this afternoon, For the first time, the world was able to see an image of a black hole A supermassive located in the center of our Milky Way galaxy.
The Milky Way is a spiral galaxy Contains at least 100 billion stars. When seen from above or from below, it resembles a spinning wheel, as our Sun is located in one of the spiral arms and Arch A* is located in the center.
Astronomers think so Almost all galaxies, including our own, have giant black holes at their centers, from which matter and light cannot escape, making them extremely difficult to photograph. Experts said gravity bends and twists light chaotically as it sinks into the abyss of sheltered gas and dust that make up the black hole. The artificially colored image was distributed today by the international consortium that maintains the Event Horizon Telescope (EHT), a The collaboration of 8 simultaneous radio telescopes in different parts of the world. In previous attempts, our galaxy’s black hole was too accelerated to get a good picture.
Ferial Ozil of the University of Arizona announced the new look of what he called “The gentle giant at the center of our galaxyThe black hole in the Milky Way is called Sagittarius A (star) and is located near the edge of the constellations Sagittarius and Scorpio.. Its mass is 4 million times the mass of the Sun. This is not the first image of a black hole. The same group distributed the first in 2019, from a galaxy 53 million light-years away. The Milky Way’s black hole is much closer: it is about 27,000 light-years away from you. One light year equals 9.5 billion kilometres.
The project cost approximately $60 million. With a contribution of 28 million from the US National Science Foundation.
EHT International Cooperation Project (Event Horizon Telescope) is a system Create a virtual telescope the size of the Earth This allowed the discovery of the first supermassive black hole in 2019, in the galaxy M87, and now the hole in the center of the Milky Way, Sagittarius A*.
It was launched in 2015, This international collaboration of 80 astronomy institutes has set itself a major challenge Because observing a black hole is, by definition, impossible, because no light can escape from it. The The EHT has crossed the obstacle by discovering a cloud of superheated plasma orbiting a black hole Before passing the event horizon, the place from which nothing can come out again, not even light, due to intense gravity. “The silhouette of a black hole can be seen against a background of glowing gas and dust.Frédéric Gieth, French scientist at the National Center for Scientific Research (CNRS) and director of the Institute for Millimeter Radio Astronomy (IRAM) explains. Founded by CNRS and Germany’s Max Planck Institute in 2015, IRAM is a major player in EHT, which shot the M87* in 2019, and now the bow A* (Sgr A*).
But, To achieve these feats, astronomers had to overcome many obstacles. The cloud of matter surrounding black holes is visible only on a specific range of millimeter radio waves.In order to capture it, a radio telescope is needed, a dish-shaped antenna similar to the antenna used for satellite television, only much larger, because the sharpness of the instrument is closely dependent on size, due to colossal situations and other obstacles.
M87 * 55 million light years from Earth, while Sgr A * 27,000 light years away. But the latter is much smaller, and when viewed from Earth, it hides behind huge interstellar clouds of dust and gas. No radio telescope in existence has had enough resolution to bring out their silhouettes. Scientists then resorted to the principle of interferometry, in which a network of antennas located in different parts of the planet monitor the same sector of the sky at the same moment. Supercomputers combine data obtained by various radio telescopes, allowing to obtain an image as if obtained by a single antenna the size of the Earth.
The EHT experiment took the exercise even further using interferometry but with a larger base (VLBI), i.e. forming a network of Eight radio astronomical observatories stretching from Hawaii in the Pacific Ocean to Spain – where the IRAM antenna is located – pass through the United States; And from Greenland to the Antarctic, passing through Mexico and Chile. It is a challenge, because it must have good weather at the same time in all places in the network, and to achieve this synchronization in microseconds, each place is equipped with an atomic clock.
“When we do it on a global scale, we find ourselves with a huge antenna about 10,000 kilometers in diameter,” says Frederic Gith. The combined and simultaneous data from the eight observatories allowed us to build the picture we observe today and spread around the world. Einstein’s general theory of relativity has so far failed to explain what happens in a black hole on a very small scale. A black hole is “the most extreme, chaotic and turbulent environment,” said German astrophysicist Heinau Falk. But thanks to the EHT, aspects of this basic theory can now be tested.