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The day the Earth was not threatened by an asteroid
Astronomers almost alerted Bush to doomsday fears
Carl T. Hall, Chronicle Science Writer
Thursday, February 26, 2004
A killer asteroid didn't collide with Earth last month. But panicky astronomers came mighty close to waking up President Bush with a nasty message that a collision was imminent.
During a scientific meeting on near-Earth objects under way in Southern California this week, astronomers revealed that they seriously contemplated alerting top NASA officials -- and ultimately the White House -- to the possibility that a space rock was hours away from hitting Earth in mid-January.
It was a doomsday scenario worthy of Hollywood that quickly fizzled out: Further observations showed the initial rough calculation of the asteroid's size and location were way off, and it passed harmlessly into distant space. But experts said the incident and how it was handled highlighted gaps in the system used to monitor Earth's neighborhood for potentially dangerous moving objects.
Some software fixes already have been made to reduce the chance of more false alarms. Scientists also have suggested that an international authority be designated to handle such issues as notifying governments, alerting the public and analyzing evidence in emergency situations.
Clark Chapman, a planetary scientist at the Southwest Research Institute in Colorado who summarized the incident in a presentation Monday at the scientific meeting, said he could not find any major fault with how the situation was handled.
However, he suggested the decisions were far too rushed -- and the whole process far too ad hoc -- considering the stakes. "When you're talking about defending the planet, I think there ought to be more forethought," he said during a telephone interview from the conference.
The adventure started the night of Jan. 13, when a robotic observation program in New Mexico picked up what appeared to be a small moving object that no one had seen before.
Four quick images of the object were relayed to the International Astronomical Union's Minor Planet Center in Cambridge, Mass., about half a day after the initial find. Researcher Tim Spahr fed the details into a computer, choosing from hundreds of possible trajectories the one path that seemed to best fit the scanty data.
Following standard procedures, he posted the object and its path on a public Web site so other astronomers could start tracking it. Then he went to dinner -- unaware that he had put Earth in the center of a big bull's-eye.
Brian Marsden, director of the Minor Planet Center, said the purpose of the initial posting is solely to guide observers, adding that the first images of the object were not spaced far enough apart to accurately predict where it was headed.
Within an hour of the first public notice, an amateur astronomer in Europe, identified as Reiner Stoss, "noticed a curiosity," as Chapman put it in his written account: The data showed the newfound object would get 40 times brighter within the next day alone, suggesting it would be six times closer to the Earth.
That meant a collision was imminent -- a bit of information Stoss deemed worthy of sharing with a few colleagues in an Internet chat room.
As the minutes ticked by, other astronomers started to take notice, including Chapman and asteroid tracker David Morrison of NASA's Ames Research Center in Mountain View. They consulted with other experts at NASA's Jet Propulsion Laboratory in Pasadena.
Chapman describes a frantic evening and early morning, as scientists simultaneously scrambled to track down colleagues, gather more data and use what little information they had to plot the asteroid's course.
Marsden promptly revised the original posting to have the asteroid moving away from Earth. Later that night, after returning from dinner and logging on to his computer at home, Spahr would also revise his posting, this time showing the object coming toward Earth but narrowly missing the planet.
Little wonder the scientists were keen to redo their numbers. As Chapman recounted the events, the Minor Planet Center "faced the embarrassing fact that they had effectively made the first-ever prediction of a near-term asteroid impact without even realizing it themselves."
Late the night of Jan. 14, JPL's Steve Chesley calculated about a 1-in-4 chance that the newfound asteroid was indeed about to slam into the Earth.
Such a scenario would not have ended life as we know it because of the small size of the asteroid, judged initially to be about 30 meters across, about half the size of the asteroid that famously pulverized a remote area in Siberia in 1908, but a mere pebble compared with prehistoric impacts. Just how big a bang it might have made would depend on many factors, including the composition of the object: whether it was solid or a collection of loose rubble.
Nobody knew at the time just how big the object was, but Chapman said scientists were considering the possibility of "the biggest atmospheric explosion of many decades on planet Earth," enough to break windows and "knock down weak houses" over a large area if it were to happen over a populated land area, or to generate a devastating tsunami if it hit over an ocean.
Chapman said he never contemplated telephoning the White House directly. However, the astronomers were well aware that President Bush happened to be scheduled to appear at NASA the very next day to unveil his plans for a new manned mission to Mars and the moon.
E-mail Carl Hall at chall@sfchronicle.com.
