Researchers from Purple Mountain Observatory have conducted an observational test of the black hole area law. Using the gravitational-wave event GW230814, which features a high signal-to-noise ratio, the team closely examined the event horizons of merging black holes. The black hole area law, first proposed by Stephen Hawking in 1971, predicts that the total event horizon area after a merger wil Tokyo, Japan (SPX) Nov 15, 2025
Researchers from Purple Mountain Observatory have conducted an observational test of the black hole area law. Using the gravitational-wave event GW230814, which features a high signal-to-noise ratio, the team closely examined the event horizons of merging black holes. The black hole area law, first proposed by Stephen Hawking in 1971, predicts that the total event horizon area after a merger will not decrease compared to its original sum.
The team divided the black hole coalescence into three phases: inspiral, merger, and ringdown. The merger phase presents a highly dynamic regime and is especially suited for testing general relativity. By performing separate parameter estimates for the inspiral and ringdown phases, the researchers determined the masses and spins necessary to calculate the horizon areas of both the original and final black holes.
Their analysis robustly accounted for uncertainties including sky location, waveform model systematics, ringdown model variations, and phase boundaries. Results show an extremely high probability that the final black hole's horizon area exceeds the combined areas of the two progenitors. The statistical significance for this outcome is up to 4.1 sigma.
These findings strongly validate Hawking's area law and support the reliability of general relativity in the regime of strong gravity and rapid dynamics. The work offers a solid foundation for further investigations into black hole thermodynamics, quantum gravity corrections, and advanced gravitational theory testing.
Science Bulletin:Verification of the black hole area law with GW230814
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