The first image of a supermassive black hole in the center of the Milky Way

The international Event Horizon Telescope (EHT) group today published the first image of a supermassive black hole in the center of the Milky Way. “It ushered in a new era of black hole physics,” the organization said.

The image was obtained thanks to observations from a worldwide network of radio telescopes. In total, the operations carried out under the study took five years and involved the use of supercomputers to analyze and aggregate the obtained data.

Scientists have already observed stars orbiting the “invisible, compact and very massive” object known as Sagittarius A* at the center of our galaxy. The image posted today helped verify that it is a black hole.

In the image you can’t see the black hole itself because of its complete darkness. However, the surrounding bright gas reveals the dark central portion (called the shadow) surrounded by a ring-shaped structure.

“The new view captures light that is bent by the black hole’s strong gravitational pull, which is four million times larger than our sun,” explains EHT.

This black hole is about 27,000 light-years from Earth, so its size in the sky is equivalent to the size of a “cake on the moon”. To get the image, the researchers had to join eight radio observatories located in the world to form one virtual telescope.

The science team observed Sagittarius A* over several nights, collecting data for many hours at a time. EHT compared this process to using a long shutter speed in a camera.

Another black hole discovered

The achievement comes after the first image of another black hole known as M87* was published in 2019, located in the center of the Messier 87 galaxy.

Although the objects look alike, the Milky Way is about 1,000 times smaller. “We have two completely different types of galaxies and two completely different masses of black holes, but near the edge of these black holes they look surprisingly similar,” said Sera Markov, professor of theoretical astrophysics at the University of Amsterdam in the Netherlands.

Scientists noted that receiving an image from M87* was easier, despite it being located at a greater distance from Earth. The difficulty is that the speed of gas, which orbits near black holes, is the same. Thus, it takes between days and weeks to circle the M87*, while in the case of arc A* it takes several minutes.

“This means that the brightness and pattern of the gas around Sagittarius A* were changing rapidly as seen by the EHT Collaboration, like trying to take a clear photo of a puppy chasing its tail quickly,” said Chi Kwan Chan, a scientist at EHT Collaboration. University of Arizona (USA)

(taken from Russia Today)