Alaska astrophysicist raises odds of Mars asteroid strike

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ANCHORAGE, Alaska -- The odds are it will miss. Still, there's a huge asteroid -- a massive rock about 160 feet long -- hurtling toward Mars.Two weeks ago, NASA scientists said the chances it would collide with the Red Planet were 1 in 75. Now they say it's 1 in 28, and astronomers and physicists are beginning to take notice. As they do, the scientists can credit Andrew Puckett, a 30-year-old astrophysicist conducting post-doctoral research at the University of Alaska Anchorage.Working on his own during Christmas break, Puckett discovered archival data that allowed NASA to refine its forecast on what's now being called "Asteroid 2007 WD5.""When I submitted the information, all I knew was that I was changing the (projected) orbit," Puckett said in a telephone interview ."I was sure I would also change the impact odds, but I had no idea whether it would go up or down. So the fact that it went up -- and became a big story -- is just really exciting for me."It might become exciting for a lot of other people as well, says UAA physics and astronomy professor Travis Rector, who supervises Puckett's research -- if the asteroid actually hits Mars. Such an explosion -- a force equivalent to a 3-megaton nuclear bomb -- would leave a crater on Mars about a half mile wide. Exploring it with satellites and terrestrial rovers could allow scientists to answer questions about whether life forms have ever existed on other planets."If you consider the importance of that -- it would be an amazing event if it occurs," Rector said.Typically the odds that any of the asteroids that NASA regularly tracks through its Near Earth Object Program will ever strike home -- or even a neighboring planet -- are tiny, Rector said."They're like 'one in 10,000' and that sort of thing. So it's a very big deal, and it's getting a lot of attention."Scientists began to perk up in November, after 2007 WD5 whizzed past Earth at about 30,000 miles an hour -- then resumed its orbit toward the outer solar system on a trajectory that would take it even closer to Mars.On Dec. 21, the NASA Near Earth Object Program reported the chances that the flying rock might actually hit Mars were about 1.3 percent. But the space agency's revised forecast on Dec. 28 -- using data provided by Puckett -- increased that likelihood to 3.9 percent.How'd he come by such information himself?Last year, after earning a Ph.D. in astronomy and astrophysics while studying comets and asteroids at the University of Chicago, Puckett was hired by UAA to help develop a new physics and astronomy curriculum -- an initiative supported by a $500,000 grant from the National Science Foundation.Separate from that mission, however, he'd continued to pay attention to obscure objects in our solar system -- and on Dec. 21 was startled to hear news of the proximity to Earth of 2007 WD5. (Though it missed us by 5 million miles, Puckett says, that counts as close, in asteroid distance.)Because of his familiarity with tracking asteroids through images available online in the Sloan Digital Sky Survey -- a database principally used to monitor distant galaxies -- Puckett was able to provide earlier plot points for 2007 WD5.After working out some calculations on Christmas Day, he sent his findings to the Minor Planet Center at Harvard. The university, in turn, provided the information to NASA's Jet Propulsion Laboratory in California. Then just before New Year's Day, NASA readjusted the chances the asteroid will strike Mars.Now Puckett is rooting for a direct hit ."I hope it happens," he told a UAA publicist last week, noting that such a cataclysm would also draw attention to the general threat asteroids pose toward Earth.On the Net Read the Discovery Channel's report on the asteroid atdsc.discovery.com/news/2008/01/02/mars-asteroid-strike.htmlFind Andrew Puckett's recalculation atneo.jpl.nasa.gov/news/news153.html(Distributed by Scripps Howard News Service, www.scrippsnews.com.)