**This study provides evidence based on gravitational waves showing that the total area of the black hole event horizon can never be reduced.**

There are certain rules that must be followed even in the most extreme things in the universe. The central law of black holes predicts that the area of the event horizon – the boundary from which nothing can escape – should never be reduced. This law is a theory in the field of Hawking, named after the physicist Stephen Hawking, who adopted this theory in 1971.

Fifty years later, physicists at MIT and elsewhere first confirmed the theory of Hawking zones by observing gravitational waves. Their results appear today (July 1, 2021) *Physical examination reports*.

In the study, researchers scrutinized GW150914, the first gravitational wave signal detected by the Gravity Wave Observatory (LIGO) laser interferometer in 2015. The signal is the result of two inspired black holes. . Large amounts of energy are transmitted through space in the form of gravitational waves.

If the Hawking region theory is correct, the horizon area of the new black hole should not be less than the total horizon area of the original black holes. In a new study, physicists re-analyzed the signal from GW150914 before and after a space crash and found that the total area of the event horizon does not decrease after fusion – they report the result with 95% confidence.

Their findings represent the first direct observational confirmation of Hawking’s theory of zones, which has been mathematically proven but not yet observed in nature. The team plans to examine whether future gravitational wave signals will further confirm Hawking’s theory or be a sign of distorted laws.

“It’s possible to have a zoo of various compact objects, some of which are black holes regulated by the laws of Einstein and Hawking, but others,” said Maximiliano AC, MIT’s postdoctoral fellow. Various monsters. Cowley Institute for Astrophysics and Space Research. “So it’s not like you’re successful in this experiment once and it ended. You do it once, that’s the beginning.”

Will Farr of Stony Brook University, Flatiron Center for Computational Astrophysics, Matthew Geissler of Cornell University, Mark Schel of Caltech, and Saul Tyukolsky of Caltech, Cornell University.

**The age of visions**

In 1971, Stephen Hawking put forward a theory about this region, which presented basic ideas about the physics of black holes. The black hole is the total area of the event horizon – so the theory predicts that all black holes in the universe will never decrease. This statement was parallel to the second law of thermodynamics, which states that the entropy or the magnitude of failure of an object should never decrease.

The similarity between the two theories suggests that black holes can behave like heat-emitting thermal objects, which is confusing because black holes, by their very nature, never allow leakage or radiation. Hawking finally split the two concepts in 1974, claiming that black holes could have entropy and emit radiation over a long period of time, given the quantum effects. This phenomenon is called “Hawking’s radiation” and is one of the most basic discoveries of black holes.

“It all started with Hawking’s realization that the total area of the black hole horizon could never be reduced,” says EC. “District law is an example of the golden age of the 1970s, when all these ideas were made.”

Hawking and others have proven that area theory works mathematically, but there is no way to test it against nature until LIGO first discovers gravitational waves.

After hearing the results, Hawking quickly contacted LipGo co – founder Kip Thon, a professor of theoretical physics at Feynman’s Caltech. His question: Can the discovery confirm the theory of territory?

As Hawking’s theory suggests, scientists did not have the ability to copy the required information in the signal before and after the merger. A few years later he was able to develop the technology of IC and his colleagues in testing legislation in this area.

#### Before and after

In 2019, IC and colleagues developed the Echo Extraction Technique from the top of the GW150914 – the moment two real black holes collide and create a new black hole. Using this technique, the team selected specific frequencies or tones for the loudest effects that could be used to estimate the final mass and rotation of the black hole.

The mass and rotation of a black hole are directly related to the region of its event horizon, and Thorne approaches them, referring to Hawking’s question with the following observation: Can they use the same technology to compare the signal before and after the merger? To confirm the theory of territory?

Scientists accepted this challenge and again delivered the GW150914 signal to its peak. They developed a model to analyze the signal at the peak corresponding to the excitation black holes and to determine the mass and rotation of the two black holes before merging. From these figures, they calculated the total horizons – approximately 235,000 square kilometers, which is eighty times the size of Massachusetts.

They used previous technology to extract the “ring” or reflections of the new black hole, which they say fits 367,000 square kilometers (approximately 13 times the size of the Bay State), and to estimate its mass, rotation, and finally its horizon. .

“The data show that the area of the horizon has increased since the merger and the law in this area is likely to be satisfied,” says EC. “We are relieved that our results fit the pattern we expect and confirm our understanding of the complex fusions of black holes.”

The team plans to conduct further tests on Hawking’s theory and other long-standing theories of black hole mechanics using data from its counterparts in Italy, LIGO and Virgo.

“It’s encouraging to think about gravitational wave data in a new and innovative way and to come up with questions that we previously thought we could not do,” says EC. “We can continue to talk directly to the subcontractors of things we think we understand. One day, this data may reveal something we did not expect.”

Reference: “GW150914 with Black Hole Low Test,” Maximiliano AC, Will M. Far, Matthew Geissler, Mark A.. Shell, Saul a. Tikolsky, July 1, 2021, is available here. *Physical examination reports*.

DOI: 10,1103 / PhysRevLett.127.011103

The research was partially supported by NASA, the Simmons Foundation and the National Science Foundation.