## โคlandmark LIGO Observation Confirms โHawking’s Black hole Area Theorem with Unprecedented Precision
Recent observations by the Laser Interferometer Gravitational-wave Observatory (LIGO) have provided the strongest confirmationโค yet of a โfundamental theoremโ proposed by the late Stephen hawking: the blackโข holeโ area theorem. This โtheorem states that the total area of a black hole’s event horizon โcan never decrease over time, even when black holes merge.
The โคconfirmation stems from the analysis of gravitational waves emitted during the merger of two black holes, designated GW250114 – a signal detected on January 14, 2025. While similar to LIGO’s โfirst detection in 2015 (GW150914),โฃ involving black holes approximately 1.3 billion light-yearsโข away with masses 30 toโค 40 times that of our sun, the GW250114 signal โฃwas significantly โclearer due toโ a decadeโ of advancements in detector technology. These improvements haveโ made the LVK detectors – LIGO, Virgo, and KAGRA – the most precise measurement tools ever created, capable of detecting distortions in spacetimeโ smaller than 1/10,000โข the width of a proton. (Virgo and KAGRA were offline during this specific observation.)
By meticulously analyzing the frequencies of the gravitational waves,the LIGO team was able to provide the best observational evidence to date supporting Hawking’s theorem. The team focused on the “ringdown” phase of the merger -โค the period after the blackโ holes coalesce when the newly formed black hole vibrates, analogous to a struck bell.
Researchersโข were able, for the first time, to confidently identify two distinctโ gravitational-wave modes within this ringdown phase. These modes, similar โขto theโค different tones a bell produces, decay at different rates โand areโค notoriously arduous to distinguish.Extracting โthese modes allowed the team to preciselyโ calculate the โขmass and spin of the resulting black hole,and subsequently,its surface area.
This newโ analysis achieved a โconfidence level of 99.999%, a substantial improvementโข over a previous test performed in 2021 using the GW150914โ data, whichโฃ yielded a confidence level of 95%.The confirmation is particularly poignantโฃ given hawking’s long-held beliefโ in โthe testability of his โtheorem using gravitational wave detectors. Nobel Laureate Kip Thorne recounts Hawking inquiring about LIGO’s potential to verify the theorem shortly after the initial gravitational wave detection in โ2015. Sadly, Hawking passed away in 2018 and did not live to witnessโข the observational โconfirmation of his work. Thorne noted that Hawking “would have reveled โขin seeing the area of theโ merged black holes increase.”
The research, published in *Physical Review Letters* (https://doi.org/10.1103/kw5g-d732), represents a significant milestone in our understanding of blackโข holes and the fundamental laws governing โthe universe.