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a Nobel Prize that could be


Did death betray Stephen Hawking of the Nobel Prize?

When the distinguished physicist died on March 14, 2018, data was already at hand that could confirm an ominous and far-reaching prediction he had made more than four decades ago. Dr. Hawking had assumed that black holes, those mouths of gravitational annihilation, could only get bigger, never smaller – as they swallow up information and threaten our ability to trace the history of the universe. put.

That data was obtained in 2015 when the Laser Interferometer Gravitational-Wave Observatory, or LIGO, recorded signals from two massive black holes that collided and created an even larger black hole.

Dr Hawking’s prediction was the first important step in a series of insights about black holes that have changed modern physics. At stake is whether Einsteinian gravity, which is what shapes the larger universe, follows the same rules as quantum mechanics, the contradictory laws that exist inside the atom.

Dr. Hawking’s prediction was confirmed In Physical Review Letters this summer. A team led by Maximiliano Isi, a physicist at the Massachusetts Institute of Technology, and his colleagues had spent years digging into the details of the LIGO results, and in July they finally announced that Dr. Hawking was right, at least in this particular black hole. Hole bump for color.

“This is an exciting test because it is a long-desired result that cannot be achieved in a laboratory on Earth,” Matthew Geisler, a Cornell University researcher and member of Dr. Isi’s team, said in an email. “This test required studying the merger of two black holes a billion light years away and simply could not have been accomplished without LIGO and its phenomenal detectors.”

The Nobel Prize makes no claim to knowing the mind of the committee, and the names of the nominees for the prize are kept secret for the next 50 years. But many scientists agree that Dr. ISI’s confirmation of Dr. Hawking’s prediction could have made Dr. Hawking – and his co-authors on a definitive paper about it – eligible for the Nobel Prize.

But the Nobel Prize cannot be given posthumously. Dr. ISI result came very late.

Nobel Prize week returns on Monday, when some scientists hope a phone call will anoint him as the laureate and call him December 10 at a grand ceremony in Stockholm. (This year, due to the pandemic, the prizes will be awarded to the winners’ home countries.)

Dr Hawking, arguably one of the most famous and respected researchers, never won a Nobel and never won now. His story is a reminder of how the ultimate prestige award is subject to the fickleness of fate.

The story begins in 1970, when Dr. Hawking was getting ready for bed one evening—a daunting task for a man who was already half-paralyzed with amyotrophic lateral sclerosis, or Lou Gehrig’s disease.

According to Albert Einstein’s theory of general relativity, he was thinking of black holes – objects with gravity so strong that not even light can escape them. They are portholes for infinity.

Each black hole is surrounded by an event horizon, an invisible bubble marking the boundary of no return; Whoever enters will never leave. Dr Hawking realized that Einstein’s theory also meant that the event horizon of a black hole could never shrink. A black hole only gains mass, so the total surface area of ​​its event horizon only increases.

It was a bold idea. Nature was not supposed to work that way. What if black holes could split in two, or break away from each other and disappear like a soap bubble?

Dr. Hawking’s insights became the cornerstone of a 1973 paper, “four laws of black hole mechanicsThat he wrote with James Bardeen, now at the University of Washington, and Brandon Carter, who is now at the French National Center for Scientific Research.

These laws also contained a disturbing conclusion to physics known as the “no hair” theorem. The surface area of ​​an event horizon is a measure of all the information ingested by a black hole. It’s the same for black holes whether it consumes matter or antimatter, Tesla or Volkswagen, ostriches or whales. Black holes have only three properties: mass, spin, and electric charge. No other description, or “child,” register.

This theorem meant that as a black hole got bigger and its event horizon got bigger, so would the amount of lost information about the things inside. The universe will become dumb and dim, hiding more and more details of its past, perhaps including your existence. The puzzle deepened in 1974 when Dr. Hawking calculated that a quantum effect would cause a black hole to slowly leak and burst.

The quest to understand what happens to information in black holes has transformed fundamental physics and energized a generation of young theorists. At stake is whether Einstein’s gravity, which governs the universe, and quantum mechanics, which governs the microcosm, operate by the same rules.

“It all started with Hawking’s realization that the total horizon area of ​​a black hole could never go down,” Dr. Isi said.

But with no black holes to experiment with, Dr Hawking’s ideas could not be tested.

LIGO will change that. Theoretical physicist at the California Institute of Technology and one of the founders of LIGO, Kip Thorne, made this promise to Dr. Hawking in 2003. The new array will be able to resolve the properties of black holes until Dr. Hawking’s time. Turned 70 in 2012.

