Astronomers have uncovered a previously unknown supermassive black hole in the Large Magellanic Cloud (LMC), one of the Milky Way’s closest galactic neighbors. This groundbreaking discovery, made using data from the European Space Agency’s Gaia mission, reveals a 600,000-solar-mass black hole that has been hiding in plain sight—ejecting stars at millions of miles per hour into intergalactic space. This new finding, detailed in a study recently published on arXiv, sheds light on the complex dynamics of runaway stars.
Black holes are notoriously elusive, emitting no light of their own, making them difficult to detect. However, this black hole revealed itself through the violent ejection of hypervelocity stars—runaway stars traveling so fast that they will never return to the Milky Way. According to researchers at the Harvard-Smithsonian Center for Astrophysics, about half of these stars originate from our own galaxy’s central black hole, Sagittarius A*. But the other half comes from somewhere entirely unexpected—leading scientists to an astonishing revelation.
The forensic trail of hypervelocity stars
Just as forensic experts trace a bullet’s trajectory to determine its origin, astronomers can analyze the paths of stars to uncover their source. In this case, scientists studied 21 hypervelocity stars at the edge of the Milky Way and found a pattern they couldn’t explain—until they turned their attention to the LMC.
“It is astounding to realize that we have another supermassive black hole just down the block, cosmically speaking,” said Jesse Han, lead author of the study. “Black holes are so stealthy that this one has been practically under our noses this whole time.”
These runaway stars were moving at extreme speeds, some exceeding a million miles per hour—far too fast for the Milky Way to have launched them all. By modeling the orbits of these stars, researchers found that many had been ejected from the Large Magellanic Cloud’s center, a location that had no previously known black hole.
How a black hole turns stars into cosmic slingshots
The discovery of the LMC black hole is linked to a dramatic phenomenon: the ejection of hypervelocity stars. These stars originate from binary systems—pairs of stars that orbit each other. When such a system gets too close to a supermassive black hole, the intense gravitational forces rip it apart. One star is captured into orbit around the black hole, while the other is slingshotted away at mind-boggling speeds.
“Hypervelocity stars are created when a double-star system ventures too close to a supermassive black hole,” explained Kareem El-Badry, co-author of the study. “The intense gravitational pull from the black hole rips the two stars apart, capturing one and flinging the other out of the galaxy.”
Scientists have long suspected that the LMC could harbor a hidden black hole, but no direct evidence had ever been found—until now. The team’s theoretical models predicted that a black hole in the LMC would create a specific pattern of hypervelocity stars, concentrated in one section of the Milky Way. The new data aligned perfectly with that prediction.
A monster lurking in the Large Magellanic Cloud
While the LMC’s black hole is far smaller than Sagittarius A* (which has a mass of about 4 million Suns), it still ranks as a supermassive black hole—an extremely rare find outside of large galaxies. With a mass of approximately 600,000 Suns, it dwarfs stellar-mass black holes but remains modest compared to the billion-solar-mass behemoths found in some distant galaxies.
“The only explanation we can come up with for this data is the existence of a monster black hole in our galaxy next door,” said Scott Lucchini, another co-author of the study.
This discovery not only reveals the first confirmed supermassive black hole in the LMC, but also expands our understanding of how galaxies interact. The LMC is currently on a collision course with the Milky Way, and in a few billion years, it will merge with our galaxy, potentially feeding our central black hole with fresh material.
