For decades, astronomers have wondered what lies at the heart of the Milky Way. Today, scientists have revealed the first photo of the supermassive black hole that lurks there, offering a completely new view of our galaxy.
The historic image of what scientists call Sagittarius A*, captured by an array of telescopes around the world called the Event Horizon Telescope (EHT) and released on Thursday (May 12), confirms a black hole at the heart of the Via Milky way feeding on hydrogen gas. The EHT is most famous for capturing the first image of M87’s supermassive black hole in 2019, but for the project’s scientists, today’s image is an even more remarkable milestone.
“I wish I could tell you that the second time is just as good as the first image of black holes. But that wouldn’t be true. In fact, it’s better,” Feryal Özel, EHT modeling leader and professor of astronomy and astrophysics at the University of Arizona, said during a press conference on Thursday.
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Özel has been examining Sgr A*, as the black hole is nicknamed, for 22 years since his graduate student days. The image of a second black hole with EHT shows that the telescope’s capabilities “were not a coincidence”, added Özel, saying: “We now know that in both cases, what we see is the heart of the black hole – the point of no return. . “
It also felt like a reunion of old friends, she said, comparing it to meeting a friend online in real life for the first time. “I kind of had an idea in my head about what it would be like; we were chatting online, and then I was like, ‘Oh, you’re real!'” Özel said, as the room laughed. “It feels really good.”
Still, years of research could not fully prepare the team for the emotional impact of the discovery. “I remember seeing this and kind of walking around kind of stunned,” team member Michael Johnson, an astrophysicist at the Harvard-Smithsonian Center for Astrophysics and professor in the department of astronomy at Harvard University, reminded reporters.
“You look at this image,” Johnson added, “and that hole in the center is 4 million solar masses. That’s amazing.”
Katherine Bouman, a Rosenberg scholar and assistant professor of computing and mathematical sciences at the California Institute of Technology, paid tribute to the variety of disciplines and people needed to capture Sgr A*.
“It’s amazing what we’ve been able to do, bringing together people with a lot of different expertise,” Bouman said at the same press conference.
The EHT team was looking at Sgr A* long before today’s reveal, but did not generate an image from the initial data. Sgr A* was found to be a harder target to reveal than the black hole at the heart of M87, although it is only half the distance away.
That’s because Sgr A* is a relatively light supermassive black hole, with a mass of 4.3 million suns, with a more dynamic environment than the 6.5 billion solar-mass M87, the scientists said. But now the new images show that it was indeed possible to capture our galaxy’s black hole.
“As a member of the collaboration, I am very proud that we were able to not let all these challenges that were there from the beginning stop us from continuing,” said Bouman.
“We weren’t afraid of uncertainty and all the missing information. We found ways to deal with it,” he added. “And for that, I’m really, really happy and really honored to be able to work with the people here. I think it’s super exciting. I mean – what’s cooler than seeing the black hole at the center of our own Milky Way?”