Milky Way covered in 100 million black holes, study reports

While scientists have long known there are many holes throughout the reaches of the space, they did not expect to find as many as they did.
By Clint Huston | Aug 11, 2017
Astronomers at the University of California, Irvine have found evidence that our galaxy is likely home to tens of millions of black holes, new research published in the Monthly Notices of the Royal Astronomical Society reports.

While scientists have long known there are many holes throughout the reaches of the space, they did not expect to find as many as they did.

The team first started to research this new discovery after the Laser Interferometer Gravitational-Wave Observatory (LIGO) detected a series of gravitational waves generated by the collision between two massive black holes. Not only are such impacts rare, but the one looked at in the study also suggested an unexpected number of large black holes throughout the Milky Way.

"Fundamentally, the detection of gravitational waves was a huge deal, as it was a confirmation of a key prediction of Einstein's general theory of relativity," said James Bullock, a professor of physics & astronomy at the University of California, Irvine, in a statement. "But then we looked closer at the astrophysics of the actual result, a merger of two 30-solar-mass black holes. That was simply astounding and had us asking, 'How common are black holes of this size, and how often do they merge?'"

The team estimated the number of black holes by looking at the different sized stars found across the Milky Way. Our galaxyis the home to a lot of metal-rich bodies, which tend to shed a lot of mass over their lifetime and form smaller black holes. The team then took that information and used it to estimate the number ofaging stars that have died and turned into black holes.

"We have a pretty good understanding of the overall population of stars in the universe and their mass distribution as they're born, so we can tell how many black holes should have formed with 100 solar masses versus 10 solar masses," explained Bullock, according to UPI. "We were able to work out how many big black holes should exist, and it ended up being in the millions -- many more than I anticipated."

This new finding gives researchers a better idea of the universe and suggests that more massive black hole mergers will be detected in the years ahead. In fact, they expect that 50-solar-mass black holes will be detected within the next few years. By studying such events they will likely gain even more insight into the mechanisms that drive our galaxy.


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