A team of astronomers has managed to calculate the speed of a distant supermassive black hole’s spin thanks to the object’s chance meeting with a star—which it promptly destroyed. All black holes have spin, which they develop through their interactions with other matter in space. When black holes grow by accreting matter, they can spin to greater speeds; when they grow through mergers with other massive objects, they tend to slow down.
In its recent work, the team managed to deduce a supermassive black hole’s spin by measuring the wobble of its accretion disk after a star has been disrupted—a polite word for torn up—by the gigantic object. They found the black hole’s spin was less than 25% the speed of light—slow, at least for a black hole. The team’s research was today in Nature.
“The spin of a black hole is tied to its evolution. For example, a black hole that grew by steady accretion of gas over billions of years tends to be high spinning while a black hole that grew by mergers with other black holes should be slow spinning,” said Dheeraj Pasham, an astronomer at MIT and the lead author of the new paper, in an email to Gizmodo. are regions of spacetime with gravitational fields so intense that beyond a certain point, called an event horizon.
But black holes also pull plenty of material into their vicinity, which is brilliant, allowing researchers to study the physics of these shadowy behemoths. The material—an assemblage of rocky debris, dust, and g.
