Biggest-Ever Black Hole Merger Detected

In July 2025, an international collaboration of gravitational wave observatories under the LVK network announced the detection of GW231123 — the most massive black hole merger ever observed, offering groundbreaking insights into the evolution of the universe.

Key Points

Record-Breaking Merger: Two black holes, with masses of 140 and 100 times that of the Sun, merged to form a black hole of around 225 solar masses — the largest observed through gravitational waves.
LVK Collaboration: Detection was made by LIGO (US), Virgo (Italy), and KAGRA (Japan). LIGO-India is currently under development, with Indian scientists already part of the collaboration.
Rare Intermediate-Mass Black Holes: The discovery challenges current models, as stellar-collapse black holes are usually below 60 solar masses and the event hints at hierarchical mergers forming supermassive black holes.
Indian Contribution: IIT Bombay’s team played a pivotal role in detection algorithms. Professor Archana Pai and alumnus Koustav Chandra were key contributors to the discovery and analysis.
Theoretical Significance: The fast-spinning and massive nature of the black holes raises new questions about their formation.