Astronomers have discovered three actively feeding supermassive black holes in a single galaxy more than 12.5 billion light-years from Earth. The finding, made by an international research team led by the Max Planck Institute for Extraterrestrial Physics (MPE), offers a rare glimpse of how enormous black holes grew and interacted during the universe's earliest stages.

The black holes are located in a galaxy known as J0148-4214. All three are actively accumulating matter, which spirals toward them through surrounding disks of gas and other material. Because the galaxy is so distant, its light has traveled through space for approximately 12.5 billion years before reaching Earth. This means astronomers are observing it as it existed just 1.2 billion years after the Big Bang.

Over such vast distances, the expansion of the universe stretches light to longer, redder wavelengths. Astronomers measure this effect through a property called redshift.…