Giant 'Pac-Man' Black Holes May Grow by Gobbling Other Black Holes

This visualization shows an accretion disk surrounding a supermassive black hole.
This visualization shows an accretion disk surrounding a supermassive black hole. (Image credit: Scott C. Noble)

Like the famous video game superhero Pac-Man, black holes may grow by gobbling up feasts — in their case, other black holes, a new study found.

Simulations suggest that this could happen in the zones just outside the gravitational influence of supermassive black holes, which reside in the hearts of galaxies. In these regions, gravity draws gas, stars, dust and even other black holes to the supermassive black hole.

Black holes drawn to the supermassive black hole get stuck in the disk of matter that surrounds it (known as an accretion disk). Over time, some of these smaller black holes collide, merge, and become bigger and stronger.

Related: Eureka! Scientists Photograph a Black Hole for the 1st Time

This scenario could help to explain a peculiar situation that astronomers observed recently when they detected a merger by measuring gravitational waves (ripples in space-time caused by large interactions in space, such as black holes coming together). Research teams around the world have so far identified 10 black hole mergers, but one of these mergers had unusual characteristics, with higher spin and mass measures than the others. It seemed to be outside the realm of scientists' current understanding.

The next step in understanding this strange merger, and potentially providing evidence that it resulted from a "Pac-Man" merger, would be to find more gravitational waves showcasing the signature of large, spinning black holes, the research team behind the study said in a statement.

"This could be a unique way of probing the physics around these supermassive black holes," Richard O'Shaughnessy, a team member participating in the new study and an astrophysicist at the Rochester Institute of Technology in New York, said in the statement. "It offers unique insight into how the centers of galaxies grow, which is of course essential to understanding how galaxies as a whole grow, which explains most of the structure in the universe."

This research was published on Nov. 1 in the journal Physical Research Letters.

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Elizabeth Howell
Staff Writer, Spaceflight

Elizabeth Howell (she/her), Ph.D., is a staff writer in the spaceflight channel since 2022 covering diversity, education and gaming as well. She was contributing writer for Space.com for 10 years before joining full-time. Elizabeth's reporting includes multiple exclusives with the White House and Office of the Vice-President of the United States, an exclusive conversation with aspiring space tourist (and NSYNC bassist) Lance Bass, speaking several times with the International Space Station, witnessing five human spaceflight launches on two continents, flying parabolic, working inside a spacesuit, and participating in a simulated Mars mission. Her latest book, "Why Am I Taller?", is co-written with astronaut Dave Williams. Elizabeth holds a Ph.D. and M.Sc. in Space Studies from the University of North Dakota, a Bachelor of Journalism from Canada's Carleton University and a Bachelor of History from Canada's Athabasca University. Elizabeth is also a post-secondary instructor in communications and science at several institutions since 2015; her experience includes developing and teaching an astronomy course at Canada's Algonquin College (with Indigenous content as well) to more than 1,000 students since 2020. Elizabeth first got interested in space after watching the movie Apollo 13 in 1996, and still wants to be an astronaut someday. Mastodon: https://qoto.org/@howellspace