For the first time, astronomers have been able to image the black hole at the center of our galaxy, the Milky Way. The image presented this Thursday (05.12.2022) shows exactly the circumference of the supermassive black hole, since the objects themselves are invisible by nature. The image was made possible by observations made with the “Event Horizon Telescope” (EHT), a combination of eight radio observatories on four continents to form a type of super telescope.
The image of the collective monster at the heart of our galaxy is only the second image taken from a black hole. Shows a dark central area surrounded by a shiny circular structure. So far, books and illustrations have only shown illustrations of the black hole at the center of the Milky Way.
The Max Planck Institute for Radio Astronomy (MPIfR) in Bonn is heavily involved in the EHT. The researchers presented the results of their observations in a special issue of Astrophysical Journal Letters.
Sagittarius A*
The image of Sagittarius A* – the name of the black hole – matches the predictions of Albert Einstein’s general theory of relativity for a black hole four million times the mass of our sun, they report. The hole may be spinning.
Also involved in the measurements was the Institute for Millimeter-Range Radio Astronomy (IRAM), a Franco-German-Spanish collaboration with the 30-meter telescope in Spain and the NOEMA interferometer in France.
The first image of a black hole in 2019
In 2019, EHT researchers revealed the first image of the vicinity of a black hole: a bright ring with a dark center. It is the largest and most massive black hole located at the center of the galaxy M87, about 55 million light-years away.
This image shows the Atacama Large Millimeter/ Millimeter Array (ALMA) observing the Milky Way and the location of Sagittarius A*.
Although the black hole at the center of the Milky Way is much closer to Earth, at a distance of about 27,000 light-years, the observations proved difficult. “The radiation from the black hole at M87 is constant over hours,” explained Anton Zonsus of Bonn MPIfR, one of the main promoters of the EHT project.
“On the other hand, the galactic center body is already changing within a few minutes. Therefore, we had to develop completely new methods of evaluation,” he added.
The black hole is at the center of most galaxies
Astronomers assume that there is a black hole at the center of most galaxies. Because of their massive mass, black holes do not allow light to escape, which makes them almost invisible. However, before the matter is attracted to the black hole, it gets very hot and then strongly radiates. This distinctive reddish glow can be seen in the photographs.
The name “Event Horizon Telescope” (“Event Horizon Telescope”) refers to the ability to optically penetrate the event horizon of a black hole, the limit beyond which light cannot escape a gravitational monster. Thus the hole appears above it. black.
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