Hubert Reeves (1932-2023) died on October 13 at the age of 91. The famous astrophysicist in the French-speaking world is mainly known as an effective science popularizer and an ardent defender of the natural environment.
In the 1960s and 1970s, he conducted research on stellar evolution and nucleosynthesis in stars and the young universe. The study of nucleosynthesis aims to understand the manufacture of the 92 natural elements that make up the periodic table; the elements made in stars constitute the building blocks of everything in the Universe. “We are made of stardust,” Reeves wrote again and again.
A very particular aspect of the elements caught Reeves’ attention, namely the intriguing underabundance of certain light elements. With French colleagues, he worked to explain the surprising rarity of three light elements in stars and the interstellar medium: lithium (Li), beryllium (Be) and boron (B) are millions of times less abundant than ‘expected. They are considered “light” because they are metals that contain only three, four and five protons respectively.
These three elements have acquired crucial importance in today’s technologies. For example, the mirrors of the James Webb Space Telescope are made of beryllium; lithium is omnipresent in batteries. Reeves and his colleagues demonstrated that nuclear processes at the centers of stars and cosmic ray stripping of the interstellar medium destroy fragile Li-Be-B cores, thereby reducing their content in cosmic matter over time.
A long collaboration and a beautiful friendship
As a doctoral student, I discovered Reeves’ work through his book Stellar Evolution and Nucleosynthesis (1968). This subject was then at the forefront of astrophysics research. Reeves received his doctorate (1960) under the supervision of Austrian-Australian-American astrophysicist Edwin Salpeter of Cornell University, New York. At the time, I thought Reeves was an American astronomer.
In the early 1980s, when I was a young professor at Laval University in Quebec, I received a request from the Presses de l’Université du Québec to evaluate a manuscript, Patience in the blue. Cosmic evolution, the author of which was the same Reeves. I evaluated the proposed work in the most positive way, ironically saying that it could be the equivalent for the French readership of the famous book Cosmos, of the American astronomer Carl Sagan; the latter book inspired the famous television series of the same name.
My joke turned out to be true since Patience in the azure, co-published with Éditions du Seuil in Paris, sold hundreds of thousands of copies. For me, this bookish encounter was also the beginning of a collaboration and a friendship. Reeves prefaced my first book, Astronomy and its history (1983); he made a critical and constructive reading of my manuscript The heirs of Prometheus (1998).
For several years, every fall, Reeves, who had lived and worked in Paris since 1965, visited family and friends in Montreal and Quebec. He took advantage of these opportunities to give advanced seminars to master’s and doctoral students at the University of Montreal and Laval University. Each visit was also an opportunity for exchanges with the general university public and the general public; these conferences, several of which I chaired, were always very well attended, particularly those on the cosmology of the big bang and on the evolution of the Universe. Thanks to two generous donations from Reeves, the Hubert-Reeves Scholarships were also created at both universities, awarded each year to a graduate student from each of the two establishments.
Reeves was an outstanding writer, with a clear, poetic style that captivated readers of all ages; he was able to explain complex phenomena in simple terms and with effective analogies. Over time, attendance at his conferences has increased phenomenally. Some saw him as a sort of guru. The media were after him and he became a sort of “star”. His welcoming grandfather appearance and his simplicity were a little deceptive, because he could be reluctant with journalists who were too curious or with the few impostors of all kinds who sought to attract attention.
Many incorrectly assumed that what Reeves said or uttered was shared by all scientists. Some of my colleagues have criticized his pontificating approach. When he declared that there were limits to the power of science to explain everything, some zealous listeners inferred that he was tacitly supporting pseudoscience.
An extraordinary scientist
Despite this, Reeves remained an extraordinary teacher and pedagogue. He has published more than 40 books on science and nature, the vast majority of them aimed at a wide audience, including children. He brought together some of his talks on more advanced cosmology into a very effective book with a scholarly track and a more popular track, Latest news from the cosmos, published in two volumes (Éditions du Seuil).
As I traveled frequently to France in the late 1980s and 1990s, I met Reeves regularly. He and his wife Camille invited me a few times to their magnificent estate in Malicorne, Burgundy. The Reeves had purchased and converted the farm buildings of an old castle; they renovated and maintained this little paradise with magnificent trees and splendid flower beds where insects and birds were constantly busy.
I remember the beautiful library with its thousands of books and, on the walls, the paintings of their artist friends. The grand piano in the middle of the room was a clear message of the owners’ interest and passion. Reeves loved music, especially Mozart. However, he did not like organ music; perhaps it reminded him of the stern atmosphere of the church of his childhood. Reeves played the piano, but he particularly enjoyed visits from musician friends.
Over the years, Reeves became very concerned about human impacts on nature; he clearly tried to demonstrate and constantly repeated that the decline in biodiversity endangers the survival of humanity. He is strongly committed to defending the environment, putting his energy and knowledge at the service of various causes. When I told him that he should spend more time sharing and explaining the concepts of science, he replied that others could do it as well or better than him… In my mind, there remains a extraordinary scientist and a wonderful teacher.