Supercomputer Simulates Comet Impact In 3D
(From the July/August 1997 issue of StarDate magazine)
Scientists at Sandia National Laboratories recently tested the power of the world's fastest supercomputer by running the first high-resolution, three-dimensional simulation of a comet impact into one of Earth's oceans. Though the prospects for humanity haven't improved according to the results, the simulation demonstrates the expanding role supercomputers will play in predicting what separates a regional catastrophe from a global catastrophe.
The simulation ran on a new supercomputer capable of making one trillion calculations a second with the same initial conditions -- size, velocity, density and composition -- used for a simulation of the Shoemaker-Levy 9 comet impacts on Jupiter that ran at Sandia in 1994.
"People have looked at ocean impacts, but there's been no in-depth computational modeling," project scientist David Crawford says. "With this class of machine, we are finally at the point of being able to do meaningful 3D simulations."
Past simulations of ocean, as well as land, impacts have been limited to two-dimensional modeling, Crawford says, which can skew the results. A two-dimensional model requires a vertical imcoming trajectory, an unlikely scenario, Crawford says. The Sandia simulation depicts one of the most statistically likely impacts: a relatively small, one-kilometer comet striking one of Earth's oceans at a 45-degree angle. Such an event may occur at least every half a million years.
The results of the impact, according to the simulation, are phenomenal. Between 300 and 500 cubic kilometers of ocean are vaporized on impact along with the comet itself. Water that isn't vaporized forms a tsunami that could be as high as 100 meters tall 1000 kilometers from the impact. -- Doug Addison
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