near-earth asteroid  Survey finds fewer near-Earth asteroids
than once thought  Analysis of data collected by a NASA infrared
space telescope shows there are fewer near-Earth asteroids than
previously believed, scientists said today.  But the majority of
the nearly 20,000 bodies between 330 and 3,300 feet wide have
not yet been detected and it's not yet clear whether a reduced
population also means a reduced number of midsize asteroids in
orbits that could pose a threat to Earth.  "We find that there
are fewer near-Earth asteroids out there," said Amy Mainzer,
principal investigator with NASA's NEOWISE program. "However,
it's very important to note that fewer does not mean none. And
there are still tens of thousands that are out there that we
need to find."  Using NASA's Wide-Field Infrared Survey Explorer
--WISE--space telescope, researchers conducted a census of near-
Earth objects, or NEOs, orbiting within 120 million miles of the
sun. Scanning the entire sky twice between January 2010 and
February 2011, the