For years, scientists have dreamed of looking intoin the heart of the Milky Way. Surprisingly, their dream finally came true: using the network of observatories of the Event Horizon Telescope (EHT) project, astronomers published the first ever image of Sagittarius A * - a supermassive black hole at the center of the Galaxy. Its mass exceeds the solar mass by 4 million times. This space monster is located at a distance of about 26 thousand light years from Earth and is technically impossible to see. But since black holes attract everything in their vicinity, they are surrounded by luminous destroyed matter that circles over the abyss at a speed close to the speed of light.
Dark central area in the imagecalled "shadow". It was made visible thanks to the EHT network of radio telescopes, which recorded light bent by the gravity of a black hole at the very heart of our galaxy.
- 1 Heart of the Galaxy
- 2 What do black holes eat?
- 3 Big difference
- 4 Event Horizon Telescope
Heart of the Galaxy
Black holes are objects inspace-time, the gravitational attraction of which absorbs everything that is nearby. These cosmic monsters attract light and matter that revolve around the black hole, bending space and time around it, casting a shadow on the luminous matter.
It is technically impossible to see the black hole itself -neither light nor matter can break out of it. However, the image of Sagittarius A * obtained in the course of the work is convincing evidence that a black hole is indeed located at the center of our Galaxy.
The team spent five years analyzing the data,received in April 2017. The image was obtained thanks to the network of radio telescopes Event Horizon telescope (EHT), which covers the territory from Antarctica to Spain and Chile.
Earlier in 2019, researchers received the firstimage of a black hole in the galaxy Messier 87. To the untrained eye, the image of Sagittarius A* certainly looks like an image of the black hole M87, but the EHT team says the two objects are very different from each other.
Personally, I am pleased with the fact that we are finallyhave proven the existence of a black hole at the center of our galaxy,” Professor Ziri Yunsi, a member of the EHT collaboration from University College London, told The Guardian.
Astronomers believe that at the center of almost allgalaxies in the universe, including the Milky Way, are black holes. Getting their images is not easy: when light is sucked into the abyss along with superheated gas and dust, it bends and twists under the influence of gravity.
By the way, starting in 2019, scientists intend to removethe first ever video of a black hole and how it absorbs all the objects around it. We talked about the revolutionary plans of astronomers in more detail in this article, we recommend reading it.
What do black holes eat
During a press conference on May 12, astronomerspresented an image taken with the EHT, a network of eight synchronized radio telescopes around the world. But creating a good and reliable image of Sagittarius A* is not an easy task - all previous attempts have shown that the black hole at the center of the Milky Way is behaving restlessly.
But despite the lack of stability,The resulting image of Sagittarius A* once again confirmed the predictions of Albert Einstein and his General Theory of Relativity (GR): the black hole at the center of our Galaxy corresponds to the dimensions predicted by Einstein's equations. You can imagine the size of this space monster by comparing it with the orbit of Mercury around the Sun.
See also: Can gravitational waves solve the crisis of cosmology?
As a rule, black holes in the hearts of galaxiesabsorb all nearby objects in huge quantities, unlike Sagittarius A *, which eats rather modestly. According to the researchers, our black hole is "on a starvation diet" - very little material gets into its center, but it is this feature that allows astronomers to look into the very heart of the Galaxy.
The very first image of the shadow of a black hole inthe center of the galaxy Messier 87, located 53 million light-years from Earth, was published in 2019. As in the case of M87, Sagittarius A* was imaged using eight ground-based EHT radio telescopes that work as a single unit.
Unlike Sagittarius A*, black hole M87is one of the largest in the universe. Its mass exceeds the solar mass by 6.5 billion times and absorbs a huge amount of matter, releasing energy into outer space. More about the black hole in the Messier 87 galaxy, we talked about earlier.
Returning to Sagittarius A *, it should be noted thatthat the data obtained using the EHT gives us an idea of a more standard state of black holes: quiet and still. According to astronomers, the behavior of a black hole in the Milky Way is common for many galaxies.
“The observations can be compared to trying to photograph a puppy chasing its own tail with a slow shutter speed camera,” the researchers explain.
Since Sagittarius A* is a relatively small black hole, the dust and gas in its accretion disk orbits, creating a moving target from one observation to the next. Recall that accretion disk A black hole is a large mass of matter that heats up to enormous temperatures and revolves around a monster at the galactic center.
This is interesting: What are the stars orbiting the supermassive black hole at the center of our galaxy hiding?
Event horizon telescope
The EHT Event Horizon Telescope capturesRadiation emitted by particles inside the black hole's accretion disk: The spotted halo in the images shows light being bent by the black hole's powerful gravity, which is 4 million times more massive than our Sun.
Event Horizon Telescope is a global radio interferometer withextra long base. The EHT got its name in honor of the "event horizon" - a point in space that even light cannot leave. In simple terms, the EHT, in fact, forms a single virtual telescope "the size of the Earth."
The goal of future research may be the "Unicorn" - the closest black hole to Earth
This happens when all eight radio telescopeson different continents are synchronized with each other using atomic clocks and supercomputers for data processing. The cost of this unique project is about 60 million dollars, 28 of which came from the US National Science Foundation.
The photo of the shadow of Sagittarius A* is the resulttechnically complex observations and innovative computational algorithms,” Katherine Bowman of the California Institute of Technology said at a press conference.
Observations of the object were carried out for five whole years,since 2017, and the resulting image of Sagittarius A * is the result of the work of more than 300 scientists from 80 countries of the world. The image, presented at the official press conference on May 12, 2022, is composed of several thousand images of this space monster.
Read even more interesting articles about stars, galaxies and the secrets of the Universe on our channel in Yandex.Zen. There are regularly published articles that are not on the site.
Ultimately, scientists hope that the observationbehind a range of black holes, both quite calm and turbulent, can help answer numerous questions about the evolution of galaxies - today there is no answer to the question of which came first - a galaxy or a black hole - there is no.
Another important aspect of the new discovery isit is an emotional connection with the heart of the native Galaxy. Agree, there is something exciting in the fact that for the first time in history the world enjoys a snapshot of the center of the Milky Way. The results of the EHT team are published in a special issue of the scientific journal Astrophysical Journal Letters.
The EHT team is now working on expanding the telescope network and is carrying out upgrades that in the future will allow you to get even more stunning images and even movies about black holes.According to the researchers, the work on the project unites: language, continents and even galaxies cannot stand in the way of the great opportunities of mankind. After all, in order to achieve revolutionary discoveries, we must work together and work for the common good. Do you agree?