EHT scientist Chi-Kwan (вЂњCKвЂќ) Chan of the Steward Observatory and the Department of Astronomy and the Institute of Data Science at the University of Arizona, USA, explains: This achievement was much more difficult than for the M87, although the Sgr A is much closer to us. вЂњThis tells us that General Relativity governs these objects up close, and any differences we see further away must be due to differences in the material that surrounds the black holes.вЂќ вЂњWe have two completely different types of galaxies and two very different black hole masses, but close to the edge of these black holes they look amazingly similar,вЂќ says Sera Markoff, Co-Chair of the EHT Science Council and a professor of theoretical astrophysics at the University of Amsterdam, the Netherlands. The two black holes look remarkably similar, although the black hole in our galaxy is more than a thousand times smaller and less massive than M87.

The breakthrough follows the release in 2019 of the joint EHT first image of a black hole called M87 in the center of the more distant galaxy Messier 87. EHT observed Sgr A for several nights, collecting data for many consecutive hours, similar to the use of long-term exposure on camera. To image it, the team created the powerful Event Horizon Telescope, which brought together eight existing radio observatories around the world to create a single Earth-sized virtual telescope. The EHT results are published today in a special issue of The Astrophysical Journal Letters.Д«ecause a black hole is about 27,000 light-years from Earth, it seems to us that it is about the same size in the sky as a donut on the moon. вЂњThese unprecedented observations have greatly improved our understanding of what happens at the very centre of our galaxy, and offer new insights on how these giant black holes interact with their surroundings.вЂќ вЂњWe were stunned by how well the size of the ring agreed with predictions from EinsteinвЂ™s Theory of General Relativity,вЂќ said EHT Project Scientist Geoffrey Bower from the Institute of Astronomy and Astrophysics, Academia Sinica, Taipei. The new look captures light bent by the powerful gravity of a black hole that is four million times more massive than our Sun. This suggests that this object вЂ“ known as Sag A (pronounced вЂњsadge-ay-starвЂќ) is a black hole, and todayвЂ™s image is the first direct visual evidence of this.ДЄlthough we cannot see the black hole itself because it is completely dark, the gas glowing around it shows a characteristic feature: a dark central area (so-called вЂњshadowвЂќ), surrounded by a bright annular structure. Earlier, scientists have seen stars orbiting something invisible, compact and very massive in the center of the Milky Way. The image is a long-awaited view of a massive object at the heart of our galaxy. The image was created by a global research team called the Event Horizon Telescope, or EHT Collaboration, using observations from a worldwide network of radio telescopes. This result provides convincing evidence that the object is indeed a black hole, and provides valuable insight into the work of such giants, which are believed to be at the center of most galaxies. During the press conference organized today by the National US Science Foundation, along with the Event Horizon Telescope Collaboration, astronomers have published the first image of a supermassive black hole in the center of our Milky Way galaxy.

First image of a black hole