Scientists from the Event Horizon Telescope (EHT) initiative, an international effort to link radio dishes across the world to study black holes, have shown off the first image of the supermassive black hole lurking at the center of our galaxy, called Sagittarius A*.
It's a groundbreaking moment in astrophysics, as their results confirm the black hole's existence once and for all, and provide support for Einstein's theory of general relativity.
While Sagittarius A* — or Sgr A*, pronounced "sadge-ay-star" — is only 25,800 light-years away and 4.3 million times the mass of the Sun, it's still incredibly difficult to image directly. It's the approximate equivalent, to put things in perspective, of snapping a picture of a tennis ball on the Moon.
The admittedly rather blurry image shows the glowing gas surrounding the black hole, with the light itself being bent by its mighty gravitational force. The awe, though, is real, with one science writer quipping that the black hole is "definitely the Eye of Sauron."
We finally have the first look at our Milky Way black hole, Sagittarius A*. It’s the dawn of a new era of black hole physics. Credit: EHT Collaboration. #OurBlackHole #SgrABlackHole
Link: https://t.co/Ax7ECRVg8A pic.twitter.com/LRWizSYOy9
— Event Horizon 'Scope (@ehtelescope) May 12, 2022
"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 at Academia Sinica in Taipei, Taiwan, in a statement.
"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," he added.
The team's results were published today in the journal The Astrophysical Journal Letters.
In 2019, the EHT team shared the first image ever taken of a black hole, a snapshot of the event horizon of the supermassive black hole M87*, which is much larger at 6.5 billion times the mass of the Sun, and much further away, lurking in the Messier 87 galaxy 55 million light-years from Earth.
The similarities between the two black holes astonished the scientists.
"We 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," said Sera Markoff, co-chair of the EHT Science Council and a professor of theoretical astrophysics at the University of Amsterdam in the Netherlands, in the statement.
"This 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," Markoff added.
Since their sizes are orders of magnitudes apart, the two images allow scientists to gain crucial insights into the laws of physics that govern their nature.
"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 — so we can go a lot further in testing how gravity behaves in these extreme environments than ever before," said EHT scientist Keiichi Asada from the Institute of Astronomy and Astrophysics, Academia Sinica, Taipei, in the statement.
The team is now excited to get clearer images — and even perhaps movies — of black holes in the future by making several technological upgrades.
Featured image updated to show the latest image from the EHT project.
READ MORE: Astronomers reveal first image of the black hole at the heart of our galaxy [Event Horizon Telescope]
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