Astronomers have finally spotted the center of the Milky Way galaxy and have unmasked a giant black hole, a celestial vortex 26,000 light-years from Earth that would otherwise be hidden from view.
An international team of researchers released a snapshot of the supermassive black hole known as Sagittarius A* on Thursday.† spied on by the power of eight linked radio dishes from around the world that together can penetrate through gas clouds in space. While black holes cannot be seen by definition – light cannot travel fast enough to escape their clutches – Sagittarius A* revealed itself in the form of a black shadow surrounded by the bright glow of the gas and debris swirling around its perimeter .
The image showed a region of deep space reminiscent of a solar eclipse – a dark circle shrouded in a radiant red-orange beam. The image was colored so that the human eye could see it.
Until three years ago, any image of a black hole was just an artist’s interpretation or computer model of what the spinning, spacetime-bending phenomenon might look like. This object, seen in the photo at the top of this story, is the real thing, each pixel represents a huge effort: hundreds of scientists from 80 institutions around the world, working together to collect, process and piece together fragments of data.
The breakthrough was also published in the scientific journal Astrophysical Journal Letters† Spokespersons for the Event Horizon Telescope, the international collaboration of 300 scientists who worked on the feat, held simultaneous press conferences in at least seven countries to share the news, including the United States at the National Press Club in the nation’s capital.
The image of Sagittarius A*, pronounced “Sagittarius A-Star,” is a monumental achievement, the second time scientists have overcome the barrier of invisibility to glimpse a black hole. The first photo, unveiled in April 2019, showed the black hole at the center of the Messier 87 galaxy an easier target to capture due to its size, despite being much further away, about 53 million light-years away. . Astronomers say a black hole called M87* is the size of Earth’s eight-planet solar system.
The second photo offers strong confirmation to the scientific community, said Feryal Özel, a professor of astronomy and physics at the University of Arizona.
“Now we know it wasn’t a coincidence — it wasn’t some aspect of the environment that happened to look like the ring we expected to see,” she said at the Washington, D.C. news event. what we see is the heart of the black hole, the point of no return. These two images are similar because they are the result of fundamental gravitational forces.”
Astronomers see the first supermassive black hole as it grows up
This graph shows how much larger the supermassive black hole in the galaxy M87 is than Sagittarius A* (located at the center of our Milky Way Galaxy).
Credit: National Science Foundation/Keyi “Onyx” Li
Sagittarius A*† or Sgr A* for short, is considerably smaller, about 27 million miles in diameter, but it’s not a beeping sound. Scientists estimate that it is 4 million times more massive than the Sun. To make a hard-to-understand number even more inscrutable, imagine this: The mass of the sun is equal to 333,000 Earths.
Its Milky Way home, a spiral galaxy, is fairly flat, but the center sinks down where the supermassive black hole is. All around it, stars fly in different directions. But the hole, often anthropomorphized in pop culture as a space monster, is actually quite “soft,” researchers say, and consumes relatively little of its environment.
Black holes are some of the most elusive things in space. The most common kind, called a stellar black hole, is often thought to be the result of a massive star dying during a supernova explosion. The material from the star then collapses on itself and condenses into a relatively small area.
But how supermassive black holes, millions to billions of times more massive than the Sun, shape is even more mysterious than typical stellar black holes. Many astrophysicists and cosmologists believe that these behemoths lurk at the center of virtually all galaxies. Recent observations from the Hubble Space Telescope have bolstered the theory that supermassive black holes originate in the dusty cores of starburst galaxies, where new stars are quickly produced, but scientists are still trying to solve the problem.
Black holes have no surfaces, like on a planet or star. Instead, they have a boundary called an “event horizon.” It is a point of no return. If something gets too close, it will fall in, never to escape the gravity of the hole.
Before the May 12 breakthrough, the Event Horizon Telescope team released the first image of a black hole in the Messier 87 galaxy in April 2019.
Credit: Chip Somodevilla/Getty Images
If M87* proved that black holes were not science fiction, Sgr A* is evidence of decades of increasing observational science. Before the first picture of a black hole, scientists inferred the presence of a hole in space by detecting its impact on nearby stars and gas. Albert Einstein, whose theory of general relativity predicted black holes more than a century ago, and Stephen Hawking, a cosmologist who devoted much of his career to mathematically proving their existence, are among the many figures who paved the way for the revelation of Thursday.
If M87* provided proof that black holes weren’t science fiction, Sgr A* is proof of decades of increasing observational science.
Sgr A* is exciting for scientists because it just is, said Michael Johnson of the Harvard Smithsonian Center for Astrophysics. the central supermassive black hole is representative of many others in the universe, allowing experts to learn more about these mysterious space objects.
Despite their visual similarities — one flaming donut versus another flaming donut — the two black holes couldn’t be more different, scientists say. M87* accumulates matter at a significantly faster rate, but the Milky Way’s central black hole changes appearance more quickly: it takes only a few minutes for gas to completely revolve around it, while orbiting its predecessor takes about two weeks.
In addition, the first black hole photographed launches a giant beam of radiation that extends to the edge of its galaxy, while Sgr A* does not.
To collect the massive amount of data needed to process the new image, the Event Horizon Telescope used a technique called very-long-baseline interferometry, which synchronizes observatories around the world and takes advantage of the Earth’s rotation to create one virtual image. planet-sized telescope. Together, the instruments were able to view the sky with a view similar to that needed to read a New York newspaper from Paris, the organization said.
At the time of the 2019 black hole announcement, Event Horizon Telescope employees said they had also tried to capture an image of this supermassive black hole, but the team had been unable to get a clear image. As one of the most studied supermassive black holes in the universe, that came as a disappointment to many astrophysicists who longed to gaze at our galaxy’s own navel.
“For me personally, I met it 20 years ago and I love it and have been trying to understand it ever since,” Özel said on Thursday.
This time, scientists added the South Pole Telescope, which was not used in the M87* image, to the virtual telescope array to improve the resolution of their imaging. Researchers collected five petabytes of data, about 2.5 trillion pages of printed text, to get even a glimpse of this black hole, said Dom Pesce, a member of the telescope team.
Put another way, that’s the equivalent amount of data in about 100 million TikTok videos, said Vincent Fish, a research scientist at MIT Haystack Observatory. That’s way too much to stream over the Internet, so scientists had to send hundreds of hard drives to two centers in western Massachusetts and Bonn, Germany, where supercomputers could process the raw data.
Credit: Daniel Michalik/National Science Foundation
Admittedly, the Sgr A* photo is blurry. Johnson compared the blur to peering through frosted glass. Radio waves with crucial image details are scattered, making the sharp outline of the hole more like a jelly ring. To fix that, the telescopes must either be further apart or reach higher frequencies, he said.
“We don’t think the black hole is actually a blurry image in the sky,” Johnson said. “We’re just at our breaking point here.”
“We don’t think the black hole is actually a blurry image in the sky.”
With funding from the National Science Foundation and other groups, scientists plan to improve their technology to dramatically sharpen the picture.
Another next step for the collaboration is to try to turn these still images into videos so scientists can observe how gas falls toward the black holes event horizon. That project could be completed sometime after 2024, they said.
But just in case anyone out there isn’t impressed by another burning donut, Katie Bouman, an assistant professor of astronomy at Caltech, recalled how much data is packed into the image.
“This image is actually one of the sharpest images you’ve ever seen,” she said.