Astronomers present first picture of black hole at center of galaxy
BERLIN — Astronomers on Thursday presented an image of the supermassive black hole at the center of the Milky Way for the first time.
The object known as Sagittarius A* is 27,000 light-years from Earth, the mission scientists said in a statement.
The image shows the surroundings of the supermassive black hole, as the object itself is invisible by nature, and was captured by the Event Horizon Telescope (EHT), a combination of eight radio observatories on four continents, which together form a kind of super telescope.
It shows a dark central region surrounded by a bright ring-shaped structure.
In 2019, the EHT researchers presented the first ever image of the immediate surroundings of a black hole, which also depicted a glowing ring with a dark center.
The 2019 image was from a far larger and more massive black hole at the center of the galaxy M87, some 55 million light years away.
Although the black hole at the center of the Milky Way is much closer to Earth, observations proved difficult.
“The radiation of the black hole of the M87 is constant over hours. The object at the center of the Milky Way, on the other hand, changes over the course of a few minutes,” explained Anton Zensus, astrophysicist and director at the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn said.
“Therefore we had to develop completely new methods for the evaluation,” he said.
Astronomers assume that there is a black hole at the center of most galaxies. Due to their extreme mass, they do not allow light to escape, making them practically invisible.
However, before matter is drawn into a black hole, it strongly heats up and radiates brightly. This characteristic glow can be seen in a reddish color in the images.
“We were stunned by how well the size of the ring agreed with predictions from Einstein’s Theory of General Relativity,” said EHT Project Scientist Geoffrey Bower from the Institute of Astronomy and Astrophysics, Academia Sinica, Taipei.
“These unprecedented observations have greatly improved our understanding of what happens at the very center of our galaxy, and offer new insights on how these giant black holes interact with their surroundings.”