telescope-interferometer, since a network of radio telescopes is best suited for such observations. Radio telescopes are located, in particular, in France, Chile, on the island of Hawaii, and the South Pole. The event horizon telescope is named after the boundary of space-time that surrounds a black hole and is the so-called point of no return.
Where did the telescope look?
To explore the vicinity of supermassive black holes at the centers of each galaxy, scientists pointed a network of radio telescopes at two objects - Sagittarius A*, a compact and bright source of radio emission located at the center of our Milky Way galaxy at a distance of about 26 thousand light years from Earth, and at another one black hole - in the center of the elliptical galaxy Messier 87 (M87) in the constellation Virgo, it is located at a distance of 55 million light years from Earth. The black hole in the M87 galaxy is about 6.5 billion times heavier than the Sun and a thousand times heavier than Sagittarius A*.
Continuous observations continued for 10 days in April 2017. Each of the telescopes collected 500 TB of information. It took scientists two years to decipher and analyze the data obtained. When studying the observational results, scientists resorted to the help of supercomputers at the Heistack Observatory (Massachusetts Institute of Technology, USA) and the Max Planck Institute for Radio Astronomy in Bonn (Germany).
The most famous in popular culture The image of a black hole became the image of Gargantua in the film "Interstellar". American astrophysicist Kip Thorne, who received the Nobel Prize for the discovery of gravitational waves, was responsible for creating the visual image of the black hole and its scientific accuracy. In the film, the image is replete with details and optical effects.
It is believed that a black hole is an object with such strong gravity that even light cannot move an infinite distance from it and no body can escape from the black hole. The concept of such objects is associated with the modern view of gravity, Einstein's general theory of relativity, and its representation of gravity through the curvature of space-time.
What astrophysicists wanted to know
It was assumed that collaboration telescopes will help you see the shadow of a black hole. The measurements will test the general theory of relativity and provide further evidence of the existence of black holes. Black holes remain hypothetical objects, but astronomers have no doubt that they exist. Already received a large number of indirect evidence of their existence, ranging from observations of close binary systems to gravitational waves. The first scientifically based image of a black hole was obtained by French astrophysicist Jean-Pierre Luminet in 1979.
However, there have been no direct observations of black holes until now - black holes are small, but at the same time very distant.
Scientists also wanted to find out why some black holes are the centers of colossal sources of radiation - quasars, while others, including Sagittarius A*, behave quietly. In addition, detailed observations will help test exotic hypotheses, such as the wormhole hypothesis.
Black holes are the only cosmic bodies capable of attracting light by gravity. They are also the largest objects in the Universe. We are unlikely to know what happens near their event horizon (known as the “point of no return”) anytime soon. These are the most mysterious places in our world, about which, despite decades of research, very little is still known. This article contains 10 facts that can be called the most intriguing.
1 Black holes do not suck matter into themselves
Many people imagine a black hole as a kind of “space vacuum cleaner”, drawing in the surrounding space. In fact, black holes are ordinary space objects that have an exceptionally strong gravitational field.
If a black hole of the same size arose in the place of the Sun, the Earth would not be pulled in, it would rotate in the same orbit as it does today. Stars located next to black holes lose part of their mass in the form of stellar wind (this happens during the existence of any star) and black holes absorb only this matter.
2 The existence of black holes was predicted by Karl Schwarzschild
Karl Schwarzschild was the first to use Einstein's general theory of relativity to prove the existence of a “point of no return.” Einstein himself did not think about black holes, although his theory predicts their existence.
Schwarzschild made his proposal in 1915, immediately after Einstein published his general theory of relativity. At that time, the term “Schwarzschild radius” arose - this is a value that shows how much you would have to compress an object for it to become a black hole.
Theoretically, anything can become a black hole if compressed enough. The denser the object, the stronger the gravitational field it creates. For example, the Earth would become a black hole if it had the mass of an object the size of a peanut.
3 Black holes can give birth to new universes
The idea that black holes can give birth to new universes seems absurd (especially since we are still not sure about the existence of other universes). Nevertheless, such theories are actively being developed by scientists.
A very simplified version of one of these theories is as follows. Our world has extremely favorable conditions for the emergence of life in it. If any of the physical constants changed even a little, we would not be in this world. The singularity of black holes overrides the normal laws of physics and could (at least in theory) give rise to a new universe that will be different from ours.
4 Black Holes Can Turn You (And Anything) Into Spaghetti
Black holes stretch objects that are near them. These objects begin to resemble spaghetti (there is even a special term - “spaghettification”).
This happens due to the way gravity works. At the moment, your legs are closer to the center of the Earth than your head, so they are attracted more strongly. On the surface of a black hole, the difference in gravity begins to work against you. The legs are attracted to the center of the black hole faster and faster, so that the upper half of the body cannot keep up with them. Result: spaghettification!
5 Black holes evaporate over time
Black holes not only absorb stellar wind, but also evaporate. This phenomenon was discovered in 1974 and was called Hawking radiation (after Stephen Hawking, who made the discovery).
Over time, the black hole can release all its mass into the surrounding space along with this radiation and disappear.
6 Black holes slow down time near them
As you approach the event horizon, time slows down. To understand why this happens, we need to look at the “twin paradox,” a thought experiment often used to illustrate the basic principles of Einstein's theory of general relativity.
One of the twin brothers remains on Earth, and the second flies off on a space journey, moving at the speed of light. Returning to Earth, the twin discovers that his brother has aged more than he has because time moves slower when traveling near the speed of light.
As you approach the event horizon of a black hole, you will move at such a rate high speed that time will slow down for you.
7 Black holes are the most advanced energy systems
Black holes generate energy better than the Sun and other stars. This is due to the matter orbiting around them. Crossing the event horizon at enormous speed, matter in the orbit of a black hole heats up to extremely high temperatures. This is called black body radiation.
For comparison, nuclear fusion converts 0.7% of matter into energy. Near a black hole, 10% of matter becomes energy!
8 Black holes bend the space around them
Space can be thought of as a stretched rubber plate with lines drawn on it. If you put an object on the record, it will change its shape. Black holes work the same way. Their extreme mass attracts everything, including light (the rays of which, to continue the analogy, could be called lines on a plate).
9 Black holes limit the number of stars in the Universe
Stars arise from gas clouds. For star formation to begin, the cloud must cool.
The radiation from black bodies prevents gas clouds from cooling and prevents stars from appearing.
10 Theoretically, any object can become a black hole
The only difference between our Sun and a black hole is the force of gravity. At the center of a black hole it is much stronger than at the center of a star. If our Sun were compressed to about five kilometers in diameter, it could be a black hole.
Theoretically, anything can become a black hole. In practice, we know that black holes arise only as a result of the collapse of huge stars that exceed the Sun in mass by 20-30 times.
