The UC Berkeley research team, led by graduate student Casey Lam and associate professor of astronomy Jessica Lou, may have discovered the first “free-floating” black hole, Science Daily reports.
According to the outlet, they estimate that this invisible object, OB110462, is 1.6 to 4.4 times the mass of the Sun and 2,280 to 6,260 light-years away. For now, researchers say it could also be a neutron star, a “city-sized” star that is born in large numbers, collapsing and dying. Whether it’s a black hole or a neutron star, Science Daily reports that the mysterious object is the first “stellar” ghost “to float in space without an accompanying star.
“This is the first free-floating black hole or neutron star to be discovered with gravitational microlensing,” Lu told the outlet. Lu has been hunting free-floating black holes since 2008 and has been monitoring OB110462 since 2020. “With the help of microlensing, we can examine and weigh these solitary, compact objects. I think we have opened a new window on this. Dark objects, which cannot be seen in any other way.” Although black holes are generally invisible, researchers can use gravitational microlensing to see how they divert and distort light from distant stars with their powerful gravitational field.
According to UC Berkeley’s astronomy department, black holes are “one of the most extraordinary phenomena in astrophysics.” Their website states that the galaxy contains approximately 100 million stellar-black holes, and the Science Daily reports that the UC Berkeley team estimates that there are now 200 million black holes. The outlet says that determining how many are in total will help astronomers better understand how stars die – shedding more light on the evolution of our galaxy.
For now, Luche’s team says OB110462 is a black hole that could not determine the neutron star, but they hope to collect more data from NASA’s Hubble Space Telescope and then perform more detailed analyzes.
“We want to say that this is definitely a black hole. We should report all permitted measures,” Lune told Science Daily. “This includes both lower mass black holes and possibly neutron stars.”