[meteorite-list] Eight Billion 'Dark Asteroids' May Lurk in OortCloud

From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Sat, 6 Dec 2014 23:25:06 -0600
Message-ID: <96174.98571.bm_at_smtp117.sbc.mail.gq1.yahoo.com>

Ron, List,

> Don't fear, though: The team estimates
> that a planet-killing collision with
> such an object might happen only once
> every billion years or so.

I've got a well-known quote for you...

> "You've gotta ask yourself one question:
> 'Do I feel lucky?' Well, do ya, punk?"

Sterling Webb
------------------------------------------
-----Original Message-----
From: Meteorite-list [mailto:meteorite-list-bounces at meteoritecentral.com] On
Behalf Of Ron Baalke via Meteorite-list
Sent: Saturday, December 06, 2014 6:35 PM
To: Meteorite Mailing List
Subject: [meteorite-list] Eight Billion 'Dark Asteroids' May Lurk in
OortCloud

http://news.sciencemag.org/space/2014/12/eight-billion-dark-asteroids-may-lu
rk-oort-cloud

Eight billion 'dark asteroids' may lurk in Oort cloud By Sid Perkins Science
Magazine
4 December 2014

Our solar system's asteroid belt, which lies between Mars and Jupiter, may
contain a few hundred thousand objects. But much farther away, in regions
long presumed to be the realm of comets and other icy bodies, there could be
billions of rocky orbs circling the sun, a new study suggests.
 
Researchers used computer programs to simulate the fate of objects circling
our young sun once its planetary disk was largely cleared of gas and dust.
Gravitational interactions with planets over the subsequent 4.5 billion
years caused some objects to crash into the sun and others to be flung out
of the solar system altogether. But many of the objects were cast into exile
in the Oort cloud, a spherical haze of objects that stretches far beyond
Neptune and a good fraction of the way toward our nearest stellar neighbors.
(The image above depicts the Oort cloud as compared with the solar system
and the much nearer Kuiper belt of objects.) Of those deportees, about 4%
came from within about 375 million kilometers of the sun, rendering them
rock- or metal-rich bodies like asteroids rather than icy orbs like comets,
the researchers report online ahead of print in the Monthly Notices of the
Royal Astronomical Society. Previous observations suggest that the Oort
cloud contains about 200 billion comets, the researchers note.

If that's correct, the new results suggest that those comets are accompanied
by about 8 billion asteroids. If one of those objects ever fell toward
Earth, it would be tougher to spot than a comet (being much darker) and more
difficult to divert than the typical near-Earth asteroid (as it would be
traveling much faster). Don't fear, though: The team estimates that a
planet-killing collision with such an object might happen only once every
billion years or so.
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Received on Sun 07 Dec 2014 12:25:06 AM PST