[meteorite-list] Ten Thousandth Near-Earth Object Unearthed in Space (Asteroid 2013 MZ5)

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon, 24 Jun 2013 15:01:40 -0700 (PDT)
Message-ID: <201306242201.r5OM1eZs026790_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.php?release=2013-207

Ten Thousandth Near-Earth Object Unearthed in Space
Jet Propulsion Laboratory
June 24, 2013

More than 10,000 asteroids and comets that can pass near Earth have now
been discovered. The 10,000th near-Earth object, asteroid 2013 MZ5, was
first detected on the night of June 18, 2013, by the Pan-STARRS-1
telescope, located on the 10,000-foot (convert) summit of the Haleakala
crater on Maui. Managed by the University of Hawaii, the PanSTARRS
survey receives NASA funding.

Ninety-eight percent of all near-Earth objects discovered were first
detected by NASA-supported surveys.

"Finding 10,000 near-Earth objects is a significant milestone," said
Lindley Johnson, program executive for NASA's Near-Earth Object
Observations Program at NASA Headquarters, Washington. "But there are at
least 10 times that many more to be found before we can be assured we
will have found any and all that could impact and do significant harm to
the citizens of Earth." During Johnson's decade-long tenure, 76 percent
of the NEO discoveries have been made.

Near-Earth objects (NEOs) are asteroids and comets that can approach the
Earth's orbital distance to within about 28 million miles (45 million
kilometers). They range in size from as small as a few feet to as large
as 25 miles (41 kilometers) for the largest near-Earth asteroid, 1036
Ganymed.

Asteroid 2013 MZ5 is approximately 1,000 feet (300 meters) across. Its
orbit is well understood and will not approach close enough to Earth to
be considered potentially hazardous.

"The first near-Earth object was discovered in 1898," said Don Yeomans,
long-time manager of NASA's Near-Earth Object Program Office at the Jet
Propulsion Laboratory in Pasadena, Calif. "Over the next hundred years,
only about 500 had been found. But then, with the advent of NASA's NEO
Observations program in 1998, we've been racking them up ever since. And
with new, more capable systems coming on line, we are learning even more
about where the NEOs are currently in our solar system, and where they
will be in the future."

Of the 10,000 discoveries, roughly 10 percent are larger than a sixth of
a mile (one kilometer) in size - roughly the size that could produce
global consequences should one impact the Earth. However, the NASA NEOO
program has found that none of these larger NEOs currently pose an
impact threat and probably only a few dozen more of these large NEOs
remain undiscovered.

The vast majority of NEOs are smaller than one kilometer, with the
number of objects of a particular size increasing as their sizes
decrease. For example, there are expected to be about 15,000 NEOs that
are about one-and-half football fields in size (460 feet, or 140
meters), and more than a million that are about one-third a football
field in size (100 feet, or 30 meters). A NEO hitting Earth would need
to be about 100 feet (30 meters) or larger to cause significant
devastation in populated areas. Almost 30 percent of the 460-foot-sized
(40-meter-sized) NEOs have been found, but less than 1 percent of the
100-foot-sized NEOs have been detected.

When it originated, the NASA-instituted Near-Earth Object Observations
Program provided support to search programs run by the Massachusetts
Institute of Technology's Lincoln Laboratory (LINEAR); the Jet
Propulsion Laboratory (NEAT); the University of Arizona (Spacewatch, and
later Catalina Sky Survey) and the Lowell Observatory (LONEOS). All
these search teams report their observations to the Minor Planet Center,
the central node where all observations from observatories worldwide are
correlated with objects, and they are given unique designations and
their orbits are calculated.

"When I began surveying for asteroids and comets in 1992, a near-Earth
object discovery was a rare event," said Tim Spahr, director of the
Minor Planet Center. "These days we average three NEO discoveries a day,
and each month the Minor Planet Center receives hundreds of thousands of
observations on asteroids, including those in the main-belt. The work
done by the NASA surveys, and the other international professional and
amateur astronomers, to discover and track NEOs is really remarkable."

Within a dozen years, the program achieved its goal of discovering 90
percent of near-Earth objects larger than 3,300 feet (1 kilometer) in
size. In December 2005, NASA was directed by Congress to extend the
search to find and catalog 90 percent of the NEOs larger than 500 feet
(140 meters) in size. When this goal is achieved, the risk of an
unwarned future Earth impact will be reduced to a level of only one
percent when compared to pre-survey risk levels. This reduces the risk
to human populations, because once an NEO threat is known well in
advance, the object could be deflected with current space technologies.

Currently, the major NEO discovery teams are the Catalina Sky Survey,
the University of Hawaii's Pan-STARRS survey and the LINEAR survey. The
current discovery rate of NEOs is about 1,000 per year.

NASA's Near-Earth Object Observations Program manages and funds the
search for, study of and monitoring of asteroids and comets whose orbits
periodically bring them close to Earth. The Minor Planet Center is
funded by NASA and hosted by the Smithsonian Astrophysical Observatory
in Cambridge, MA. JPL manages the Near-Earth Object Program Office for
NASA's Science Mission Directorate in Washington. JPL is a division of
the California Institute of Technology in Pasadena. More information
about asteroids and near-Earth objects is available at:
http://neo.jpl.nasa.gov/, http://www.jpl.nasa.gov/asteroidwatch and via
Twitter at http://www.twitter.com/asteroidwatch .

DC Agle
Jet Propulsion Lab., Pasadena, Calif.
818-393-9011
agle at jpl.nasa.gov

2013-207
Received on Mon 24 Jun 2013 06:01:40 PM PDT