The photo provides proof that there really is a huge black hole in the center of the galaxy, around which all the objects of the Milky Way, including the Sun, and with it the Earth revolve.
Scientists suggest that such objects are located at the centers of most galaxies. Such images should provide valuable information about how such giants live.
“Scientists have previously observed stars orbiting something invisible, compact and very massive at the center of the Milky Way. The data strongly indicated that this object – known as Sagittarius A * (Sagittarius A *, Sgr A *) – is a black hole. Today’s images represent the first direct visual confirmation of this,” the UNT said in a statement.
According to experts, the black hole itself, of course, cannot be seen in the pictures, since it is absolutely black. However, the luminous gas around it adds up to a characteristic picture: a dark central region, which is called the “shadow”, and a bright ring-shaped structure surrounding it.
“We were amazed at how well the ring’s dimensions matched the predictions of Einstein’s general theory of relativity. These unprecedented observations have greatly improved our understanding of the processes that take place at the center of our galaxy and have provided new clues to how black holes interact with their surroundings,” said UNT collaboration scientist Jeffrey Bauer.
The black hole Sgr A * is located at a distance of 27 thousand light years from the Earth, in mass it is 4 million times greater than the Sun, the size of the ring visible in the image approximately corresponds to the orbit of Mercury, that is, about 60 million km, the radius of the event horizon is about 6 million km. However, due to the large distance from the Earth, the black hole, according to EHT scientists, appears in the sky as a tiny dot – like a donut that you are trying to make out on the surface of the moon.
To image this object, astrophysicists used a network of eight observatories in different parts of the Earth, which together form a planet-sized virtual telescope called the Event Horizon Telescope. The data was collected over “multiple nights” for many hours at a time, comparable to long-exposure photography, the scientists say. Then the information was processed by supercomputers for a long time.
Similarly, in 2019, we managed to get the first ever image of the black hole M87 *, however this object is outside our galaxy and is much larger than Sgr A *, so it was actually easier to shoot it, because it is close and not so big Sgr A* turned out to be much more dynamic and changeable for the observer.
“This means that the brightness and patterns of hot gas around Sgr A* changed rapidly during the observation by the UNT collaboration. It was like trying to get a clear photo of a puppy chasing its own tail,” Chi-Kwan Chan from the University of Arizona says about the work of scientists.
The resulting images are the result of bringing together different images, their “arithmetic mean”. The corresponding work took about five years, and the resulting portrait of Sgr A *, as noted by the co-chair of the scientific council of UNT Sera Markoff, surprised scientists by showing many similarities between the two black holes – M87 * and Sgr A *.
“We have two galaxies of completely different types and two very different black holes in mass, but closer to their edges they look surprisingly similar,” she says.
Collaborator Keiichi Asada noted that scientists can now compare the differences between two supermassive black holes, which should provide invaluable insights into how such objects function. Experts have a very large and very distant hole M87*, and a closer one and located at the other end of the Sgr A* size range.
The work to detect a supermassive compact object at the center of the Milky Way – this object turned out to be a black hole – was awarded the Nobel Prize in Physics in 2020. The object itself was found by tracking the movement of stars at the end of the last century.
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