Discovery of the Heaviest Supermassive Black Hole Pair Stalled in Merger

Astronomers have identified a binary supermassive black hole system, weighing 28 billion times the sun, unable to merge due to its massive size.

Two supermassive black holes in the elliptical galaxy B2 0402+379 form the heaviest binary system ever discovered, with a combined mass of 28 billion solar masses.
The black holes are separated by just 24 light-years, the closest distance ever measured for such a pair, yet their merger has been stalled for over 3 billion years.
The massive size of the black holes has scoured their surrounding area of stars and gas, leaving insufficient material to drive them together for a merger.
Archival data from the Gemini North telescope was crucial in determining the black holes' mass and understanding the dynamics of their stalled merger.
The discovery challenges existing theories on supermassive black hole mergers and highlights the role of mass in determining the fate of these cosmic giants.