Some of his theories have been so successful that he claims to have been "disappointed" – that he had already invented others in case they failed to describe the cosmos. But the Canadian James Peebles was able to enjoy this success yesterday when he was awarded the Nobel Prize in Physics.
"I now know how rock stars feel," the 84-year-old applauded at a ceremony at Princeton University in New Jersey where he worked and taught his entire career. The Canada-US cosmologist shared the Nobel with two Swiss scientists, Michel Mayor and Didier Queloz. These have been rewarded for separate works, namely the discovery of an exoplanet orbiting a star similar to the Sun.
"This year's award recognizes contributions to our understanding of the evolution of the Universe and Earth's place in the cosmos," said Göran K. Hansson, Secretary General of the Royal Swedish Academy of Sciences. .
The great legacy of Mr. Peebles is that he has helped to make it clear that everything we see and know, from stars to galaxies to human beings, represents just 5% of the Universe. The rest is made of dark energy and dark matter. Mr. Peebles' theory of the cosmos also explains the cosmic background radiation that comes from the very first instants of the Universe.
"Do not aim for prizes and medals," said the youth present in the auditorium who had just been honored with the highest award in his discipline. "We are in there for the joy of research, fascination and the love of science. "
Note that after Donna Strickland last year, this is the second time in a row that a Canadian is honored with the Nobel Prize in Physics.
Modesty and ice cream
Nathalie Ouellette, coordinator of the Exoplanet Research Institute of the Université de Montréal, is a specialist in extragalactic astrophysics. His work is based on the theories of Mr. Peebles, a man she has met several times.
"He's super nice, very modest. And he's a great physicist, "she commented The Press. According to Mme Ouellette, James Peebles played a great role in uniting theoretical cosmologists like him to astronomers who made observations. "When he emitted a theory, he was working with observational astronomers to see what kind of observational program could validate that theory," she says. Among his generation, it was not common. But thanks to its openness, a whole new generation of astronomers has emerged, which are both theoretical and observational. "
Princeton University President Christopher Eisgruber took advantage of a telecast conference to describe the winner as "an extraordinary physicist, a man who has thought deeply and clearly about the structure of the Universe". The human qualities of the scientist, such as his modesty and curiosity, were also emphasized.
As passionate about teaching as it was about research, Peebles was known for giving "ice cream breaks" to his students. "He taught himself with a horn in one hand and a chalk in the other," said Eisgruber, who had him as a teacher.
I benefited immensely from the fact that when you stand in front of students, who are brilliant people, you must know what you are talking about. This has profoundly enhanced my knowledge of physics.
The little guy from St. Boniface
James Peebles was keen to correct the Princeton presenter who claimed he was born in 1935 in Winnipeg. "I was born in St. Boniface, the sister city of Winnipeg," he said. After graduating from the University of Manitoba, he continued his studies at Princeton, where he taught his entire career. He says that theoretical cosmology was at the time an unpopular area that frightened him a bit, because the experimental data was so small that it was difficult to validate the theses.
But I could think of a thing or two to do in cosmology, and each of them led to something else. I only continued, it was such a pleasant adventure.
There is a saying in science that questions are more important than answers. However, Mr. Peebles believed in it so much that he was sometimes disappointed when his theories were experimentally verified. This is for example the case with his theory of "cold dark matter", one of his most important contributions.
"In 1984, when I issued this theory, I was very sorry to see that it attracted so much attention. Why put so much emphasis on this theory? I can invent a dozen others that match the data as well. (…) I spent some of the 80s and 90s inventing other theories, simply because I felt that we should not have so much confidence in the first. But I was completely wrong, "he said.
He admits that the mystery of dark matter, whose existence he has helped to postulate, but which has not yet been detected experimentally, still teases him. "She's here, it's insulting, but she's here. But she will end up showing herself, it always ends like that, "he said.
James Peebles is awarded half of the Nobel 9 million Swedish Nobel Prize (about 1.2 million Canadian dollars), the other half being shared by the two Swiss researchers. He promised to donate some of it to charities and the University of Manitoba.