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James B. Pollack (1938–1994)

Published onSep 01, 1994
James B. Pollack (1938–1994)

James B. Pollack was born July 9,1938, in New York City. He died June 13, 1994 of Chordoma, a rare form of cancer. His parents, Jeanne and Michael Pollack, ran a family clothing business, Pollack's, that had been in operation since the turn of the century. When Jim was very young, his parents and teachers worried that he might be retarded! Fortunately, according to his sister Ginny Breslauer of Woodmere, N.Y., a psychologist recognized that he thought so fast that his verbalization got in trouble trying to keep up! Jim taught himself to speak slowly to keep the words on track, and was, in fact, a slow speaker throughout his life (and impossible to interrupt). He became an avid young "rocket scientist" in the basement of his family home, was a track star and valedictorian for Lawrence High School, and Phi Beta Kappa at Princeton, where he graduated with High Honors in Physics. At Princeton, he was on the staff of "The Tiger" — the college humor magazine. Jim always enjoyed a good laugh, even at his own expense. In his 1987 Ames Fellow Award formal presentation dinner, he was soundly roasted by his colleagues in the Space Science Division, and loved every minute of it.

After obtaining a Masters degree at Berkeley in nuclear physics, Jim went to Harvard to study Astronomy where he met Carl Sagan. Sagan realized Jim's talents immediately, calling him "bright and thoroughly imaginative, with keen physical insight and a significant ability to choose the most felicitous approaches to complex problems in mathematical physics". Sagan further noted that Jim " ... is interested in a wide variety of astronomical problems and has a significant capability for hard work." Even over thirty years, some things don't change! In 1970, Jim was lured to Ames by Ray Reynolds. Jim's work at Ames was quite diverse, and consisted of numerical modeling of planetary processes, planning and analysis of spacecraft data, and planning and interpreting observations from Ames' Kuiper Airbome Observatory. For example, he modeled KAO observations to determine the composition of the Venus clouds, the composition of Mars surface soils and atmospheric dust, and the size of the grains on Saturn's ring particles. He played key roles in nearly every NASA planetary mission since Apollo, including Mariner 9, Viking, Voyager, Pioneer Venus, Mars Observer, and Galileo. In all of his theoretical work, he blended extensive use of exact, numerically intensive techniques with intense flashes of "keen physical insight".

With Ray Reynolds and other collaborators, Jim created the first detailed models of the early stages of formation of the giant gas planets. These models were the first to treat the forming planets like small stars, and to make accurate predictions as to the large amounts of energy they emitted as they collected infalling gas and solid material. Jim and his team used the models to explain the different compositions of the moons of Jupiter — the inner moons were too close to the hot, glowing gas spheres to allow icy material to freeze out and remain primarily rock to this day.

Jim used these models to study the Saturn system as well; this work, and his deep understanding of scattering of radiation by wavelength-sized particles, led him to be the first to resolve a real puzzle posed by Saturn's rings. They gave off no radio wave emission, but were strong radar reflectors. Strange suggestions, such as metallic particles, were being advanced by others, but Jim realized that normal water ice particles could have this behavior if they were in the proper size range — centimeters to meters in size. He and Jeff Cuzzi refined these ideas into predictions that were confirmed by Voyager observations.

Over the years, Jim and Bob Haberle developed the world's most complete model of Mars' atmospheric circulation. The model was used to interpret Viking spacecraft data and is also helping plan future missions to Mars by NASA as well as by the European and Russian space agencies. It has produced an understanding of the winds and pressure patterns seen by Viking, as well as leading towards explanations for the cause of the giant dust storms seen on Mars.

Jim laid the foundation for the study of evolutionary climate change on all the terrestrial planets including Earth. This endeavor is so large in scope that only the outlines of its methodology are in place today; for example, Jim was the architect of two separate studies of Mars and Venus, still ongoing, that model the coupled evolution of the crust and atmosphere of a planet. These models, developed with Jim Kasting, include outgassing by the molten crust, atmospheric chemistry and radiative transfer, greenhouse effect, and reabsorption of atmospheric constituents in surface mineralogy.

Jim's planetary perspective led him to make significant early contributions to the evolution of the Earth's atmosphere itself. With Brian Toon, Chris McKay, and other collaborators, he studied the effects on Earth's atmosphere and surface biology of the giant asteroid impact that led to the extinction of the dinosaurs, due to the insulating effect of the debris lofted into the atmosphere. This work led others, with Jim as collaborator, to the studies of "nuclear winter" which became influential to the national agenda on nuclear weapons. Jim also made important early contributions to our growing understanding that volcanoes can produce significant effects on the climate of the Earth.

Jim's scientific quest always led him closer to the origin of the planets he studied, and of their atmospheres. In recent years, as astronomical observations began to return useful data on forming planetary systems possibly much like our own, his research had turned increasingly towards studies of the properties of planet-forming systems. With Pat Cassen, Bill Cabot, and others, he made use of state of the art computational fluid dynamical models on Ames supercomputers to study turbulent convection in gaseous protoplanetary disks. He also applied his radiative transfer expertise to determining the infrared and millimeter wavelength emission of their dusty gases.

Pollack's broad perspective and highly creative interdisciplinary research brought him many awards. He won the prestigious Gerard P. Kuiper Prize of the Division of Planetary Sciences of the American Astronomical Society "for excellent and enduring contributions to planetary science". He was the co-recipient of the Leo Szilard Award of the American Physical Society for research in the public interest and an elected Fellow of the American Geophysical Union, the American Association for the Advancement of Science, and the American Astronautical Society. He won the Arthur S. Flemming Award, several NASA medals for Exceptional Scientific Achievement, and the Space Science Award of the American Institute of Aeronautics and Astronautics for his work on planetary atmospheres, surfaces, and climate. He won Ames' H. Julian Allen award twice, and was elected both Ames Associate Fellow and Ames Fellow.

Away from work, Jim enjoyed tennis and science fiction, and, although not fast, he was said to be a highly accurate shooter in basketball. He was an avid opera fan and a steady subscriber to the San Francisco opera. He brought to this avocation the same all embracing intellectual curiosity that he applied to his scientific pursuits. Thus, while he liked operas of every style and period, he was particularly attracted to those that were new or rarely performed, which gave him an opportunity to study new musical and historical contexts. Jim's longtime friend Bruce Hassell, who was his unfailing support during his illness, says Jim was especially fond of Wagner in any and all forms. Turandot, a story of suitors and riddles in an oriental setting, was a special favorite of Jim's. Susan Mead, another Ames opera buff, recalls that Jim would radiate sheer delight for days after seeing a good performance — which led some of his coworkers to name one of the local workstations "Tosca."

All those who worked with Jim can testify to his encyclopedic grasp of properties and processes of importance to the origin, evolution, and current state of our solar system and others. We can also testify to his dogged persistence and unswerving devotion to answering the riddles of our solar system. We quickly learned that, if we couldn't explain an idea to Jim, we didn't understand it, and it was probably wrong. His penetrating questions were a familiar and recurrent feature at scientific meetings. He was, in Sagan's words, " … a gifted and inspiring teacher" and role model, mentoring dozens of scientists now doing leading research at Ames and around the world. His illness sapped his strength but didn't touch his intelligence or motivation, and he tirelessly continued working on the planning of future missions to Saturn, Mars, and Venus to the very end. He had many close, long-term friends, with whom he maintained lifelong relationships and whom he was never too busy to help out when needed. We at Ames, and in the scientific community, will miss him greatly.

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