Using data from Caltech’s Palomar Observatory, astronomers have spotted a black hole moving through space and consuming a star 600 million lightyears away.
It was found via observations of a tidal disruption event called AT2024tvd.
More black hole science
Tidal disruption events occur when a star approaches a supermassive black hole and gets violently ripped apart, causing outflows of radiation that can be detected by astronomers.
Most supermassive black holes lie at the centres of their galaxies, but AT2024tvd was found strangely off to one side of its galactic centre.
"AT2024tvd is the first offset tidal disruption event captured by optical sky surveys, and it opens up the entire possibility of uncovering this elusive population of wandering black holes with future sky surveys," says Yuhan Yao, lead author of the study investigating AT2024tvd.
A second, larger supermassive black hole sits at the centre of AT2024tvd’s galaxy.
The two are about 2,600 lightyears apart, just a 10th of the distance between our Sun and Sagittarius A*, the Milky Way’s central supermassive black hole.
But despite their proximity, the duo are not gravitationally bound to one another.
A cosmic conundrum
Scientists remain puzzled as to how this wandering giant ended up so offset.
One theory is that an interaction between three black holes might have resulted in it being ejected from the galactic centre.
"If the black hole went through a triple interaction with two other black holes in the galaxy’s core, it can still remain bound to the galaxy, orbiting around the central region," continues Yao.
Others think it’s more likely due to a galactic merger.
Erica Hammerstein, another author of the study, explains: "There is already good evidence that galaxy mergers enhance tidal disruption event rates.
"But the presence of a second black hole in AT2024tvd’s host galaxy means that at some point in this galaxy’s past, a merger must have happened.”
This story appeared in the July 2025 issue of BBC Sky at Night Magazine
