Gravitational Wave Study Proves Stephen Hawking Was Right About Black Holes
The new discovery, recorded on January 14 from a merger of two black holes 1.3 billion light-years away, was a virtual copy of that first detection. Still, thanks to a decade of technological improvements, LIGO's detectors were able to record the signal in greater clarity. This allowed scientists to confidently confirm Hawking's area theorem, a long-contested idea he proposed in 1971.
Hawking's theorem states that the total surface area of a black hole’s event horizon—the point of no return—can never decrease. When two black holes merge, the new, larger black hole must have a surface area at least as big as the combined areas of the two original black holes.
This principle is a parallel to the second law of thermodynamics, which states that the entropy, or disorder, of a closed system always increases. By measuring the "ringdown" phase of the newly formed black hole—the way it vibrates like a struck bell after the merger—researchers were able to calculate its mass, spin, and ultimately its surface area. The data showed with overwhelming confidence that the final black hole's area was indeed larger, confirming Hawking’s decades-old law.
This observational proof is a bittersweet achievement, as Hawking, who died in 2018, did not live to see his theory verified in this way. The finding reinforces our understanding of black holes as thermodynamic objects and offers a crucial link to unify general relativity and quantum physics.
Since the initial discovery in 2015, LIGO, along with its partners Virgo and KAGRA, have detected more than 300 gravitational waves and are providing a unique view of the universe's "dark side," revealing details about objects like colliding neutron stars and black holes that do not emit light.
