On April 6–9, 1987, a special symposium was held in Brussels in honor of Marcel Nicolet on his 75th birthday. The symposium was entitled “On the Diversity and Similarity of Comets” and was cosponsored by the Institut d'Aeronomie Spatiale de Belgique and the European Space Agency (ESA). Nearly 200 scientists participated; the proceedings will be published by ESA.
Nicolet is a world-renowned scientist who has made far-reaching contributions to the understanding of the chemistry and dynamics of the upper atmosphere. In his first years as a scientist, he carried out important research on comets. He was one of the initial planners of the International Geophysical Year (IGY) and served as the Scientific Secretary of the Comité Spéciale de l'Année Géophysique Internationale (CSAGI). Nicolet deserves much of the credit for the success of the IGY. He has been a member of AGU since 1959 and was awarded the Bowie Medal in 1984.