Black holes are some of the most mysterious objects out there in space but what is more fascinating is how many they are. With many of them being found at far away galaxies, it was interesting to have found over 100 of them in the Milky way Galaxy.
Black holes are massive and would usually have a great effect on other celestial objects around them but how come scientists could miss so many of them despite all being in the milky way galaxy to start with.
The new study published in the journal Nature on Monday showed the presence of over 100 stellar-mass black holes which are hidden within a cluster of starts that are moving across the Milky Way.
The cluster of stars called the Palomar 5 is about 80,000 light-years away from Earth and the stars are spaced up to 30,000 light-years away from each other within the cluster which in effect creates a stellar stream across the galaxy and then the black holes caught the attention of scientists.
Astrophysicist Mark Gieles from the University of Barcelona as well as the lead author of the study made it known that “The number of black holes is roughly three times larger than expected from the number of stars in the cluster, and it means that more than 20 percent of the total cluster mass is made up of black holes.”
“They each have a mass of about 20 times the mass of the Sun and they formed in supernova explosions at the end of the lives of massive stars, when the cluster was still very young.”
The discovery helps identify Palomar 5 as a tidal cluster, not a globular cluster. The difference lies within the spread of stars — globular clusters consist of stars all formed around the same time, while tidal clusters feature an array of ages, loosely distributed in a stream.
Before now, the origins of tidal streams had only been hypothesized. Now, with further analysis of Palomar 5 — a unique case — Gieles’ team was able to use N-body simulations to recreate the orbits and evolutions of the stars making up the cluster.
According to the scientists, they deduced that the cluster’s tidal stream could have been formed as a result of a significant number of black holes which has caused dramatic effects on the behaviors of these stars within the cluster.
Not only could this discovery help explain how these tidal streams form, but it also may be instrumental in narrowing down the rough age and amount of black holes within clusters like Palomar 5.
The team was able to create a simulation which showed that in about a billion years, the cluster will begin to dissolve completely but not before its composition changes to be more black hole than star.
According to Fabio Antonini, an astrophysicist from Cardiff University, “A big unknown in this scenario is how many black holes there are in clusters, which is hard to constrain observationally because we can not see black holes. Our method gives us a way to learn how many black holes there are in a star cluster by looking at the stars they eject.”
The new discovery showed that there are in fact more mysteries out there in the interstellar space but they are just too far away from us to quickly take notice of them even though more scientific researches will continue to be carried out and hopefully we discover more fascinating things about the universe.