Three scientists share Nobel prize in physics for work on black holes
Three scientists have won the 2020 Nobel prize in physics for their work on black hole formation and the discovery of a supermassive black hole at the centre of our galaxy.
Sir Roger Penrose, Reinhard Genzel and Andrea Ghez together scooped the 114th Nobel prize in physics.
The award, announced on Tuesday, is presented by the Royal Swedish Academy of Sciences and is worth 10m Swedish kronor (£870,000), which will be shared among the winners, with half going to Penrose and the other half shared between Genzel and Ghez.
Mysterious, exciting and inescapable, black holes form when an enormous mass is squashed into a small space, as occurs when massive stars collapse. The result is an object where gravity is so strong that a oneway street is formed; not even light can escape, meaning black holes are invisible, while to distant observers time appears to stand still in the region surrounding it that is known as the event horizon.
Prof Penrose, a British mathematical physicist based at the University of Oxford, won his share of the prize for using innovative mathematical techniques to prove that the formation of black holes is an inevitable consequence of Einstein’s general theory of relativity, and hence can truly exist.
His groundbreaking paper, published in 1965, would have been a surprise to Einstein who himself had previously declared in a paper in 1939 that black holes “do not exist in physical reality”. Among subsequent work, Penrose joined forces with Stephen Hawking, and produced new ideas on when gravitational singularities are formed – these are points of infinite density as found in the centre of black holes.
Prof Genzel is a German astrophysicist who is the director of the Max Planck Institute for Extraterrestrial Physics, while Prof Ghez is an American who works at the Department of Physics and Astronomy at the University of California, Los Angeles.
Together, Genzel and Ghez were honoured for work in which they turned telescopes on our own galaxy and discovered, by looking at the motions of stars, evidence of a supermassive object in the centre of the Milky Way, an object that experts say can only be a black hole. This black hole, known as Sagittarius A*, is thought to have a mass equal to that of about 4m suns and a diameter of 24.2m km (15m miles).
Ulf Danielsson, professor of theoretical physics at Uppsala University in Sweden, said: “This year’s laureates
have uncovered secrets in the darkest corner of our universe. But this is not just an old adventure coming to its triumphant conclusion, it is a new one beginning. As we probe ever closer to the horizons of the black holes, nature might have new surprises in store.”
Ghez, only the fourth woman to be awarded a Nobel prize in physics, said she was thrilled. “I hope I can inspire other young women into the field. It is a field that has so many pleasures, and if you are passionate about the science there is so much that can be done,” she added.
The announcement of the winners was delayed, the committee said, due to difficulties in contacting the winners.
Penrose, 89, told the Guardian it was a “huge honour” to win the prize, and that it was wonderful to hear that the award had also gone to a woman. But, somewhat sheepishly, he added that the win was likely to disturb his current work for a few days.
“In some ways it is a distraction, I hate to say this,” he said, adding that he’d been making the most of lockdown to develop new ideas.
Penrose said the win would not stop him working on his latest theories.
“I always thought it is a good thing not to win the Nobel prize too early, because if you get it too early … that is what you are thought of,” he said.
Dr Ziri Younsi, of University College London, an expert on black holes, was enthusiastic about the news. “Black holes are fascinating and enigmatic objects,” he said. “It is wonderful to see the fundamentally important theoretical and observational work of these laureates recognised by the Nobel committee.
“The future of compact object physics and our quest to understand black holes is picking up pace, and hopefully there will be more Nobel prizes on this topic in the years ahead.”
The Nobel prize in chemistry will be announced on Wednesday.