100 Stellar Black Holes Found Hidden in Fluffy Star Cluster 80,000 Light-Years Away from Solar System

In the heart of a fluffy star cluster, unsuspecting of anything hidden, 100 stellar-mass black holes have been discovered by researchers. If validated, the sighting will shed light on how clusters came to be the way they are, where their stars are spaced light-years away from each other, smearing out into a stellar stream that can stretch across roughly 30,000 light-years.

What are Black Holes?

Stellar-mass black holes are a type of black hole that's formed from the gravitational collapse of a star. These often have masses that range from roughly 5 to tens of solar masses. According to National Geographic, are points in space where density created deep gravitational sinks. Beyond this, not even light can escape the overpowering tug of a black hole's gravity.

Any object, whether a star, planet, or spacecraft that veers too close to a black hole, will be stretch and compressed, theoretically.

There are 4 types of black holes: intermediate, supermassive, miniature, and stellar. Stellar death is the most commonly known type of black hole. As the star reaches the end of its life, it will inflate, lose mass, and cool into a white dwarf star. On the other hand, some that are at least 10-20 times our star's size are destined to become stellar-mass black holes or super-dense neutron stars.

Discovery of 100 Stellar-Mass Black Holes

The fluffy star cluster, Palomar 5, is roughly 80,000 light-years away from our solar system. The globular clusters such as these are often considered to be remnants of the early Universe. They are often dense and spherical, containing, typically, about 100,000 to a million old stars, with some as old as the known Universe itself.

All globular clusters have stars formed simultaneously, mostly from the same cloud of dust and gas. On the other hand, there are other star groups that are recently gaining more attention, tidal streams that stretch across the sky. Previously, these have been nearly impossible to identify; however, with the help of the Gaia space observatory working on mapping the Milky Way with the utmost precision in 3D, more of the streams are being discovered, reports ScienceAlert.

Mark Gieles, the lead author and astrophysicist from the University of Barcelona, explains that as of now, how the streams form is unknown. One thing is for certain; these streams are disrupted star clusters.

The study published in the journal Nature Astronomy, entitled "A supra-massive population of stellar-mass black holes in the globular cluster Palomar 5," was discovered when the team of researchers used detailed N-body simulations to understand the orbit and evolutions of the star clusters.

Recent evidence suggests that black hole populations could exist within the central regions of the globular clusters since their gravitational interactions could send stars veering away. Gieles explains that the number of black holes was about three times more than expected based on the number of stars within the cluster. This means that roughly 20% of the net cluster mass consisted of black holes.