The black hole is a topic that has gained interest around the world for years. Scientists believe that a detailed study of black holes could help in understanding the evolution of the universe. Astronomers have now claimed to make an unexpected finding. They have discovered a concentration of smaller black holes rather than one massive black hole. The concentration is lying hidden at the center of NGC 6397 which is a globular cluster. It is among the two globular clusters that are close to Earth. It is located at a distance of 7,800 light-years from Earth. Globular clusters are stellar systems. They host stars. These starts are closely packed with each other. In other words, such clusters are extremely dense.
NGC 6397 which was at the focus of the study is said to be very old. Astronomers believe that its age is almost similar to that of the universe. It is also called a core-collapsed cluster. Astronomers earlier thought that NGC 6397 was home to an intermediate-mass black hole. These are the missing link between supermassive black holes and stellar-mass black holes. The supermassive black holes are predicted to be millions of times of Sun’s total mass. They lie at the cores of galaxies. Their existence is still a hotly debated topic in the world because astronomers have so far managed to identify only a few candidates.
Astronomers said that they were surprised to found a shred of strong evidence for an invisible mass at the core of NGC 6397. They said that this extra mass is not point-like. It is only extended to a few percent of the cluster’s size. Astronomers also decided to determine the distribution of the cluster’s total mass. They used velocities of stars for the purpose. Astronomers said that stars travel faster in some areas having more mass. Astronomers used the Hubble Space Telescope for years to make observations. The data collected were then added to well-calibrated proper motion measurements by the Gaia space observatory of the ESA. This is the first study that provides both the mass and what appears to be a collection of black holes in NGC 6397.