Black holes have always fascinated us. They are mysterious objects with gravity so intense that even light can’t escape them. Their edges—called event horizons—are boundaries where space and time twist into the unknown. But just when we thought we had a handle on how big these cosmic giants could get, scientists discovered a black hole that broke all the rules.
This black hole, located in the centre of a galaxy called Phoenix A, is the largest one ever found. Nestled within the Phoenix Cluster, a massive group of galaxies 5.7 billion light-years away, this black hole—named Phoenix A*—has a staggering mass of 100 billion times that of our Sun.
How Big is Phoenix A*?
To understand the scale of Phoenix A*, it helps to compare it to other famous black holes.
For years, TON 618, a black hole in a hyper-bright quasar 10.4 billion light-years away, was the heavyweight champion. With a mass of 40.7 billion Suns, it was thought to represent the upper size limit for black holes. Similarly, M87*—the first black hole ever photographed in 2019—has a mass of several billion Suns and is already large enough to boggle the mind.
Phoenix A*, however, dwarfs them all. It’s so enormous that it could swallow our entire Solar System, including the Sun and all the planets, without a trace. In fact, scientists estimate its event horizon—the edge beyond which nothing can escape—might even exceed the orbit of Neptune.
As some of you correctly pointed out, the claim that TON 618 is the largest object in the Universe is now outdated.
Recent discoveries have identified Phoenix A, a supermassive black hole with an estimated mass of around 100 billion suns—or possibly even more, as its exact… pic.twitter.com/3TIL7iC8QO
— Black Hole (@konstructivizm) December 17, 2024
The Phoenix Cluster
Phoenix A* lies at the centre of the Phoenix Cluster, a galaxy cluster first discovered in 2010. This cluster isn’t just massive—it’s also one of the most energetic regions in the universe, emitting more X-rays than any other known cluster. Much of this energy likely comes from activity around the supermassive black hole at its heart.
Changing What We Know About Black Holes
Before this discovery, scientists believed black holes had a maximum size of about 50 billion solar masses. Phoenix A* has blown past that limit, forcing astronomers to rethink how black holes grow and evolve.
How did Phoenix A* get so massive? Black holes grow by consuming gas, dust, stars, and even other black holes. Over billions of years, Phoenix A* seems to have devoured enough material to double what was thought to be possible.
A Window into the Unknown
Phoenix A* doesn’t pose any threat to Earth—it’s too far away to affect us. But its discovery is a game-changer for science. It challenges our understanding of how black holes and galaxies form and raises new questions about the limits of these objects.
For now, Phoenix A* holds the title of the biggest black hole ever discovered. But as telescopes improve and scientists explore the universe further, who knows what other cosmic monsters we might find?
Phoenix A* is a reminder of how much there still is to learn about the vast and mysterious universe we call home.
