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VOLUME 5, No:23 The Scientist November 25, 1991 People 1991 Kyoto Prizes Recognize Advances In Deterministic Chaos, Polymer Science Author: Rebecca Andrews, p.21 At about $300,000 each, the international Kyoto Prizes are among the most lucrative cash awards given in science or the arts. These prizes, sponsored by the Inamori Foundation of Japan in three categories each year--advanced technology, basic sciences, and creative arts and moral sciences--were presented at a ceremony in Kyoto two weeks ago. Edward N. Lorenz, professor emeritus at the Massachusetts Institute of Technology, won the prize in basic sciences in part for his contributions to the theory of deterministic chaos, a principle that has profoundly influenced a wide range of sciences. Michael Szwarc, a senior fellow at the Loker Hydrocarbon Research Institute at the University of Southern California, won the advanced technology award for his pioneering work in polymer science. Lorenz, a meteorologist, was cited for establishing "the theoretical basis of weather and climate predictability, as well as the basis for computer-aided atmospheric physics and meteorology." The citation goes on to say that Lorenz "made his boldest scientific achievement in discovering `deterministic chaos,' a principle which has profoundly influenced a wide range of basic sciences and brought about one of the most dramatic changes in mankind's view of nature since Sir Isaac Newton." Lorenz says that while he was always interested in the weather, he didn't decide to pursue a career in meteorology until World War II, when he took a course qualifying him to serve as a weather forecaster. "Prior to that I had been planning to be a mathematician," says Lorenz. "At the end of the war, I decided to stay with meteorology." Lorenz didn't turn his back on his first interest, however. "Most of the work I've done in meteorology was very mathematically oriented." And while he says his research has not called for "the deep knowledge that professional mathematicians really use," he points out that his work does display "a fondness for mathematics." This fondness is clearly exhibited in Lorenz's theoretical work on the general circulation of the earth's atmosphere. In 1955, Lorenz introduced the concept of "available potential energy," essential to the computer prediction of atmospheric changes based on the laws of physics. This concept, says Lorenz, is a measure of the availability of the reservoir of potential energy in the earth's atmosphere for conversion to the energy that powers the circulation system driving weather and climate. The energy is stored as heat and gravitational potential--for example, atmospheric moisture waiting to fall as precipitation. In 1960, he introduced a method for describing atmospheric general circulation using a minimal set of mathematical equations in computer simulation. He brought this work together in The Nature and Theory of the General Circulation of the Atmosphere, published in 1967 by the World Meteorological Organization of Geneva; the book remains a classic. During the course of this work, in the late 1950s, Lorenz found himself searching for a system of equations that he could use to try out his ideas. He says that he needed to find a set of equations that were not periodic--"like the weather is not periodic." What he found was that very small changes in the equations led to very big differences in the latter part of the solution, giving the appearance of chaos. This led to Lorenz's formulation of the theory of deterministic chaos, which he explains as describing "something whose behavior from one time to the next is not random, but looks random" (Journal of Atmospheric Sciences, 20:130-41, 1963). This theory--and subsequent research by Lorenz--has had profound implications in meteorology and weather prediction. According to Lorenz's research, it is theoretically impossible to avoid some degree of uncertainty in setting the initial values used in computer modeling of the weather. This inherent uncertainty limits accurate prediction of certain aspects of the weather to about two weeks, says Lorenz, since, according to the precepts of deterministic chaos, minor, undetectable discrepancies will lead to huge differences later on. The idea that a tiny, indiscernible occurrence can lead to vast changes farther down the line has been coined "the butterfly effect," says Lorenz, because it implies that something as inconsequential as the flap of a butterfly's wings could theoretically affect the weather somewhere in the world. When asked whether a butterfly could really have such influence, Lorenz says that while "it hasn't been disproved," the literal effect of a butterfly's wings will have to remain in the realm of the theoretical: "We could never detect it if it did matter, because there are so many other butterflies flapping their wings, and so many other creatures with much greater effects." As a result of this work, says Lorenz, people have begun to send him references to butterflies in the context of chaos theory. One example is "The Sound of Thunder," a short story by Ray Bradbury in which the death of a prehistoric butterfly affects a modern presidential election. In his current work, Lorenz is looking at several sides of chaos theory, as well as trying to assess the predictability of various aspects of the weather. Lorenz, 74, earned his master's degree in mathematics from Harvard University in 1940. After serving in World War II, he attended MIT, where he earned a doctoral degree in meteorology in 1948. He remained at MIT for his entire career. After serving on the research staff of the department of meteorology for several years, he was appointed to the faculty as an assistant professor in 1955. He was promoted to professor in 1962, and became a professor emeritus in 1987. Lorenz has won numerous awards, including the Crafoord Prize from the Royal Swedish Academy of Sciences in 1983. Michael Szwarc, winner of the Kyoto Prize for advanced technology, was recognized for fundamental contributions to polymer science. The award citation credits Szwarc with "paving the way for new functional materials with indispensable applications in advanced technology, and providing many scientists and engineers . . . with significant and unprecedented methodologies for the design and synthesis of new polymeric materials." Szwarc discovered living polymerization, a reaction that allows the resultant polymers to maintain chain-end reactivity even after completion of the reaction (Nature, 178:1168-69, 1956). This advance allows the synthesis of polymers with controlled molecular weights, and with functional groups placed at particular positions in the polymer chain. An example of an "end-functionalized polymer"--created by a living polymerization reaction--is the liquid rubbers used in some industrial applications. Before Szwarc's discovery, this precise control of polymer synthesis was impossible, creating a serious obstacle to the development of advanced polymeric materials. Szwarc also made fundamental contributions to the development of "block polymers," in which two or more different polymer chains are connected to each other through chemical bonds by the sequential addition of monomers to living polymers. This has led to the manufacture of a variety of unique polymeric materials, such as thermoplastic elastomers. Szwarc, 82, was born in Poland. He earned a Ph.D. in organic chemistry in 1945 at Hebrew University in Israel, and a D.Sc. in physical chemistry in 1949 at the University of Manchester, England. He joined the faculty of the State University of New York's College of Environmental Science and Forestry, Syracuse, in 1953, where he was also director of SUNY's Polymer Research Center. After his retirement in 1979, he joined the Loker Hydrocarbon Research Institute at USC. Although Szwarc is no longer actively involved in research, he is still completing some writing projects, including articles and a book on ionic polymerization. The third Kyoto Prize winner, in the category of creative arts and moral sciences, was Peter Stephen Paul Brook, a British stage director. The prizes, which consist of a gold medal, a certificate of recognition, and 45 million Japanese yen, were first awarded in 1985. --Rebecca Andrews