Date: Thu, 17 May 2012 19:21:11 -0400
From: mark <whitroth at 5-cent.us>
To: "gt-pfrc at ml.gt.org" <gt-pfrc at ml.gt.org>,
 WSFA members <WSFAlist at KeithLynch.net>,
 WSFA Official List <wsfa-forum at yahoogroups.com>, bsfsgeneral at bsfs.org
Subject: [WSFA] NASA counts 4,700 potentially hazardous near-Earth asteroids
Reply-To: WSFA members <WSFAlist at KeithLynch.net>

Excerpt:
The new numbers come from asteroid observations made by NASA's
Wide-field Infrared Survey Explorer, (WISE) satellite which looked at
the objects that orbit within 120 million miles of the of the sun into
Earth's orbital vicinity, NASA said. WISE scanned the celestial sky
twice in infrared light between January 2010 and February 2011,
continuously snapping pictures of everything from distant galaxies to
near-Earth asteroids and comets.  It has since entered hibernation mode,
NASA stated.   The asteroid-hunting portion of the WISE mission called
NEOWISE has seem more than 100 thousand asteroids in the main belt
between Mars and Jupiter, in addition to at least 585 near Earth, NASA
noted.

Specifically NASA said NEOWISE sampled 107 PHAs to make predictions
about the entire population as a whole. Findings indicate there are
roughly 4,700 PHAs, plus or minus 1,500, with diameters larger than 330
feet (about 100 meters). So far, an estimated 20 to 30% of these objects
have been found, NASA stated.  Previous estimates of PHAs predicted
similar numbers, they were rough approximations, NASA said.

"The NEOWISE analysis shows us we've made a good start at finding those
objects that truly represent an impact hazard to Earth," said Lindley
Johnson, program executive for the Near-Earth Object Observation Program
at NASA Headquarters in Washington. "But we've many more to find, and it
will take a concerted effort during the next couple of decades to find
all of them that could do serious damage or be a mission destination in
the future."
--- end excerpt ---

<http://www.networkworld.com/community/blog/nasa-counts-4700-potentially-hazardous-near-earth-asteroids>

        mark
--
Today's politicians know what to do when it hits the fan.  They
redesignate it a Rotary Waste Impeller. And blame the R\e\d\s\
\H\i\p\p\i\e\s\ \O\t\h\e\r\ \S\i\d\e\ \o\f\ \t\h\e\ \A\i\s\l\e\
terrorists if there are any complaints. - Stickmaker