Nobel Prize in Physics Awarded to 3 Scientists for Work on Black Holes

The Nobel Prize in Physics was awarded to three astrophysicists Tuesday for work that was literally out of the world, and indeed the universe. They are Roger Penrose, an Englishman, Reinhard Genzel, a German, and Andrea Ghez, an American. They were recognized for their work on the gateways to eternity known as black holes, massive objects that swallow light and everything else forever that falls in their unsparing maws.

Dr. Penrose, a mathematician at Oxford University, was awarded half of the approximately $1.1 million prize for proving that black holes must exist if Albert Einstein’s theory of gravity, known as general relativity, is right.

The second half was split between Dr. Genzel and Dr. Ghez for their relentless and decades long investigation of the dark monster here in the center of our own galaxy, gathering evidence to convict it of being a supermassive black hole.

Dr. Ghez is only the fourth woman to win the Nobel Prize in Physics, following Marie Curie in 1903, Maria Goeppert Mayer in 1963 and Donna Strickland in 2018.

“I’m so thrilled” she said in an email.

The Nobel Assembly announced the prize at the Royal Swedish Academy of Sciences in Stockholm.

Black holes were one of the first and most extreme predictions of Einstein’s General Theory of Relativity, first announced in November 1915. The theory explains the force we call gravity, as objects try to follow a straight line through a universe whose geometry is warped by matter and energy. As a result, planets as well as light beams follow curving paths, like balls going around a roulette wheel.

Einstein was taken aback a few months later when Karl Schwarzschild, a German astronomer, pointed out that the equations contained an apocalyptic prediction: In effect, cramming too much matter and energy inside too small a space would cause space-time to collapse into a point of infinite density called a singularity. In that place — if you could call it a place — neither Einstein’s equations nor any other physical law made sense.

Einstein could not fault the math, but he figured that in real life, nature would find a way to avoid such a calamity.

In 1965, however, a decade after Einstein’s death, Dr. Penrose slammed the door on Einstein’s hopes.

Born in 1931 into an intellectual family, Dr. Penrose is a professor at the University of Oxford. When he was a child, he recalled in a recent interview, his father and his brother would play mental chess on family hikes, and his job was to keep track of the board.

A talented mathematician, he invented a new way of portraying space-time, called a Penrose diagram, which bypassed most of the mathematical complexities of general relativity.

His diagrams are now the lingua franca of cosmology. He proved that if too much mass accumulated in too small a place, collapse into a black hole was inevitable. At the boundary of a black hole, called the event horizon, you would have to go faster than the speed of light — the acknowledged cosmic speed limit — to get away. So you could never escape. Inside the boundary, time and space would switch roles and so all directions would lead downward, to the center, where the density became infinite and the laws of physics, as we knew them, would break down.

He showed that the black hole would become a gateway to the end of time, the end of the universe.

He is also famous for discovering Penrose tiles, a way of tiling an infinite floor without ever repeating the pattern. He has also published iconoclastic views of artificial intelligence and the origins of consciousness in books like “The Emperor’s New Mind: Concerning Computers, Minds and the Laws of Physics.

Today, astronomers agree that the universe is speckled with such dark monsters, including beasts lurking in the hearts of most galaxies that are millions and billions of times as massive as the sun. They’ve even taken a picture of one in a galaxy some 55 million light-years away.

Over the years, their observations have crept closer to the conclusion that whatever is at the galactic center is dark and must have a mass equivalent to four million suns, in order to exert enough gravitational pull to keep the stars and gas that circle it in check.

One of the stars, which Dr. Genzel calls S2 and Dr. Ghez calls S0-2, is a young blue star that follows a very elongated orbit and passes within just 11 billion miles, or 17 light-hours, of the mouth of the putative black hole every 16 years.

During these fraught passages, the star, yanked around an egg-shaped orbit at speeds of up to 5,000 miles per second, should experience the full strangeness of the universe, according to Einstein. That last happened in the summer of 2018, with both teams watching for deviation or surprise from the star.

To conduct that experiment, astronomers needed to know the star’s orbit to a high precision, which in turn required decades of observations with the most powerful telescopes on Earth.

“You need 20 years of data just to get a seat at this table,” said Dr. Ghez, who joined the fray in 1995.

In fall 2018, Dr. Genzel announced that they had detected the gas clouds circling the center of the galaxy every 45 minutes or so at 30 percent the speed of light. Those clouds are so close to the suspected black hole that if they were any closer, they would fall in, according to classical Einsteinian physics, Dr. Genzel said.

The results provide “strong support” that the dark thing in Sagittarius “is indeed a massive black hole,” Dr. Genzel’s group wrote in the journal Astronomy & Astrophysics in 2018.

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