“Your gift is that our gravitational-wave detectors – LIGO, GEO, Virgo and LISA – will test your golden age black-hole predictions, and they will start doing so well before your 70th birthday,” said Dr. Thorne. Recently remembering him said.

It took longer – until September 14, 2015 – for LIGO to observe its first epoch-making event: two colliding black holes. By matching the discovered wave patterns with computer simulations, the LIGO team concluded that one black hole was 36 times larger than our Sun and the other 29 times as massive – the equivalent of a total of 65 Suns. The collision resulted in the formation of a new black hole with a mass of about 62 Suns. Three suns of energy had disappeared in the gravitational waves that shook the universe.

The observations not only confirmed the existence of gravitational waves, as Einstein predicted 100 years ago, but provided the first direct evidence of a black hole.

A leaked copy of the Discovery paper reached Dr Hawking a few days before the official announcement of the findings. He was shocked to find no mention of the four laws of black hole mechanics, or the possibility that this discovery could test them. He Skyped the paper’s author, Dr. Thorne.

“Steven is quite surprised,” wrote Dr. Thorne to his colleagues.

No one had thought of checking the laws of black hole mechanics, and it was too late to add anything to the paper. Furthermore, as Dr. Thorne recently explained, the data was so noisy that measuring the size of the newly formed black hole was sufficiently sufficient to confirm Dr. Hawking’s theory.

In 2017, Dr. Geisler, then a graduate student at Caltech, and his colleagues used numerical simulations of colliding black holes to get a more in-depth look at the doomsday vortex.

When a newly merged black hole forms, it vibrates. Like a drum, it produces a fundamental tone as well as harmonics – overtones or undertones. The overtones came out surprisingly loud at the very beginning of the merging process, Dr. Geisler found. Using these vowels, he and his colleagues in 2019 “No hair” theorem proved, which states that black holes can only be described by three parameters.

This summer they were able to expand their analysis by exploiting an overtone of the new black hole to measure its size. They concluded that the region of the new black hole’s event horizon had increased, as predicted long ago by Dr. Hawking.

Would this have earned Dr Hawking the Nobel Prize if he were still alive?

“I don’t feel comfortable speculating,” said Dr. Thorne, who shared the 2017 Nobel Prize in Physics for his role in the development of LIGO.

Harvard’s Andrew Strominger, a longtime collaborator of Dr Hawking, said: “I don’t know about the deliberations of the Nobel Committee, but Hawking may have already been included in the award if he were still alive.” Certainly these most recent experiments will strengthen the case even further.”

Daniel Holz, an astrophysicist at the University of Chicago who is part of the LIGO collaboration but not part of Dr. Isi’s team, called the result “crazy cool”.

“Arguably this is an observational confirmation of one of his predictions,” he said. “I hope the Nobel Committee realizes this.”

The Physics Prize has always led to practical and experimental discoveries; Even Einstein won the prize for explaining the photoelectric effect, not for relativity. The Nobel Committee in Theoretical Astrophysics has gone the farthest as recently as 2020, when Roger Penrose of the University of Oxford was awarded the prize for proving that black holes were possible in the universe.

But he shared the prize with two astronomers, Reinhard GenzelMax Planck Institute for Extraterrestrial Physics, and andrea gezu, of the University of California, Los Angeles, who both studied the supermassive black hole at the center of the Milky Way.

Even if Dr. Hawking was still alive when his black-hole field theorem was proven, it would have been hard to fit him in – a Nobel Prize could be awarded to a maximum of three people. And what about Dr. Bardeen and Dr. Carter, Dr. Hawking’s co-authors? And the team of Dr. ISI?

Dr. Hawking would not be the first scientist to have died too soon for a possible Nobel Prize.

“I have been told that the Nobel Committee regrets not awarding Hubble,” Michael Turner, a prominent cosmologist now working for the Kavli Foundation in Los Angeles, told astronomer Edwin Hubble in an email. Wrote referring to those who discovered expansion. of the universe. “But he died first.”

Robert Brout, a theoretical physicist at the Université Libre de Bruxelles, would have been included in the 2013 Nobel Prize for predicting the existence of the Higgs boson, along with his collaborators François Engelert and Peter Higgs of the University of Edinburgh, had they not. . Died in 2011.

Ronald Drever of the University of Glasgow, one of the founders of LIGO, would have shared the 2017 Nobel with Dr. Thorne and MIT’s Rainer Weiss had they not died in early 2017. He was replaced by Caltech’s Barry C. was filled by rain. .

Dr Hawking rests next to Isaac Newton and Charles Darwin at Westminster Abbey. Maybe it’s better than spending the winter in Stockholm.



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