Overview

• Published in Physical Review Letters, the analysis of GW250114 confirms with unprecedented precision that a merged black hole’s horizon area does not shrink, as Hawking predicted.
• Researchers isolated the post-merger ringdown and found the remnant consistent with a Kerr black hole, offering the most direct observational evidence yet for that model.
• GW250114 closely resembles 2015’s GW150914 but was observed roughly three to four times louder thanks to a decade of detector upgrades across the LIGO–Virgo–KAGRA network.
• International partners, including OzGrav and members of the LIGO-India Scientific Collaboration, contributed to the analysis, with LIGO-India targeting operations around 2030.
• LIGO Livingston plans a shutdown for upgrades later this year, and U.S. budget proposals that cut NSF funding have raised concerns about reduced LIGO operations.