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

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

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.