The day the Earth was not threatened by an asteroid
Astronomers almost alerted Bush to doomsday fears
Carl T. Hall, Chronicle Science Writer
Thursday, February 26, 2004
A killer asteroid didn't collide with Earth last month. But panicky astronomers came mighty close to waking up President Bush with a nasty message that a collision was imminent.
During a scientific meeting on near-Earth objects under way in Southern California this week, astronomers revealed that they seriously contemplated alerting top NASA officials -- and ultimately the White House -- to the possibility that a space rock was hours away from hitting Earth in mid-January.
It was a doomsday scenario worthy of Hollywood that quickly fizzled out: Further observations showed the initial rough calculation of the asteroid's size and location were way off, and it passed harmlessly into distant space. But experts said the incident and how it was handled highlighted gaps in the system used to monitor Earth's neighborhood for potentially dangerous moving objects.
Some software fixes already have been made to reduce the chance of more false alarms. Scientists also have suggested that an international authority be designated to handle such issues as notifying governments, alerting the public and analyzing evidence in emergency situations.
Clark Chapman, a planetary scientist at the Southwest Research Institute in Colorado who summarized the incident in a presentation Monday at the scientific meeting, said he could not find any major fault with how the situation was handled.
However, he suggested the decisions were far too rushed -- and the whole process far too ad hoc -- considering the stakes. "When you're talking about defending the planet, I think there ought to be more forethought," he said during a telephone interview from the conference.
The adventure started the night of Jan. 13, when a robotic observation program in New Mexico picked up what appeared to be a small moving object that no one had seen before.
Four quick images of the object were relayed to the International Astronomical Union's Minor Planet Center in Cambridge, Mass., about half a day after the initial find. Researcher Tim Spahr fed the details into a computer, choosing from hundreds of possible trajectories the one path that seemed to best fit the scanty data.
Following standard procedures, he posted the object and its path on a public Web site so other astronomers could start tracking it. Then he went to dinner -- unaware that he had put Earth in the center of a big bull's-eye.
Brian Marsden, director of the Minor Planet Center, said the purpose of the initial posting is solely to guide observers, adding that the first images of the object were not spaced far enough apart to accurately predict where it was headed.
Within an hour of the first public notice, an amateur astronomer in Europe, identified as Reiner Stoss, "noticed a curiosity," as Chapman put it in his written account: The data showed the newfound object would get 40 times brighter within the next day alone, suggesting it would be six times closer to the Earth.
That meant a collision was imminent -- a bit of information Stoss deemed worthy of sharing with a few colleagues in an Internet chat room.
As the minutes ticked by, other astronomers started to take notice, including Chapman and asteroid tracker David Morrison of NASA's Ames Research Center in Mountain View. They consulted with other experts at NASA's Jet Propulsion Laboratory in Pasadena.
Chapman describes a frantic evening and early morning, as scientists simultaneously scrambled to track down colleagues, gather more data and use what little information they had to plot the asteroid's course.
Marsden promptly revised the original posting to have the asteroid moving away from Earth. Later that night, after returning from dinner and logging on to his computer at home, Spahr would also revise his posting, this time showing the object coming toward Earth but narrowly missing the planet.
Little wonder the scientists were keen to redo their numbers. As Chapman recounted the events, the Minor Planet Center "faced the embarrassing fact that they had effectively made the first-ever prediction of a near-term asteroid impact without even realizing it themselves."
Late the night of Jan. 14, JPL's Steve Chesley calculated about a 1-in-4 chance that the newfound asteroid was indeed about to slam into the Earth.
Such a scenario would not have ended life as we know it because of the small size of the asteroid, judged initially to be about 30 meters across, about half the size of the asteroid that famously pulverized a remote area in Siberia in 1908, but a mere pebble compared with prehistoric impacts. Just how big a bang it might have made would depend on many factors, including the composition of the object: whether it was solid or a collection of loose rubble.
Nobody knew at the time just how big the object was, but Chapman said scientists were considering the possibility of "the biggest atmospheric explosion of many decades on planet Earth," enough to break windows and "knock down weak houses" over a large area if it were to happen over a populated land area, or to generate a devastating tsunami if it hit over an ocean.
Chapman said he never contemplated telephoning the White House directly. However, the astronomers were well aware that President Bush happened to be scheduled to appear at NASA the very next day to unveil his plans for a new manned mission to Mars and the moon.
E-mail Carl Hall at chall@sfchronicle.com.
