Tuesday, February 20, 2007

Killer Asteroid Politics

This past weekend, a group of scientists and former astronauts met in San Francisco to discuss the possibilities for averting disaster if one of the hundreds of known potentially hazardous asteroids were found to be on a collision course with the Earth. They were motivated, in part, by the recent discovery that one such asteroid -- known as "99942 Apophis" -- will skim very close to the Earth in 2029, and has a significant chance of actually hitting the Earth seven years later. The central question is: if precise observations during the 2029 passage reveal that Apophis will hit in 2036, what should we do about it?

You might think that these astronomers are just being alarmist. After all, there have been several recent occasions when the news media report on an asteroid that might hit the Earth -- only to retract the claim a few days later, after additional observations rule out a collision. The primary source of these reports is a list maintained by the Minor Planet Center at the Harvard- Smithsonian Center for Astrophysics. Consider the position of the scientists. They are certainly aware that additional observations will often rule out a future impact -- but if they withhold the early predictions they are accused of a cover-up. So instead they update their predictions continuously, the newspapers report on an uncertain impact, and the astronomers are accused of fear-mongering. It's a no-win situation.

Considering the possible consequences of an asteroid impact, I would rather know about it as far ahead of time as possible. It's similar to the early predictions by meteorologists tracking the path of a hurricane. The uncertainties grow larger as they extrapolate the observations further from the storm's current location -- but the advance warning helps residents of the potentially affected areas to begin preparing for the worst. In the case of Apophis, this might mean placing the entire planet on alert, but at least we would have seven years to devise and execute a plan for avoiding doomsday.

The age of the dinosaurs came to a sudden end when a large asteroid struck near the Yucatan peninsula in the Gulf of Mexico. If humans are smart enough, we can avoid a similar fate.

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