Fermi in the Alps

In July 1954, Enrico Fermi took a beautiful and possibly quite dangerous trip to the French Alps as part of a group from The Summer School at Les Houches . The rest of this post will take a closer look at the trip he made, originally documented in Roy Glauber’s Physics Today article from 2002 . Some of the photos Glauber took during that trip did not make it into the original article, but they do appear here.

Before we dive into the trip itself, let’s cover some background. The Summer School at Les Houches was founded by Cécile DeWitt-Morette in 1951, when she was 29 years old, partially inspired by her experience with Girl Scouts and the Ann Arbor Summer Symposium at the University of Michigan. Many attendees were already Nobel Laureates or later went on to win Nobel Prizes in Physics. Dewitt-Morette led the school until 1972, which annually awards its Cécile DeWitt-Morette, Ecole de Physique des Houches Prize to scientists under age 55 who have made a remarkable contribution to physics AND have attended the school. Les Houches School of Physics is still going strong today.

In 2007, Cécile DeWitt-Morette was inducted into the French Legion of Honor for her work. Upon her death, Gian Francesco Giudice, head of the Theoretical Physics Department at CERN, said, “she will always be remembered for her vision in creating the school at Les Houches, which shook the postwar world of European physics, revolutionizing the way of teaching science and filling the gap between the people working at the frontier of research and the young scientists entering the field. For 22 years Cécile directed the Les Houches School, whose success remains her lasting legacy.” Her papers reside at UT Austin and document her career as a mathematical physicist.

And now, to Enrico Fermi’s Alpine excursion.

During the the break in classes for le quatorze juillet (literally, the 14th of July or Bastille Day) holiday in France, Cécile DeWitt-Morette scheduled an excursion for some of the students. She arranged for an invitation to visit the cosmic-ray laboratory at the top of the Mont Blanc Massif in the French Alps where temperatures at the peak are well below freezing even in the height of summer. Thus, Enrico Fermi, Léon van Hove, Afaf Sabry, and Roy Glauber began their epic journey to the École Polytechnique Cosmic Ray Laboratory near the peak of Aiguille du Midi in the French Alps. The only issue with this journey? Construction of the cable cars to the summit was not fully finished until 1955, a year after this expedition. What is now two trips in cabled cars was then four separate shorter journeys . Our brave physicists had to make their way up 12,605 feet on the make-do cabled conveyances used by construction workers to move material that were called “bennes,” which Glauber likens to steel buckets. When the cable cars were completed, they held the record for the world’s highest cable car until the 1970s.

Photographer and Nobel Prize winning physicist Roy Glauber described this harrowing cable car trip in his 2002 Physics Today article:

“We arrived at the foot of the mountain in the early afternoon and were not altogether surprised to be asked by an attendant to sign accident indemnity waivers before boarding the first of our four conveyances. It was the decaying remains of a cable car that must have been run for tourists generations earlier. Fermi gazed heavenward and hoped out loud that the cable was in better shape than the car.”

“The next stage of our ascent was much more exposed and exciting. It required us to sit on what was little more than a broad plank suspended from the cable wheels by simple hooks at both ends. Someone was providentially awaiting us on the wooden platform to which the plank transported us. His task was to give us instructions for the next two stages, in which we were to travel in bennes. Properly translated, bennes means buckets; these were in fact shallow steel bins, also suspended from the cable wheels by two simple hooks.”

“Our benne seemed sturdier than the plank we had ridden earlier and, squeezed together in it we soon rose into a dense layer of stratus cloud. We were engulfed by glaring white fog and our world closed in to the benne beneath us and the squeaking of the wheels, unseen above us. Fermi smiled archly, saying he understood now how angels felt. He began singing the only hymn he knew: “Mine eyes have seen the glory… .” We all joined the chorus, “Glory, glory, hallelujah. …” It took only one repeat of the chorus to bring us out into clear daylight and our approach to the next platform, which projected from a cliff, well above the clouds.”

Glauber admits that after the trip up the mountain, the laboratory tour at the top of the mountain was relatively anticlimactic. He merely notes that they were led on a 15-minute hike through the snow to a cabin with cloud chamber equipment inside. However, “the cabin was warm, its veranda commanded an incredible view, and a glass of mulled wine at that altitude is a heady experience.” Indeed! Seems like it was worth the trip!