Asteroid False Alarm Shows Limits of Alert Systems

Stefan Lovgren
for National Geographic News
March 8, 2004

It was 5:15 p.m. on January 13 when Timothy Spahr received the daily batch of observations from the Lincoln Near-Earth Asteroid Research (LINEAR) telescope in Socorro, New Mexico. The telescope searches the skies for new asteroids.

Spahr, an astronomer at the Minor Planet Center at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, was heading out for dinner with a colleague visiting from Hawaii. He quickly sifted through the data.

Out of the thousands of observations, he was unable to identify five objects. Nothing uncommon. As usual, Spahr calculated possible orbits for the objects and posted his results on a Web site, so that other scientists could confirm the location of the asteroids. Then he left for the day.

What Spahr didn't realize was that for one of the five objects, he projected an orbit that showed a direct impact with Earth the next day.

Soon, Internet message boards were buzzing. At NASA's Jet Propulsion Laboratory in Pasadena, California, a senior engineer predicted that the approaching asteroid, named 2004 AS1, had a 25 percent chance of crashing into Earth somewhere in the Northern Hemisphere in the next 36 hours.

As cloudy weather complicated further observations, one veteran asteroid researcher, Clark Chapman of the Southwest Research Institute in Boulder, Colorado, proposed calling the President of the United States with the news.

It's a good thing he didn't. As it turns out, the data was incomplete. The closest 2004 AS1 ever got to Earth was about 8 million miles (13 million kilometers), sometime in mid-February.

The scare was the latest in a series of false alarms that highlights the apparent lack of procedure for dealing with a possible asteroid threat. Several astronomers complained they did not know whom to call in an emergency.

Last Tuesday, Lindley Johnson, a program scientist at NASA's Near-Earth Object Observation Program in Washington, D.C., sent a memo to a select group of asteroid experts. Should a potential impactor be detected, Johnson wrote, "You call me."

Very well. But what happens next? There is no government agency assigned to "protect the Earth." In theory, if Johnson's office is warned of an asteroid threat, the office would pass it along the chain of command to the NASA administrator, who would contact the President.

"What happens after that? Quite frankly, I don't think anybody knows," said Brian Marsden, director of the Minor Planet Center. "There is no master plan in place."

Incomplete Data

Continued on Next Page >>




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