Physicists say they’ve proven a major black hole theory proposed by Stephen Hawking

A group of scientists this week announced that they had confirmed a theory proposed years ago by eminent physicist Stephen Hawking regarding the physical properties of black holes.

The U.S.-based physicists in the journal Physical Review Letters said they had discovered “observational confirmation of Hawking’s black-hole area theorem.”

That theorem, first proposed by Hawking five decades ago in 1971, holds that the “event horizon” of a black hole—the boundary within which nothing in the universe can escape the gravity of the astronomical object—can never shrink and can only grow larger. 

The scientists to test that theory examined the data of gravitational waves, a long-postulated phenomenon first detected in 2015 from the merger of two black holes; they reported confirmation of that finding with 95% confidence. 

The researchers also said the data from the gravitational waves was “consistent with the same remnant mass and spin” in the merged black hole, an observation “in agreement with general relativity.”