[meteorite-list] NASA Says Comet Elenin Gone and Should Be Forgotten

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue, 25 Oct 2011 16:54:42 -0700 (PDT)
Message-ID: <201110252354.p9PNsgh0017101_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.cfm?release=2011-331

NASA Says Comet Elenin Gone and Should Be Forgotten
Jet Propulsion Laboratory
October 25, 2011

Comet Elenin is no more.

Latest indications are this relatively small comet has broken into even
smaller, even less significant, chunks of dust and ice. This trail of
piffling particles will remain on the same path as the original comet,
completing its unexceptional swing through the inner solar system this fall.

"Elenin did as new comets passing close by the sun do about two percent
of the time: It broke apart," said Don Yeomans of NASA's Near-Earth
Object Program Office in Pasadena, Calif. "Elenin's remnants will also
act as other broken-up comets act. They will trail along in a debris
cloud that will follow a well-understood path out of the inner solar
system. After that, we won't see the scraps of comet Elenin around these
parts for almost 12 millennia."

Twelve millennia may be a long time to Earthlings, but for those frozen
inhabitants of the outer solar system who make this commute, a dozen
millennia give or take is a walk in the celestial park. Comet Elenin
came as close as 45 million miles (72 million kilometers) to the sun,
but it arrived from the outer solar system's Oort Cloud, which is so far
away its outer edge is about a third of the way to the nearest star
other than our sun.

For those broken up over the breakup of what was formerly about 1.2
miles (two kilometers) of uninspiring dust and ice, remember what
Yeomans said about comets coming close to the sun - they fall apart
about two percent of the time.

"Comets are made up of ice, rock, dust and organic compounds and can be
several miles in diameter, but they are fragile and loosely held
together like dust balls," said Yeomans. "So it doesn't take much to get
a comet to disintegrate, and with comets, once they break up, there is
no hope of reconciliation."

Comet Elenin first came to light last December, when sunlight reflecting
off the small comet was detected by Russian astronomer Leonid Elenin of
Lyubertsy, Russia. Also known by its astronomical name, C/2010 X1,
Elenin somehow quickly became something of a "cause c??l??bre" for a few
Internet bloggers, who proclaimed this minor comet could/would/should be
responsible for causing any number of disasters to befall our planet.

Internet posts began appearing, many with nebulous, hearsay observations
and speculations about earthquakes and other disasters being due to
Elenin's gravitational effects upon Earth. NASA's response
<http://www.jpl.nasa.gov/news/news.cfm?release=2011-255> to such wild
speculations was then in turn speculated to be an attempt to hide the truth.

"I cannot begin to guess why this little comet became such a big
Internet sensation," said Yeomans. "The scientific reality is this
modest-sized icy dirtball's influence upon our planet is so incredibly
miniscule that my subcompact automobile exerts a greater gravitational
influence on Earth than the comet ever would. That includes the date it
came closest to Earth (Oct. 16), when the comet's remnants got no closer
than about 22 million miles (35.4 million kilometers)."

Yeomans knows that while Elenin may be gone, there will always be
Internet rumors that will attempt to conjure up some form of
interplanetary bogeyman out of Elenin, or some equally obscure and
scientifically uninteresting near-Earth object. Thinking of ways to
make himself any more clear about the insignificance of this matter is
somewhat challenging for a scientist who has dedicated his life to
observing asteroids and comets and discovering their true nature and
effects on our solar system.

"Perhaps a little homage to a classic Monty Python dead parrot sketch is
in order," said Yeomans. "Comet Elenin has rung down the curtain and
joined the choir invisible. This is an ex-comet."

NASA detects, tracks and characterizes asteroids and comets passing
relatively close to Earth using both ground- and space-based telescopes.
The Near-Earth Object Observations Program, commonly called
"Spaceguard," discovers these objects, characterizes the physical nature
of a subset of them, and predicts their paths to determine if any could
be potentially hazardous to our planet. There are no known credible
threats to date.

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 at:
http://www.jpl.nasa.gov/asteroidwatch , and on Twitter: _at_asteroidwatch .

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

2011-331
Received on Tue 25 Oct 2011 07:54:42 PM PDT