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How We Knew AL00667 Would Miss Earth
jefu writes "In January there seems to have been an incident in which it was thought that an object (asteroid) in space might have hit the earth within a couple of days of being spotted. It did miss, though. This story (from NASA/Ames) talks about the discovery of the object and the process that astronomers went through to determine if the asteroid was or was not a threat."
Most all missle defense proposals depend on punching a hole in an ICBM by heating it. For all their destructive potential, ICBMs are 90% thin skinned gas tank. You could take one out with a grenade, if you could somehow get it there.
The power required to destroy any rock big enough to survive atmospheric entry would be orders of magnitude greater.
"Faith: Belief without evidence in what is told by one who speaks without knowledge, of things without parallel." - A.B.
Short Warning Times
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Article Posted: February 19, 2004
By: David Morrison
For the story of AL00667, which briefly masqueraded as an asteroid that would hit the Earth within two days of its discovery, read on.
February 19, 2004 Short Warning Times
Following is information on the small asteroid known last January 13-14 as AL00667. A preliminary analysis of the discovery data for this object yielded a possible impact with Earth in less than 2 days time -- a situation not encountered previously in the Spaceguard Program. Although we knew at the time that such a prediction of imminent impact was improbable, a collision could not be ruled out. And if a possibility of an impact in 2 days existed, what should we do about notifying governments or the public? The story of this situation on January 13, 2004, is included as part of a paper by Clark Chapman (Southwest Research Institute) presented on February 22 at the Planetary Defense conference of the AIAA (American Institute of Aeronautics and Astronautics). Several paragraphs taken from this paper are reproduced below. Following these quotes from Chapman's paper are additional quotes from a letter Brian Marsden (Minor Planet Center) wrote to CCNet on 14 January on the same subject. Finally, there is a statement posted on the website of the IAU (International Astronomical Union) discussing what lessons we should draw from the story of AL00667, and how such a situation might be better handled in the future.
Asteroids never cease to surprise us. We may never encounter a situation just like this again, but we are fairly sure to have other crises as the rate of discovery of NEAs continues to increase.
David Morrison
FROM CLARK CHAPMAN'S AIAA PAPER "NEO IMPACT SCENARIOS"
presented February 22, 2004
"Just last month (January 2004) perhaps the most surprising impact prediction ever came and went, this time out of the view of the round-the-clock news media. It illustrates how an impact prediction came very close to having major repercussions, even though -- with hindsight -- nothing was ever, in reality, threatening to impact. It is a story of success in that the impact prediction was nullified in record time, less than half-a-day, but the success was accomplished through a set of ad hoc, unofficial, and often unfunded activities and relationships, although assisted in major ways by the official infrastructure, such as it exists (the LINEAR Project, the IAU Minor Planet Center, and the NASA NEO Program Office).
"About 36 hours before President Bush's planned speech at NASA Headquarters on future American space policy, the Lincoln Near Earth Asteroid Research (LINEAR) observatories in New Mexico routinely recorded four images of a moving object. Half a day later, on Tuesday, January 13th, these data were sent (as part of the daily submission of data) to the Minor Planet Center in Cambridge, Massachusetts. Just before going to dinner, MPC research Tim Spahr ran the data through standard software to generate a nominal ephemeris for the new object. These are posted on the publicly accessible NEO Confirmation Page (NEOCP) so that amateur and professional asteroid astronomers around the world might be able to follow up on the LINEAR observations that night. It is through such follow-up astrometry that NEO orbits can be refined so that the object is not permanently lost. Spahr posted the ephemeris, based on LINEAR's four detections, on the NEOCP under the designation AL00667, along with ephemerides for several other recommended targets. Less than an hour later, a European amateur astronomer, Reiner Stoss, went to the NEOCP and noticed a curiosity: AL00667 was predicted to get 40 times brighter during just the next day, meaning that it was going to be six times closer to the Earth! He expressed his amazement on Yahoo's MPML (Minor Planet Mailing List) chatroom on the internet.
"Professional asteroid researcher Alan Harris happened to be monitoring the chatroom and noticed the strange