A wayward supermassive black hole hiding 600 million light-years from Earth has made its presence known in a spectacular cosmic spectacle — by consuming a star and producing a dazzling flash of light.

Astronomers utilizing NASA’s Hubble Space Telescope, along with various other observatories, observed the flare from this obscured black hole, which is located far from the core of its galaxy — around 2,600 light-years off its expected path. This is noteworthy, as the majority of supermassive black holes are situated at the hearts of their galaxies.

Even more fascinating, the galaxy already contains a central supermassive black hole with a mass 100 million times that of our sun. The newly identified “roaming” black hole is smaller, with a mass comparable to that of 1 million suns.

The flare, referred to as a tidal disruption event (TDE), took place when a star ventured too near the rogue black hole and was ripped apart by its colossal gravitational pull. The ensuing flash of radiation was the sole indication of the black hole’s presence.

“This paves the way for the potential discovery of a concealed population of wandering black holes in future sky surveys,” stated Yuhan Yao, a researcher at UC Berkeley and principal author of the study. “I believe this finding will encourage scientists to seek out more of these occurrences.”

Among approximately 100 TDEs identified to date, this one — designated AT2024tvd — marks the first associated with a supermassive black hole outside a galactic core. NASA has announced these findings, which will be detailed in The Astrophysical Journal Letters.

Black holes, once deemed mere theoretical curiosities, are now recognized as well-established cosmic phenomena. In contrast to stars or planets, black holes lack a solid surface. Instead, they feature an “event horizon” — a boundary beyond which nothing, not even light, can escape.

Stellar black holes, the most prevalent type, form when immense stars collapse after supernova detonations. Supermassive black holes, however, remain more enigmatic. Researchers suspect they are present in the centers of nearly all galaxies, possibly forming in the densely populated, star-producing areas known as starburst galaxies.

In this instance, as the fated star was torn apart, some of its gas created a luminous disk around the black hole, emitting powerful ultraviolet and visible light. Ground-based telescopes, such as the Zwicky Transient Facility in California, were the first to detect the flare. Hubble subsequently verified its off-center position. Additional information was provided by NASA’s Chandra X-ray Observatory and the Very Large Array in New Mexico.

Despite being within the same galaxy, the two supermassive black holes are not gravitationally linked as a binary system. The reason the smaller one ended up so distant from the galactic center is still unclear.

One hypothesis proposes that it emerged from a smaller galaxy that colluded with the larger one, transporting its central black hole along. Over time, the rogue black hole may spiral inward and ultimately merge with the larger one. Another theory involves a three-body interaction, where gravitational influences from two larger black holes ejected the smaller one from the nucleus.

“Theorists have long theorized that massive black holes could exist away from galactic centers,” remarked Ryan Chornock, a member of the ZTF team. “Now, we can utilize TDEs to locate them.”

This revelation not only illuminates the concealed dynamics of galaxies but also opens up a new perspective into the elusive realm of wandering black holes.