January 8, 2008
"Ladies and gentlemen, we will blow up the moon."
Posted by pete at January 8, 2008 1:44 PMOr Mars, whatever.
A small asteroid discovered November 20 may strike Mars next month.
Astronomers with NASA's Near Earth Object (NEO) Program at the Jet Propulsion Laboratory in Pasadena, California, calculate the odds of a January 30 collision at 1 in 75. While this is remote, it's less so than last week's estimated 1-in-350 chance.
NEO astronomer Steve Chesley, who's used to dealing with million-to-one odds, calls the event "extremely unusual," and, in something of a twist, NEO astronomers are rooting for an impact.
An armada of spacecraft orbiting the Red Planet - the European Space Agency's Mars Express and NASA's Mars Reconnaissance Orbiter and Mars Odyssey - would have ringside seats to view the strike and its after-effects. Even Earth-based telescopes could potentially observe the impact because Mars is near opposition and, therefore, unusually close.
I still love the name "Near Earth Object Program." And they have all these sweet graphics, even:
Astronomers say asteroid 2007 WD5 is about 160 feet (50 meters) across. If it struck Mars, the energy would be similar to the 1908 Tunguska blast in Siberia, where a stony asteroid exploded above the taiga. The blast felled and scarred trees over 810 square miles (2,100 square km).
One difference: Tunguska was an air burst and left no crater, whereas 2007 WD5 likely would reach Mars' surface intact.
Or it would, if not for the latest update:
Additional position observations for asteroid 2007 WD5 taken on December 29 through January 2 have been used to improve the accuracy of the asteroid's orbit. As a result, the range of possible paths past Mars has narrowed by a factor of 3 and the most likely path has moved a little farther away from the planet, causing the Mars impact probability to decrease slightly to 3.6% (about one chance in 28). The new positional observations were made using the 2.4 meter telescope at New Mexico Tech's Magdalena Ridge Observatory and reported by astronomer Bill Ryan. It seems likely that as additional observations further shrink the uncertainty region of this asteroid, the region will no longer intersect Mars and the impact probability will quickly drop to zero.
This is a serious blow: not just to the cause of wicked cool astronomical photography, but also to our ongoing war against the Martians, whose offensive tripod production will now continue dangerously unabated.