A colossal black hole, located in a galaxy five billion light years away, boasts a mass over 10,000 times greater than the ultra-massive black hole found at the center of the Milky Way, and about 360 times greater than that of our Sun.

“This is likely the largest black hole in the universe,” states Thomas Collett from the University of Portsmouth, UK. “It’s equivalent to the mass of an entire small galaxy condensed into one singularity.”

This supermassive black hole is situated approximately five billion light years away, residing in one of the most well-known galaxies, referred to as the Space Horseshoe. Space Horseshoes serve as the largest known galaxy lenses, capable of bending light from objects situated behind them due to their immense gravitational forces. Previous research indicated that such enormous black holes might exist in the center of this galaxy, though pinpointing their exact mass has proven challenging for scientists.

To accurately determine the mass of the black hole, Collett and his team analyzed the orbital velocity of a nearby star, which directly correlates to the black hole’s mass. Additionally, they assessed how much light is distorted by the gravitational influence of the black hole, a phenomenon known as gravitational lensing. “Combining these two measurements allowed us to yield a highly confident estimation,” says Collett.

The mass of this black hole is remarkably large, aligning with Collett’s team’s prior investigations. Their research focuses on mapping the distribution of dark matter in the Galaxy, utilizing data gathered from observed light. They found that a successful model was only achievable with the inclusion of a supermassive black hole at the center of the universe’s horseshoe.

“The only time I started to get a good model was when I began considering black holes with incredibly high masses,” remarks Collett.

The horseshoe galaxy is theorized to be a ‘fossil group’ galaxy. This type of stellar system has absorbed all of its neighboring galaxies, a behavior that helps clarify the phenomenon of its black hole’s formidable size.

Yet, one enigmatic aspect persists. The black hole appears to have ceased growing and is currently dormant. “For it to expand, it must have been connected to the entire universe at some stage. It’s curious that it’s inactive at this moment,” Collett adds. “A process must have contributed to the black hole’s growth before it eventually plateaued.”