[BR-Crater] asteroid now 1-in-25 chance to impact Mars

[Ian Kluft]

JPL has updated the chance for asteroid 2007 WD5 to impact Mars from
1-in-75 to 1-in-25 based on a PhD student's search of archives of
past observations which refined the estimate of the asteroid's orbit.
So in other words, it's now *up* to a 4% chance of an impact. It's
still a long shot, but higher chance than before.

   "Mars Impact Probability Increases to 4 Percent" (JPL)
   http://neo.jpl.nasa.gov/news/news153.html

   "Chance of asteroid hit on Mars increases" (AP via San Jose Mercury News)
   http://www.mercurynews.com//ci_7831131

I expect updates as they make more observations.  According to the news,
JPL scientist Don Yeomans said it's common for the probablility to increase
briefly before a new observation mathematically eliminates the chance of
an impact entirely.  We'll keep watching...

The JPL release says, "In the unlikely event of an impact, the time would
be 2008 January 30 at 10:56 UT (2:56 a.m. PST) with an uncertainty of a
few minutes."

I ran a sky chart on heavens-above.com for the time.  From around here,
Mars will be low to the WNW and the last-quarter moon will be low in the
SE.  I agree with Randall Clague's impression (which he posted on the
Stratofox Talk list) that an impact may have a chance to be observable.
   http://www.heavens-above.com/skychart.asp?Y=2008&M=1&D=31&H=2&N=56&Lat=37.4&Lng=-121.8&Loc=SJ&TZ=PST&SL=on&SN=on&BW=0&SZ=500