Scientists from the European Space Agency’s Gaia mission have discovered the largest stellar-origin black hole in our galaxy, Gaia BH3. Located just 1,926 light-years from Earth in the constellation Aquila, this black hole, with a mass 33 times that of the sun, is the largest of its kind discovered to date. It is significantly more massive than Cygnus X-1, which had been the previous Milky Way record-holder.
Gaia BH3 is part of a binary star system and has a symbiotic orbit with a “subgiant” star about five times the size of our sun. The newly discovered black hole is classified as “dormant” as it does not appear to be actively attracting nearby stars or dust. That feature makes dormant black holes much more difficult to detect through conventional astronomical methods.
Record breaker! Milky Way's most monstrous stellar-mass black hole is sleeping giant lurking close to Earth https://t.co/zgUP56O0GD pic.twitter.com/rKj3mIkpST
— SPACE.com (@SPACEdotcom) April 16, 2024
Lead researcher Pasquale Panuzzo from the Observatoire de Paris expressed his astonishment at the discovery, stating, “No one was expecting to find a high-mass black hole lurking nearby, undetected so far. This is the kind of discovery you make once in your research life.”
The discovery was made possible by Gaia’s unprecedented precision in detecting previously unobservable movements by stars in the Milky Way. Ultimately, Gaia intends to produce a comprehensive model of over a billion stars in our galaxy that will track their motions, luminosity and composition.
“Finding Gaia BH3 is like the moment in the film ‘The Matrix’ where Neo starts to ‘see’ the matrix. In our case, ‘the matrix’ is our galaxy’s population of dormant stellar black holes, which were hidden from us before Gaia detected them,” said George Seabroke, a scientist at the Mullard Space Science Laboratory.
Interestingly, the chemical composition of the companion star mirrors found in old metal-poor stars within the galaxy supports theories that more massive black holes can form from metal-poor stars. The findings from Gaia BH3 could lead to more groundbreaking discoveries in several branches of astronomy. Further development of the technology used to detect and observe dormant black holes could refine approaches to exploring many other celestial phenomena. Improvements in methodology are likely to enhance our capability to predict and study cosmic events that could directly affect our solar system.
