Sagittarius A* (pronounced Sagittarius A Star), the supermassive black hole at the center of the Milky Way, is spinning in an unusual way, and scientists now think they may know why. Based on new data from the Event Horizon Telescope, scientists suggest that the cosmic giant likely merged with another black hole billions of years ago. This colossal collision could explain the black hole’s rapid, erratic spin, which differs from the rest of the galaxy.
The Role of Fusion in the Evolution of Black Holes
Located 26,000 light-years from Earth, Sagittarius A* is a massive object, 4 million times the mass of the Sun. Its rapid spin and strange tilt have long puzzled astronomers, but new research suggests a turbulent past.
According to a study published in the journal Nature led by Yihan Wang, an astrophysicist at the University of Nevada, Las Vegas (UNLV), the black hole’s strange spin is best explained by a merger with another supermassive black hole. This event may have occurred about 9 billion years ago and could have drastically changed the spin of Sagittarius A*.
Supermassive black holes are thought to grow not only by swallowing nearby gas and dust, but also by merging with other black holes when galaxies collide. Bing Zhang, a professor of physics and astronomy at UNLV and a co-author of the study, explained that the merger likely occurred after the Milky Way collided with the galaxy Gaia-Enceladus. This adds significant evidence to the theory that black holes can expand by merging with other black holes.
Future discoveries await
Astronomers hope that future space projects, such as the Laser Interferometer Space Antenna (LISA), scheduled for launch in 2035, will help reveal more about the history of supermassive black holes. These tools will detect the gravitational waves produced by such mergers, providing even more insight into the dynamic evolution of galaxies and their black holes.
