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RE: [cdn-nucl-l] " Earth At Risk: New Calls For Planetary Defense "
Jim Dukelow and Andy English wrote:
From: Dukelow, James S Jr
Sent: Saturday, February 28, 2004 2:55 PM
To: Englishes; Jaro; multiple cdn
Subject: RE: [cdn-nucl-l] " Earth At Risk: New Calls For Planetary
Andy English wrote:
From: Englishes [mailto:email@example.com]
Sent: Sat 2/28/2004 10:45 AM
To: Jaro; multiple cdn
Subject: Re: [cdn-nucl-l] " Earth At Risk: New Calls For
Planetary Defense "
Is this the same crowd that are searching for extraterrestrial
intelligence, or just another example of the paranoid security
establishment gone mad? Are these people for real? Cheers, Andy
Jim Dukelow responding:
<snip> ... but it appears that all of the scientists quoted in the
article are [for real].
David Morrison and his colleague Chris [?] Chapman, Southwest Research
Institute, had a paper in Nature about a decade ago that estimated the
risk from strikes of various sizes of near-earth objects. Their
conclusion was that the risks fell well within the range of risks that
we spend lots of money to prevent or mitigate. Their estimated risk was
dominated by ocean strikes of "middle-sized" objects that caused a few
tens or hundreds of millions of deaths around the coastlines of the
impacted ocean basin. Smaller risks were associated with small objects
and end-of-the-world strikes of large objects.
Added on 4 March 2004
Today's issue of our little desert metropolitan newspaper reprints a
Philadelphia Inquirer article bearing on this topic.
The Inquirer reports that on Jan 13 of this year, scientists reported to
the loosely organized Minor Planet Center in Cambridge, Massachusetts,
on the existence of asteroid 2004 AS 1. Initial observations suggested
that it was about 30 meters in diameter and that there was a 1 in 4
chance that it would impact somewhere in the Northern Hemisphere in a
couple of days. This prediction was based on only four observations.
For nine hours, astronomers Clark Chapman and David Morrison, chair of
the International Astronomical Union's Worker Group, considered
informing the President. At that point, a new observation refined the
orbit and increased the size to 500 meters in diameter. Following the
refined orbit 2004 AS1 missed the earth by 7 million miles.
The Inquirer story concludes: "We need a tighter system, probably an
international system, of level-headed astronomers who will place the
call only when they see no other choice. <new paragraph> The story here
was not of an asteroid that almost brought disaster, but of a phone call
that almost did."
My comment is that Chapman and Morrison seem to meet the definition of
"level-headed astronomers" and the Minor Planet Center the definition of
an international system. It is an interesting risk management question
how long Chapman and Morrison SHOULD have waited for better information
before informing the rest of the world. Until there was a day left?
Pacific Northwest National Laboratory
These comments are mine and have not been reviewed and/or approved by my
management or by the U.S. Department of Energy