Astronomers Confirm First Solitary Black Hole near Milky Way

Astronomers have confirmed the first-ever observation of a solitary, or 'lone,' stellar-mass black hole drifting through the Milky Way, located in the constellation Sagittarius and estimated at about seven times the mass of the Sun. This discovery was made possible by gravitational microlensing, where the black hole's gravity bent and magnified the light from a background star as it passed in front, revealing its presence despite having no companion star. Initially spotted using Hubble Space Telescope data between 2011 and 2017, the object's nature was debated, with some suggesting it might be a neutron star, but subsequent observations—including those from the Gaia probe—confirmed it as a black hole. The agreement between previously conflicting research groups has settled the object's identity, and this detection opens the door to finding more of these elusive wanderers, which were previously only theorized due to the difficulty of detecting black holes without companion stars. Estimates suggest there could be up to 100 million such hidden black holes in our galaxy, but their discovery relies on rare alignments that produce detectable lensing events. The confirmed discovery is significant for understanding black hole populations and the dynamics within the Milky Way.