Astronomers have discovered the closest massive black hole to Earth. This black hole, located in the star cluster Omega Centauri, is about 18,000 light-years away and boasts a mass of approximately 8,200 suns. What makes this finding particularly fascinating is that the black hole seems to be "frozen in time."

Anil Seth, the lead researcher from the University of Utah, explained the discovery as a "once-in-a-career kind of finding." He added, “This is really, truly extraordinary evidence. I’ve been excited about it for nine straight months. Every time I think about it, I have a hard time sleeping."

Introduction to Intermediate-Mass Black Holes

This black hole is classified as an "intermediate-mass black hole," a rare type that bridges the gap between smaller stellar-mass black holes and the enormous supermassive black holes. Stellar-mass black holes, formed by the collapse of large stars, are a few times the mass of our sun. In contrast, supermassive black holes, found at the centers of galaxies, can have millions or billions of solar masses.

Black Hole to Earth
Image Source:
The University of Utah

Matthew Whittaker, an undergraduate student, and co-author from the University of Utah, described, "There are black holes a little heavier than our sun that are like ants or spiders, they’re hard to spot, but kind of everywhere throughout the universe. Then you've got supermassive black holes that are like Godzilla in the centres of galaxies tearing things up, and we can see them easily."

Intermediate-mass black holes are evasive because they are usually not found at the centers of galaxies. Whittaker likened finding one to spotting Bigfoot, stating, "These intermediate-mass black holes are kind of on the level of Bigfoot. Spotting them is like finding the first evidence for Bigfoot—people are going to freak out."

Discovery in Omega Centauri

The researchers detected this black hole by observing the unusual movement of seven stars in Omega Centauri. These stars' motions suggested the presence of a massive object with a strong gravitational pull. This discovery, documented over two decades of Hubble Space Telescope observations, provides compelling evidence for the existence of intermediate-mass black holes.

Maximilian Haberle from the Max Planck Institute for Astronomy in Germany, the lead author of the study published in Nature, mentioned, "There has been a long debate whether intermediate-mass black holes exist in general, and specifically in Omega Centauri, and our detection might help to resolve that debate."

Omega Centauri, a cluster with about 10 million stars, is believed to be the core remnant of a small galaxy that the Milky Way absorbed 8 to 10 billion years ago. During this merger, the smaller galaxy's central black hole, which could have grown into a supermassive black hole, was left "frozen in time" due to the loss of its gas and growth interruption.

You might also be interested in - Indian scientists find rare three supermassive Black Holes merging in far-off Cosmos