Two supermassive black holes may collide 100 years from now ‪ — ‬ and Earth would feel it

Kenna Hughes-Castleberry
Live Science
Thu, 16 Apr 2026 15:04 UTC

© Mark Garlick/Science Photo Library via Getty Images

An illustration showing two black holes beginning to collide.

In a galaxy 500 million light-years away, two supermassive black holes could merge, spreading gravitational waves across the universe.

Astronomers may have discovered an extreme pair of light-spewing black holes that are spiraling toward an enormous collision — the effects of which could be felt in the next century.

Using decades of radio telescope observations, the astronomers studied an ultrabright object that was previously thought to be a blazar — a glowing core of a galaxy usually powered by a black hole — some 500 million light-years from our solar system. The observations revealed a hidden jet of energy that suggests the intensely bright object is actually two black holes on the verge of colliding, perhaps less than 100 years from now.

"We expect one (merged) black hole to remain," study co-author Silke Britzen, an astronomer at the Max-Planck Institute for Radio Astronomy, told BBC Science Focus. "I am really curious to observe how this 'dance' will continue."

The findings were published March 27 in the journal Monthly Notices of the Royal Astronomical Society.

Finding two black holes

Blazars are some of the most luminous objects in the universe. They're classified as active galactic nuclei — actively feeding objects at the centers of galaxies, usually powered by supermassive black holes — and typically shoot jets of high-energy radiation toward Earth. Usually, a central black hole is the source for this jet, but in the case of the blazar in the galaxy Markarian 501, something didn't quite add up.

© Emma Kun / HUN-REN Konkoly Observatory

The supermassive black hole at the centre of Markarian 501, whose existence was already known, partially bends the light from the jet behind it into a so-called Einstein ring - Photo credit:

For years, astronomers had observed different orientations of the jet using radio telescope data, making it difficult to determine if its core really did harbor a supermassive black hole. To answer this question, the researchers analyzed over 83 datasets from the Very Long Baseline Array, an international network of 10 radio telescopes.

The results revealed that, instead of one large jet, there was also a second jet looping counterclockwise around the blazar's center. The team believes each of these jets is powered by a supermassive black hole, each weighing between 100 million and a billion times the sun's mass.

Comment: From Science Focus:

The two black holes orbit each other roughly every 121 days, separated by only 250-540 times the Earth-Sun distance - vanishingly small for objects of such colossal mass.

In June 2022, the geometry aligned so perfectly that light from the second jet was bent by the foreground black hole's gravity into a so-called 'Einstein Ring', adding further weight to the likelihood that the system is indeed two supermassive black holes.

"The binary model provides a self consistent solution," Britzen said. "Since these jets are directed towards us, an Einstein ring supports the scenario."

When the pair finally merge, the collision will send gravitational waves rippling across the Universe, far more powerful than those produced by the stellar-mass black hole mergers so far detected by observatories like LIGO.