Fine Tuning Celestial Mechanics
2 Aug 2002
(Source: West Virginia University)
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firstname.lastname@example.org A West Virginia University chemist and five other researchers have taken a quantum leap in predicting the orbits of celestial bodies, research that could one day help scientists accurately foretell if an asteroid or comet is headed for Earth. Charles Jaffe, associate professor of chemistry at WVU, is part of a team that combined a near 70-year-old chemical transition state theory and celestial mechanics to predict the outcome of a simulation involving Martian asteroids. "We wanted to test the application of transition state theory to celestial mechanics by comparing our results with those of a simulation," Dr. Jaffe said. "We chose as our simulation the escape of asteroids from Mars because of our interest in the Martian meteor found in Antarctica a few years ago." The research team's paper, "Statistical Theory of Asteroid Escape Rates," made the cover of the July 2 issue of Physical Review Letters. The paper is also featured on the Physical Review Focus Web site at http://focus.aps.org./v9/st31.html Co-authors were David Farrelly, a chemist at Utah State University; T. Uzer, an atomic physicist at Georgia Institute of Technology; Jerrold Marsden, a mathematician at California Institute of Technology, and Shane D. Ross, his student; and Martin W. Lo, a software developer with Cal Tech's Jet Propulsion Laboratory. Transition state theory, developed by chemists in the 1930s, establishes a brief stage in chemical reactions between reactant and product, said Jaffe, who has helped refine the theory for modern uses. Bottlenecks between orbits of celestial bodies resemble transition states in chemistry, he added. For their research, Jaffe and his fellow scientists developed a computer-based simulation of asteroids orbiting Mars, then used the transition state theory to predict how many asteroids would remain in the red planet's orbit and how many would escape. The team then calculated the survival and escape rates by performing the simulation 107,000 times to represent the asteroids' trajectories. There was a 1 percent difference between the simulation's results and the theory's predictions. "This means the theory works and you don't need to run the simulations, which take several days," said Jaffe, who came to WVU in 1984 after obtaining his doctorate from the University of Colorado and doing postdoctoral work at the University of Toronto and Columbia University. Extending transition state theory to celestial mechanics could one day help scientists better predict such outer space events as asteroids and comets headed for Earth and solar storms capable of disrupting satellite communications, Jaffe said. Astronomers announced recently that they are monitoring a recently discovered asteroid that has a minimal chance of striking the Earth in 2019. Last month, scientists discovered an asteroid that narrowly missed the planet -- after it passed by. Using transition theory, Jaffe explained, scientists could determine which group of asteroids is more likely to come close to Earth. "What this will do is help us decide which space matter is worth worrying about," he said. "There is not enough time to look at each asteroid. Using transition state theory, instead of looking at individual things, one can look at classes of things." The research is supported by the National Science Foundation, American Chemical Society, West Virginia NASA Space Grant Program and NASA-ASEE Summer Faculty Fellowship.