[ExI] Asteroid on track for possible (probability of 1:25) Mars hit

Amara Graps amara at amara.com
Mon Dec 31 20:34:23 UTC 2007

a caveat :

>Note from David Morrison: "In case of a close pass (but a miss), it 
>is normal for the impact odds to increase before they drop to zero. 
>This is because there is a time, as knowledge of the orbit improves, 
>when the error ellipse (the uncertainty in the miss distance) 
>shrinks while the target (in this case Mars) remains within the 
>ellipse. Thus the change in odds of a hit from 1 in 75 to 1 in 25 
>does not mean it will hit -- it still has a 96% chance of missing -- 
>but it sure is interesting! It would be even more "interesting" if 
>the target were Earth not Mars. Think about it."


Amara Graps, PhD      www.amara.com
Research Scientist, Southwest Research Institute (SwRI), Boulder, Colorado

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