Overview

• Reanalysis of GW190412, detected by LIGO and Virgo in 2019, finds the remnant black hole recoiled at about 31 miles per second (50 km/s) based on subdominant waveform modes.
• The unequal masses of the progenitors (approximately 30 and 8 solar masses) made higher-order harmonics detectable, enabling the team to infer the kick direction and orbital geometry.
• The measured speed is sufficient to eject the remnant from its birth star cluster, shaping expectations for hierarchical black-hole growth and merger rates.
• Researchers shared a human-audible rendering of the signal that highlights the harmonics used to decode the remnant’s motion.
• In a separate 2025 study, upgraded LVK detectors captured high-fidelity event GW250114, allowing precise ringdown tests that bolster Hawking’s area law and the Kerr description of black holes.