Hubert Reeves, astrophysicist and great popularizer, has died

With his patriarchal silhouette – bald head, white beard, sparkling blue eyes –, his lilting Quebec accent, his colorful and precise words, he embodied both the grandfather capable of telling us wonderful stories at the vigil and the druid mixing the ingredients of the Universe in his cauldron. A pint of Milky Way, an extract of the Moon, a few mysterious grains of dark matter… He explained to us that we were all made of stardust, because most of the elements that constitute us, such as carbon, oxygen and nitrogen, come directly from the stellar forges. At the end of his time on Earth, astrophysicist Hubert Reeves returned to this cosmic dust on October 13, 2023. He was 91 years old.

Seeing him perpetually gray, we almost forgot that he had been a child. However, Hubert Reeves, born July 13, 1932 in Montreal, often went back in time in his mind to his young years. He spoke of this large wooden family house overlooking Lake Saint-Louis, which his grandfather had built at the beginning of the 20th century.^e century and where he had so many memories: canoe trips, the call of his mother who made, at nightfall, a “Have you seen the sky?” »the cardboard board called “star seeker” which allowed young Hubert to identify the stars, and finally his maternal grandmother who absolutely must be named here, Charlotte Tourangeau, who had no equal for embellishing the stories by Perrault, extending or even mixing them according to his imagination, and to whom he owed his talents as a storyteller.

Theoretical physics

“What you value by saying “that’s interesting”, your children find valuablehe assured us during a meeting in 2002. My parents loved things related to natural sciences and so the idea that I would do science came to me very early. » Fond of mathematics, the young Reeves opted for theoretical physics, which he studied first in Montreal then in the United States, at Cornell University where, he remembered, “were the founders of nuclear astrophysics. The magic of the great American universities has taken place, where you feel capable of doing great things. There reigned a contagious creativity that gave wings. » At Cornell, he completed his thesis under the supervision of Edwin Salpeter (1924-2008), who became famous by showing how stars, by fusing three helium atoms, give birth to a carbon atom.

Hubert Reeves in turn plunges into the past of the Universe, understanding that to be an astrophysicist is to become the historian of the cosmos and matter. He is particularly interested in three light elements, lithium, beryllium and boron, too large to have been manufactured during the big bang but too fragile to have been designed in the thermonuclear fire of the stars. With Jean Audouze, the Canadian researcher shows that these elements are created when high-energy cosmic rays break up nuclei of carbon, oxygen or nitrogen present in space. “It’s an article that marked the era, assured us in 2018 the astrophysicist Michel Cassé who was one of Hubert Reeves’ doctoral students. Hubert had a very penetrating way of thinking about things in the sky.. He wasn’t sophisticated, he wasn’t a dandy: he really got straight to the point without being burdened with embellishments. »

In the early 1960s, Hubert Reeves taught in Montreal and became a scientific advisor to NASA. There he trained professors for the space science departments which were then being created in large numbers within American universities, as the conquest of space took off. But, uncomfortable with the nationalist atmosphere in Quebec and eager to explore other horizons, he wanted Europe. In 1964, he took a sabbatical and taught nuclear physics at the Free University of Brussels. Then he was invited to share his knowledge in France. It’s a turning point in his existence, he won’t leave again.

The popularizer

Research director at the CNRS and scientific advisor to the Atomic Energy Commission, Hubert Reeves has a well-defined career. His second life, that of popularizer, media darling and star storyteller, fell upon him somewhat by chance. Encouraged by friends, he wrote a first manuscript entitled Patience in the azure, in reference to a poem by Paul Valéry. He presented it to around thirty publishers who all refused to publish it, stupidly believing that astronomy interested no one despite the universal questions about the origins of the world to which it provided answers.

Hubert Reeves is preparing to put his manuscript in a drawer and remain the almost anonymous researcher that he is when the physicist Jean-Marc Lévy-Leblond, who directs the “Open Science” collection at Editions du Seuil, offers him… ‘write a book. Miracle, it’s already ready! Patience in the azure was published in 1981 and the French discovered, in the program “Apostrophes” by Bernard Pivot, this Quebecer who tells the cosmos as one reads a novel.

“I was told I would be lucky if three thousand sold. Today, we have exceeded a million copies and it has been translated into more than thirty languages…”Hubert Reeves told us in 2002. At the start of the 1980s, fame descended on him like a bird of prey on a field mouse, but he knew he had to be wary of it, keep it at bay: “Fame is destabilizing, intoxicating and a little dangerous: you risk getting a big head. Fortunately, my wife and friends are watching me. » The book-television-conferences cycle begins. Around thirty works will follow Patience in the azure, among which we can cite Stardust (Threshold, 1984), Latest news from the cosmos (Seuil, 1994), or his Memoirs entitled I will not have time (Threshold, 2008).

Environmental Defender

Every day, a request for conferences arrives in his mail and he binds himself to strict discipline, for whom too much involvement in his work has cost him a divorce followed by depression: it will therefore be one conference per week in France , one per month abroad. In total, he donated more than 2,500.

As if his two lives – researcher and popularizer – were not enough, Hubert Reeves took on a third: environmental defender. In 2001, he succeeded Théodore Monod at the head of the ROC League for the preservation of wildlife. A few years later, the association took the name Humanity and Biodiversity and he became its honorary president. His love of nature, inherited from his parents, never left him.

With his second wife, the journalist Camille Scoffier, he bought “an old dilapidated farm in Malicorne in Puisaye”, as he recounts in his Memoirs. There are century-old oaks there but Hubert Reeves wants to go further by creating what he calls “the thousand-year-old forest, trees that can live for more than a thousand years: Lebanese cedars, redwoods, lime trees, ginkgoes”.

Distressed by global warming, pollution and the loss of biodiversity that he himself observes in the garden of his country house, he puts his notoriety at the service of the ecological fight. He writes columns, calls on mayors, parliamentarians and candidates for the 2012 presidential election. “In Malicorne, I had seen him for a long time take a deep interest in plants and birds, which meant a lot to him,” Michel Cassé told us in 2018. Which summed up his friend’s journey as follows: “After skimming the sky, he became passionate about the Earth. »

In I will not have time, Hubert Reeves assured that we could see astronomy and ecology “like two parts of the same theme: our existence. Astronomy, by telling us the history of the Universe, tells us where we come from, how we came to be here today. Ecology, by making us aware of the threats weighing on our future, aims to tell us how to stay there. »