More than 100 black holes have been hiding in the Milky Way all this time

Imagine this, but more than 100 of them fall into a star cluster.

Of all the things you’ll find hidden in your cosmic backyard, you probably wouldn’t expect a black hole. Something of this magnitude and impact could be something remarkable, you think. I happen to be wrong, and not just a black hole we’ve since discovered.

A study, published in Nature on Monday, uncovers more than 100 stellar-mass black holes hidden within a star cluster moving through the Milky Way, and while that may sound scary in theory, there are more than meets the eye.

The cluster in question, Palomar 5, is about 80,000 light-years away from us, with the same stars 30,000 light-years away within the cluster, creating a stellar stream through the galaxy. But it is the black holes that have attracted attention.

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“The number of black holes is about three times greater than expected than the number of stars in the cluster, which means that more than 20 percent of the total mass of the cluster is made up of black holes,” said Marc Gillis, astrophysicist. from the University of Barcelona and lead author of the study.

“Each has a mass about 20 times the mass of the Sun, and they formed in supernova explosions late in the lives of massive stars, when the cluster was still very young.”

The discovery helps identify Palomar 5 as a tidal mass, rather than a spherical mass. The difference lies in the extent of the stars: globular clusters consist of stars that formed around the same time, while tidal groups are distinguished by a range of ages, freely distributed in a stream.

Not only could this discovery help explain how tidal currents form, it could also be helpful in reducing the approximate age and number of black holes within groups like Palomar 5.

What is a black hole?

Dark and mysterious monsters of the universe.

The team’s simulations showed that eventually, within a billion years or so, the cluster would begin to melt completely, but not before changing its composition to become more of a black hole than a star.

According to Fabio AntoniniD., An astrophysicist at Cardiff University, “The big unknown in this scenario is how many black holes are in clusters, which is difficult to restrict observation because we cannot see black holes. Our method gives us a way to know how many black holes there are in a star cluster by looking at the stars they spit out. “