Black holes could be wandering at the edges of the Milky Way

8/29/2021- 9:00 p.m.

According to the study researchers, because the number of black holes increases the more mass there is in the outer “halo” of material that surrounds galaxies, clusters of galaxies, which have heavy halos, could have even more of the ravenous wanderers.

There could be 12 of the invisible giants in the Milky Way alone.

An enormous number of rogue supermassive black holes may be wandering around the universe, new simulations find.

In fact, wandering giant black holes may account for a whopping 10% of the nearby universe’s black hole mass “‘budget,'” the research finds. This means that galaxies like our own could have an average of 12 invisible behemoths prowling around their outskirts, gobbling up anything that gets in their way.

Just as a panama basket can be woven around the supporting structure of a stone, astronomers think that most galaxies form around supermassive black holes. The gigantic gravitational beasts, often many millions or even billions times more massive than the sun, act as anchors for long trains of gas, dust, stars and planets that swirl in orbit around them. 

Closer to the black holes, this material spirals faster and heats up, forming an accretion disk that both feeds the black hole and produces the telltale radiation that makes it visible. 

The simulations predicted that the frequent galactic collisions of the early universe, between the time of the Big Bang about 13.7 billion years ago and roughly 2 billion years later, produced enough wanderers to outnumber, and even outshine, their galactically fixed supermassive black hole cousins. 

The researchers “next steps will be to figure out possible hallmarks of the lost invisible giants'” presence out in the universe so that one day soon, we can observe them first hand.

“As a result, Milky Way-mass galaxies in Romulus are found to host an average of 12 supermassive black holes, which typically wander the halo far from the galactic center.”