Astronomers discover small black hole tip-toeing outside the Milky Way in new style

In a startling new discovery, astronomers have found a small black hole in a cluster of stars just outside our Milky Way galaxy. The black hole was tracked in the darkness of space using the European Southern Observatory’s (ESO) Very Large Telescope (VLT) based in Chile, according to ESO’s official statement. The detection was made possible by looking at how the black hole influences the motion of a star in its close vicinity.

Finding the hidden black hole

Interestingly, it is the first time that this detection method has been used to reveal the presence of a black hole outside of our galaxy.

Sara Saracino, the lead researcher and member of the Astrophysics Research Institute of Liverpool John Moores University said, ''Similar to Sherlock Holmes tracking down a criminal gang from their missteps, we are looking at every single star in this cluster with a magnifying glass in one hand trying to find some evidence for the presence of black holes but without seeing them directly. The result shown here represents just one of the wanted criminals, but when you have found one, you are well on your way to discovering many others, in different clusters.”

Detecting black holes directly using a telescope is extremely difficult as these behemoths are something that does not allow even light to escape. So to overcome this problem, the astronomers observed each star in the cluster around the potential location of the black hole. The “smoking gun”, as the experts call it, was its gravitational influence on the five-solar-mass star orbiting it. Experts found that this particular black hole was roughly 11 times as massive as our Sun and was lurking in NGC 1850, a cluster of thousands of stars roughly 1,60,000 light-years away in the Large Magellanic Cloud, a neighbouring galaxy of the Milky Way.

The statement revealed that this black hole has been found in a cluster of stars that is only 100 million years old, which is quite young in terms of astronomical scales. It further said that usage of the same method in other star clusters could unveil even more young black holes and shed new light on how they evolve. “By comparing them with larger, more mature black holes in older clusters, astronomers would be able to understand how these objects grow by feeding on stars or merging with other black holes. Furthermore, charting the demographics of black holes in star clusters improves our understanding of the origin of gravitational-wave sources,” the statement added.

Image: Twitter/@ESO