A Group of Dark Cosmic Phenomena, Known as Black Holes, Wander Throughout the Milky Way Galaxy
In the vast expanse of the Milky Way, a remarkable discovery has been made. The Palomar 5 globular cluster, located approximately 65,000 to 80,000 light-years from Earth, has been found to contain over 124 black holes, three times more than previously thought.
This sparsely populated and ancient cluster, estimated to be around 11.5 billion years old, is one of the oldest in our galaxy. The recent studies, led by astrophysicists Michael Fellhauer, Kathryn V. Johnston, and their team, have shed new light on the intricate origins of tidal streams in clusters like Palomar 5, using data from the Gaia space observatory.
Each of these black holes in Palomar 5 weighs about 20 times that of our Sun. Together, they make up over 20% of the cluster's mass. The gravitational interactions with these black holes may explain the current arrangement of stars within Palomar 5.
Despite their impressive numbers, Earth is not in immediate danger from these black holes. The vast distances involved mean that the closest known black hole is still far enough away that it does not pose a threat to our planet.
The Milky Way is expected to be home to between 100 million to 400 million stellar black holes. Palomar 5, with its abundance of these cosmic giants, offers a unique opportunity to study the effects of black holes on star clusters over time.
Over billions of years, interactions between stars and black holes can lead to changes in orbits, but such events are rare and typically occur over very long timescales. It is believed that Palomar 5 will dissolve in about 1 billion years.
Interestingly, Palomar 5 is the only known instance where a tidal stream is linked to a stellar system. This discovery has opened up new avenues for understanding the dynamics of star clusters and their interactions with black holes.
At the centre of our Milky Way lies the supermassive black hole Sagittarius A*, with a mass of about 4.1 million times that of the Sun. Located approximately 26,000 light-years from Earth, it serves as a stark contrast to the smaller black holes found in Palomar 5.
The ongoing research into Palomar 5 promises to deepen our understanding of the Milky Way and the role of black holes in shaping the cosmos. As we continue to explore and learn, the mysteries of the universe remain as captivating as ever.
