Astronomers reveal the first image of the black hole at the center of the Milky Way



South African and international astronomers have revealed a stunning first image of the black hole at the heart of our galaxy.

This was presented Wednesday at the Witwatersrand Planetarium at one of five international press conferences held simultaneously in Munich, Washington DC, Santiago de Chile, Mexico City, Tokyo and Taipei.

The image was produced by a global research team called the Event Horizon Telescope (EHT) – more than 300 scientists around the world who produced the first image of a black hole in another galaxy in 2019.

A worldwide network of radio telescopes was used to produce the image. It revealed a bright ring structure with a dark central region defined as the shadow of the black hole. According to the scientists involved in the EHT project, the result provided overwhelming evidence that the object was indeed a black hole and provided valuable clues to the functioning of such giants, which were thought to reside at the center of most galaxies.

The image was a long overdue look at the huge object that lay right in the center of our galaxy. Scientists had already seen stars orbiting something invisible, dense and massive in the center of the Milky Way.

This strongly suggested that this object, known as Sagittarius A, was a black hole and the image provided the first direct visual evidence of this. This was followed by 10 days of rumors and speculations about what exactly would be announced. EHT project scientist Geoffrey Bower of the Taipei Institute of Astronomy and Astrophysics (IAA) said he was amazed at how well the size of the ring fits in well with Albert Einstein’s predictions.

Bower said that although people cannot see the black hole itself, because it is completely dark and contained glowing gas around it, it revealed a “telltale signature” that was a dark central region called a “shadow” surrounded by a ring of light. – as a structure. She said the new view captured light bent by the black hole’s powerful gravity, which was four million times more massive than the sun.

“These unprecedented observations have greatly improved our understanding of what happens at the center of our galaxy and offer new insights into how these giant black holes interact with their surroundings.”

Witwatersrand director at the Center for Astrophysics Roger Deane said black holes knew about their galaxies and galaxies knew about their black holes. The second largest black hole seen from Earth was about 1,000 times larger than the Milky Way’s black hole, but 2,000 times further away.

Deane said the black hole was about 27,000 light-years from earth and appeared to be about the same size in the sky as a donut on the moon. To imagine this, the team created the powerful EHT, which linked eight existing radio observatories around the planet to form a single “earth-sized” virtual telescope.

Sera Markoff, co-chair of the EHT science council, said the two black holes looked remarkably similar, even though the galaxy’s black hole was more than a thousand times smaller and less massive than M87. The release of the first image of a black hole was called M87 *.

“We have two completely different types of galaxies and two very different black hole masses, but near the edge of these black holes they look strikingly similar,” he said.

“This tells us that general relativity rules these objects closely and any differences we see further away must be due to differences in the material surrounding the black holes.”

Scientists were particularly excited to have images of two very different sized black holes. IAA scientist EHT Keiichi Asada said he was able to study the differences between these two huge black holes.

“We have images for two black holes, one at the large end and one at the small end of supermassive black holes in the universe and we can go much further in testing how gravity behaves in these extreme environments than ever,” he said. he said she.

Deane added that southern Africa has a distinct geographic advantage in hosting new EHT telescopes, particularly for shooting footage of the Milky Way’s supermassive black hole.