Subject: Correction to LSST SWG minutes

From: David Morrison

Submitted: Tue, 25 Feb 2003 12:01:49 -0800

Message number: 78 (previous: 77, next: 79 up: Index)

Please allow me to provide a different perspective on the nature of 
the NEO impact hazard problem that the LSST is addressing.

In the minutes that Mike Strauss just circulated, he wrote that "most 
of what LSST does in terms of improving our understanding of the risk 
is finishing up the last 10%, rather than improving statistics of 
200-300 meter objects." This is not a good way to look at the impact 
hazard or the role of the LSST. From the perspective of planetary 
protection (impact mitigation), there is NO ROLE in  either 
"improving our understanding of the risk" or "improving statistics". 
These are not the issues.

We know the statistics and the risks just fine -- what we need is to 
find the individual objects, one at a time. There either is or is not 
an asteroid that will hit the Earth in the next century (not likely 
to be more than one). If it exists, it is a real solid object that 
can be located and perhaps deflected. The public requirement is to 
find such objects before they hit. Improving statistics has nothing 
to do with it. Many science problems can be solved by sampling and 
statistics, but answering the question of whether there is an 
asteroid out there with our name on it is not such a problem.

This is not a statistical problem. We have got to keep this 
distinction straight!

David Morrison
-- 
+++++++++++++++++++++++++++++++++++++++++++

David Morrison, NASA Ames Research Center 240-1
Tel 650 604 5094; Fax 650 604 4251
david.morrison@arc.nasa.gov or dmorrison@arc.nasa.gov
website: http://astrobiology.arc.nasa.gov
website: http://nai.arc.nasa.gov
website: http://impact.arc.nasa.gov

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