Astronomers Spot Giant Black Holes Spiraling Towards A Cosmic Collision

by Aaron Leong — Thursday, April 09, 2026, 11:00 AM EDT

Deep in the heart of the galaxy Markarian 501 some 460 million light-years away, scientists have found two supermassive black holes locked in a gravitational dance that could end in a final, violent collision.

Astronomers have long struggled to explain how supermassive black holes reach masses millions or even billions of times that of the Sun. While black holes do grow by devouring gas and dust, the sheer growth of these behemoths within their evolutionary time doesn't add up mathematically. Thus, it's been proposed that supermassives is what happens when two smaller black holes love each other very much.

Now, a team led by Silke Britzen of the Max Planck Institute for Radio Astronomy may have found the most compelling evidence yet of a pair on the brink of making that life commitment together. By analyzing 23 years of radio frequency data, researchers discovered that the galaxy’s central engine is actually firing two distinct jets of supercharged particles instead of one. These jets, traveling at nearly the speed of light, are beacons for the invisible monsters driving them.

black hole hz — *Graphical depiction showing the central region of the galaxy Mrk 501 at a frequency of 43 gigahertz on three different days. (Credit: S. Britzen)*

The discovery was made possible by the peculiar orientation of Mrk 501. As a blazar, one of its jets is pointed almost directly at Earth. However, the data revealed a second, fainter jet moving in a counterclockwise loop around the radio core. "Evaluating the data felt like being on a ship," Britzen noted, describing how the entire jet system appears to sway. This wobble is a telltale sign of two massive objects orbiting one another, their mutual gravity causing the orbital plane to precess like a spinning top.

In an observation in June 2022, the alignment of the two black holes were JUST right that it caused light from the rear jet to be bent by the gravity of the front black hole, forming a so-called Einstein ring.

The two giants are estimated to orbit each other every 121 days. While they are separated by a distance several hundred times the gap between Earth and the Sun, on a galactic scale, they are practically touching. They have already cleared out most of the stars and gas in their immediate neighborhood, a stage of orbital decay that usually stalls for billions of years.

Current models suggest the pair could collide in a mere 100 years. As the union becomes inevitable, the pair is expected to release a rhythmic hum of low-frequency gravitational waves, which scientists are already planning to track with pulsar timing arrays (PTAs).

Main image credit: Emma Kun / HUN-REN Konkoly Observatory / Made with the support of AI