The LIGO‑Virgo‑KAGRA Collaboration announced the first likely detections of "second-generation" black holes — black holes formed from previous mergers — via two gravitational-wave events in late 2024 (GW241011 and GW241110). These events featured unusual signatures: significantly unequal masses and high or retrograde spins, which imply the larger black holes may themselves have arisen from earlier collisions in dense cosmic environments. The findings strengthen evidence for hierarchical mergers and offer new precision tests of Albert Einstein’s general relativity under extreme conditions.

Authors: LIGO‑Virgo‑KAGRA Collaboration, Prof. Francesco Pannarale