[meteorite-list] Odd rock may have spawned asteroid family

From: Mike Groetz <mpg444_at_meteoritecentral.com>
Date: Wed, 14 Mar 2007 14:35:37 -0700 (PDT)
Message-ID: <991760.13782.qm_at_web32909.mail.mud.yahoo.com>

http://www.cnn.com/2007/TECH/space/03/14/odd.space.rock/index.html

Odd rock may have spawned asteroid family

Story Highlights? Scientists link five asteroids to an
oblong-shaped rock out near Pluto
? The rock, known as 2003 EL61, is shaped like an
American football
? 2003 EL61 might eventually become a comet

CHICAGO, Illinois (Reuters) -- In a solar system of
heavenly bodies, scientists have discovered an ugly
duckling -- an oblong-shaped rock in the vicinity of
Pluto that may one day light up Earth's sky as a giant
comet.

The rock, known as 2003 EL61, is one of the strangest
objects in the solar system. It is shaped like an
American football and completely rotates every four
hours.

"Out in space there is this crazy thing spinning end
to end that is as big as Pluto," said Mike Brown, a
professor of planetary astronomy at the California
Institute of Technology who discovered the object two
years ago.

Brown and colleagues at Caltech believe it got its odd
shape after a collision with another object about 4.5
billion years ago that sent chunks of the rock
scattering, creating two moons and a lot of space
debris.

"When we tried to find out what it was made of we
found that it was mostly rock. Nothing else out there
is made out of rock. Everything else out there is made
out of ice," Brown said in a telephone interview.

"We thought maybe a long time ago something ran into
it and knocked off all of the ice, and hit it so hard
it got it spinning -- and the spinning is what made it
shaped like a football," Brown said.

Now, the Caltech team has found some proof.

They found a family of five objects that likely are
the offspring of this giant spinning rock. The objects
were found in an area of the solar system beyond
Neptune where no other asteroid families have been
found.

"They got blasted off in this big impact," Brown said.
"The chunks left the main body but they are still
close by in orbit around the sun."

The new findings, reported in the journal Nature,
might make 2003 EL61 one of the most important objects
in the neighborhood, a region on the outer edge of the
solar system known as the Kuiper belt that contains
the dwarf planets Eris and Pluto.

The disk-shaped region is about 2.8 billion to 4.6
billion miles from the sun, according to the National
Aeronautics and Space Administration. "It's on the
ragged edge of the solar system," Brown said.

While space collisions are fairly common within the
asteroid belt in the inner solar system, they have
never been spotted in the region of the solar system
beyond Neptune.

Because orbits in that region are not stable, the
scientists at Caltech believe some of the fragments
from the giant rock may have already made their way to
the inner solar system as comets, and some may have
even hit Earth.

Brown believes 2003 EL61 might eventually become a
comet. If it does, it would be as bright as the full
moon and easily visible in the daytime sky.

"It will be something like 6,000 times brighter than
Hale-Bopp," he said.

But people shouldn't get out their telescopes just
yet. If the giant football rock becomes a comet, it
would not be visible from Earth for a billion years.

"It will be the biggest comet anyone has every
seen--if there's anyone around to see it," he said.



 
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Received on Wed 14 Mar 2007 05:35:37 PM PDT