W. Reid Thompson, Senior Research Associate in the Laboratory for Planetary Studies at Cornell University, died on 22 April 1996, at age 44, after a long and courageous fight with metastatic lung cancer. Thompson, who first came to Cornell as a graduate student in biophysical chemistry, entered planetary science when the opportunities to investigate organic chemistry in the outer Solar System were just beginning to blossom. Throughout his career, he was known for bringing an extraordinary array of abilities to his research, with expertise ranging from laboratory inorganic chemistry to numerical radiative transfer calculations to spacecraft image processing.
Scientifically, Reid was perhaps best known for a series of papers on the organic chemistry of the atmosphere and haze layer of Titan, demonstrating that the gas-phase and solid products produced in laboratory simulations provided excellent matches to spacecraft observations. Reid later extended this work to the atmospheric chemistry of the giant outer planets, and to the radiation chemistry of carbon-containing ices in the outer Solar System. His subsequent work on cometary impacts on Titan suggested that much of the moon's surface should have experienced liquid water within transient crater lakes, inside of which further reactions relevant to prebiotic organic chemistry may have occurred.
Employing a very different set of skills, Reid created a widely reproduced sequence of images of the Earth taken by the Galileo spacecraft during its 1990 and 1992 flybys. These images showed subtle differences in the types and conditions of growing vegetation, in the properties of Antarctic ice, and in the water vapor contents of clouds. Reid had initially developed his image processing skills as an associate imaging team member of the Voyager Uranus and Neptune flybys and for Galileo.
Reid grew up on his family's farm in Mackville, Kentucky. He was Salutatorian of Washington County High School in 1969, and graduated with an array of awards in chemistry and a BS with High Distinction from the University of Kentucky in 1973. He came to Cornell as a National Science Foundation Fellow, and received his MS in biophysical chemistry in 1975, winning the distinguished teaching awards of the Department of Chemistry and of the College of Arts and Sciences. Reid then transferred into Astronomy and Space Sciences, where he earned his PhD in 1984, working with Carl Sagan. Reid was associated with Sagan's Laboratory for Planetary Studies for the rest of his career. In that lab, Reid served as a scientific mentor to a succession of undergraduate and graduate research assistants. Not long before his own death, Carl wrote an obituary for Reid (Icarus 123, 2-3, 1996), in which he described Reid as "gentle, kind, and brilliant."
Reid was the youngest child of Marvin and Dorothy Raybourne Thompson. He is survived by his mother, his daughter Alexis Lyn, his brother Pete Thompson, two sisters, Betty Haydon and Jackie Sutton, and his fiancée Denise Weldon. A scholarship in his memory has been established at Washington County High School in Springfield, Kentucky.
Reid's approach to his final illness exemplified his remarkable energy and breadth of knowledge. He researched his disease intensively, enjoying the support volunteered by graduate students in the department of astronomy. His knowledge of the primary medical literature on his illness often surprised his doctors, and at times led to novel treatment strategies which more than likely prolonged his life. Throughout it all, Reid retained his enthusiasm for understanding the world, his optimism, and his well-known warmth and generosity towards his acquaintances, friends, and family.
Photo (available in PDF version) courtesy Denise Weldon.