Besides supermassive black hole The Milky Way, at the center of our galaxy, also serves as home to smaller stellar black holes formed during the collapse of a massive star. Scientists believe there is A black hole with 100 million stars only in our galaxy, but most of them have yet to be discovered. Those already found are, on average, about 10 times larger than our Sun, with the largest reaching 21 solar masses. according to data collected by European Space Agency’s Gaia mission, however, scientists discovered a stellar black hole 33 times the size of our sun, making it the largest black hole we’ve ever seen in our galaxy. It is also relatively close to our planet, about 1,926 light-years away.
Gaia BH3, as it is now called, was first spotted by a team of ESA scientists who were sifting through the mission’s data to look for anything unusual. An old giant star from the nearby constellation Aquila wobbled to their attention and discovered that it was orbiting a supermassive black hole. BH3 has been difficult to find despite being so close – it is now the second-closest black hole known to our planet – because it lacks celestial bodies close enough to feed matter and illuminate it in X-ray telescopes. Before the discovery, we had only found comparable black holes in distant galaxies.
The ESA team used data from ground-based telescopes European Southern Observatory to confirm the size of the newly discovered celestial body. They published a paper with their preliminary findings before releasing a more detailed paper in 2025 so that their peers can begin studying Gaia BH3. All they know so far is that the star orbiting it contains very few elements heavier than hydrogen and helium, and since the star pairs have similar compositions, the star that collapsed to form BH3 could have been the same.
Scientists have long believed that it is metal-poor stars that can form high-mass black holes after collapsing because they lose less mass during their lifetimes. In other words, theoretically they would still have plenty of material left to create a supermassive black hole by the time they die. This appears to be the first evidence we’ve found linking metal-poor stars to massive stellar black holes, and it’s also evidence that older giant stars evolved differently than the newer stars we see in our galaxy.
We are likely to see more detailed studies of binary systems and stellar black holes using data from BH3 and its companion star in the future. ESA believes that the discovery of BH3 is just the beginning and will be the focus of much more research as we try to unlock the mysteries of the universe.
