Scientists have made a significant advancement that backs up a theory put forth by famed physicist, Stephen Hawking, more than 50 years ago.
Experts have used a gravitational wave detector to “hear” two black holes getting bigger as they merged into a single, gigantic entity. This detection, made by the Laser Interferometer Gravitational-wave Observatory (LIGO) on January 14, provides the best evidence to date for Hawking’s theory.
The remarkable mind failed to prove the theory during his lifetime, but the new research, which was published on September 10 in the journal Physical Review Letters, may prove him correct.
The study was led by Adrian G. Abac, a doctoral student at the Max Planck Institute for Gravitational Physics in Potsdam, Germany.
LIGO is a project, set up in 1992, that detects gravitational waves – ripples in the fabric of space-time released during the most extreme events in the cosmos, such as collisions of black holes or neutron stars (the remnants of giant stars).
Its first direct detection of gravitational waves was made almost exactly 10 years ago on September 14, 2015, confirming Albert Einstein’s predictions of general relativity by observing two black holes merging.
Now, LIGO has made many improvements to the detectors, allowing them to spot black hole mergers about once every three days instead of once a month, according to a statement from Caltech, which jointly operates LIGO along with MIT.
During the event on January 14, LIGO observed two black holes merging, with the resulting black hole measuring significantly bigger than the two objects entering into the collision.
According to the research, before the merger, the combined surface area of the two black holes was roughly the size of Oregon. After, the newly formed, single black hole was about the size of California. In other words, the newly merged black hole was larger than the sum of its parts.
The detection of the growing black hole confirmed Hawking’s prediction, that the outer boundary of a black hole “beyond which nothing can escape – can never decrease in size,” researchers at Columbia University, which is part of the LIGO Collaboration, said in a separate statement.
Study co-author Maximiliano Isi, assistant professor at Columbia University said the discovery has “immense implications,” and now has scientists treating black holes as “thermodynamic objects.”
LIGO also made a 2021 discovery that tentatively confirmed Hawking’s prediction. However, the new results, “confirm this earlier result with a much higher precision,” Columbia officials added.
The study achieved this precision by examining the pitch and duration of the gravitational waves emitted as the black holes merged. The event produced a “ringing” in space-time as the new black hole quieted down after the merger.
Researchers can make inferences about the black holes through their waves because a black hole’s size and shape influence these waves, in much the same way a musical instrument’s size and shape affect the sound it makes.