Astrophysicist Hubert Reeves

Hubert Reeves, CC OQ (1932) is a French Canadian astrophysicist and populariser of science.

I found this interesting anecdote about Reeves, in a Swiss train:

Hubert Reeves looked out the window. The Alps, magnificent and snowcapped, caught his eye as the train rounded a curve on its way from Geneva to Berne, Switzerland. It was October 1970. Beneath the mountains, an autumn patchwork of gold and vermilion framed a winding brook. Reeves briefly wondered if its source was melting snow, and then it came to him, the answer to the puzzle. The stream triggered a memory, a scene from a movie about mountains and cold water: La Bataille de l'eau lourde (The Battle for Heavy Water). The 1947 French film by Jean Dréville tells the true story of how, near the end of World War II, Allied commandos destroyed a top-secret heavy-water plant in the mountains of Norway. The Nazi invaders were going to use the heavy water to make an atom bomb.

Heavy water, heavy hydrogen ... Reeves’ mind flashed: You extract heavy water from ordinary water at super-cold temperatures and it takes a long time ... That was it! He now felt he could explain the huge discrepancy in recent experimental results about the nature of the solar wind, the huge flux of atomic particles blown into space by the burning sun.