First photographic evidence of a supermassive black hole at the heart of our galaxy

PARIS | The international collaboration of EHT astronomers on Thursday pictured the existence of a supermassive black hole at the heart of our galaxy, Sagittarius A*, three years after the first photograph of a black hole located in a distant galaxy.

The black hole’s “silhouette” silhouetted against a glowing disk of matter is reminiscent of the black hole in distant galaxy M87, which is much larger than ours.

Scientists see this as evidence that the same physical mechanisms are at work at the heart of two systems of vastly different sizes.

“I can show you the image of the black hole Sgr A* at the center of the galaxy,” announced Huib Jan Van Langevelde, EHT project leader, to applause at a press conference in Garching, Germany.


First photographic evidence of a supermassive black hole at the heart of our galaxy

Technically, you can’t see a black hole because the object is so dense and its gravitational pull is so strong that even light can’t escape it. But we can observe the material circulating around before it’s swallowed.

“We have direct evidence that this object is a black hole,” said Sara Issaoun of the Harvard Center for Astrophysics, describing “the gas cloud (around the black hole) that emits radio waves that we observed.”


First photographic evidence of a supermassive black hole at the heart of our galaxy

Black holes are considered stellar if they have the mass of a few suns, or supermassive if they have the mass of millions or even billions of suns.

Sagittarius A* (Sgr A*), named for its discovery in the direction of the Sagittarius constellation, has a mass of about four million suns and is 27,000 light-years from Earth. Its existence has been believed since 1974, when an unusual radio source was discovered at the center of the galaxy.

In 2019, the EHT, an international network of eight radioastronomical observatories, brought the historic image of M87*, a supermassive black hole six billion solar masses, to its galaxy Messier 87, located 55 million years ago. At four million solar masses, Sgr A* is a featherweight in the bestiary of supermassive black holes.

The black hole’s “silhouette” silhouetted against a glowing disk of matter is reminiscent of the black hole in distant galaxy M87, which is much larger than our own. Scientists see this as evidence that the same physical mechanisms are at work at the heart of two systems of vastly different sizes.

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