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Jet Propulsion Laboratory, Pasadena, Calif.
agle@jpl.nasa.gov
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NASA Headquarters, Washington
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NEWS RELEASE: 2007-152 Dec. 21, 2007
Astronomers Monitor Asteroid to Pass Near Mars
WASHINGTON - Astronomers funded by NASA are monitoring the trajectory of an
asteroid estimated to be 50 meters (164 feet) wide that is expected to cross Mars' orbital
path early next year. Observations provided by the astronomers and analyzed by NASA's
Near-Earth Object Office at the Jet Propulsion Laboratory in Pasadena, Calif., indicate the
object may pass within 30,000 miles of Mars at about 6 a.m. EST (3 a.m. PST) on Jan. 30,
2008.
"Right now asteroid 2007 WD5 is about half-way between Earth and Mars and closing the
distance at a speed of about 27,900 miles per hour," said Don Yeomans, manager of the
Near Earth Object Office at JPL. "Over the next five weeks, we hope to gather more
information from observatories so we can further refine the asteroid's trajectory."
NASA detects and tracks asteroids and comets passing close to Earth. The Near Earth
Object Observation Program, commonly called "Spaceguard," plots the orbits of these
objects to determine if any could be potentially hazardous to our planet.
Asteroid 2007 WD5 was first discovered on Nov. 20, 2007, by the NASA-funded Catalina
Sky Survey and put on a "watch list" because its orbit passes near Earth. Further
observations from both the NASA-funded Spacewatch at Kitt Peak, Ariz., and the
Magdalena Ridge Observatory in New Mexico gave scientists enough data to determine
that the asteroid was not a danger to Earth, but could potentially impact Mars. This makes
it a member of an interesting class of small objects that are both near Earth objects and
"Mars crossers."
Because of current uncertainties about the asteroid's exact orbit, there is a 1-in-75 chance
of 2007 WD5 impacting Mars. If this unlikely event were to occur, it would be somewhere
within a broad swath across the planet north of where the Opportunity rover is located.
"We estimate such impacts occur on Mars every thousand years or so," said Steve Chesley,
a scientist at JPL. "If 2007 WD5 were to thump Mars on Jan. 30, we calculate it would hit
at about 30,000 miles per hour and might create a crater more than half-a-mile wide." The
Mars Rover Opportunity is exploring a crater approximately this size right now.
Such a collision could release about three megatons of energy. Scientists believe an event
of comparable magnitude occurred here on Earth in 1908 in Tunguska, Siberia, but no
crater was created. The object was disintegrated by Earth's thicker atmosphere before it hit
the ground, although the air blast devastated a large area of unpopulated forest.
NASA and its partners will continue to track asteroid 2007 WD5 and will provide an
update in January when further information is available. For more information on the Near
Earth Object program, visit:
http://neo.jpl.nasa.gov/ .
An audio interview/podcast regarding 2007 WD5 is available at:
http://www.jpl.nasa.gov/multimedia/podcast/mars-asteroid-20071221/
A videofile related to this story is available on NASA TV and the Web. For information
and schedules, visit:
http://www.nasa.gov/ntv.
-end-
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