Milky Way black hole wind mystery may be solved

Scientists say they have detected evidence of cosmic-scale wind coming from a supermassive black hole at the center of our galaxy, potentially solving one of the longest-standing mysteries in astronomy.

Sagittarius A*, a gigantic black hole with the mass of about 4 million suns, has puzzled the scientific community for more than 50 years. The laws of physics dictate that, like all black holes, the object should not just consume material but also expel some in the form of wind or jets. However, Sagittarius A* has been strangely quiet. Despite decades of searching, scientists could only gather clues of wind eruptions dating back more than 20,000 years but none more recent.

“This is our closest and best studied black hole,” said Mark Gorski, a research assistant professor at Northwestern University in Evanston, Illinois. “It’s the one we can resolve and see all of the physics around it, and yet it didn’t seem to have a wind. Every black hole in the universe behaves in this one way, but the one that’s closest to us is different. That was a huge problem.”

Now, after five years of observations, Gorski and Lena Murchikova, an assistant professor of physics and astronomy at Northwestern, believe they have found signs of the missing wind. The duo created a highly detailed image of the black hole’s surrounding area. Within the image, Gorski and Murchikova spotted a large, cone-shaped cavity devoid of cold gas. 

The feature could only have been sculpted by a wind of hot gas coming directly from the object itself, according to the researchers, who are co-lead authors of a study on the discovery published June 4 in the journal The Astrophysical Journal Letters.

-Reuters