[meteorite-list] Astronomers catch a shooting star for 1st time - Yahoo! News

From: Jerry A. Wallace <jwal2000_at_meteoritecentral.com>
Date: Wed, 25 Mar 2009 17:07:21 -0500
Message-ID: <49CAAB19.4070109_at_swbell.net>

For what it's worth:

http://news.yahoo.com/s/ap/20090325/ap_on_sc/sci_asteroid_match


<http://news.yahoo.com/nphotos/NASA/photo//090325/481/c461e8c1701c49619796a4a26bea61a0//s:/ap/20090325/ap_on_sc/sci_asteroid_match>AP
? This December 2008 photo, released by NASA, shows a black chunk of
rock found in the Sudan desert, the ?
By SETH BORENSTEIN, AP Science Writer Seth Borenstein, Ap Science Writer
? 1 hr 8 mins ago

WASHINGTON ? For the first time scientists matched a meteorite found on
Earth with a specific asteroid that became a fireball plunging through
the sky. It gives them a glimpse into the past when planets formed and
an idea how to avoid a future asteroid Armageddon.

Last October, astronomers tracked a small non-threatening asteroid
heading toward Earth before it became a "shooting star," something they
had not done before. It blew up in the sky and scientists thought there
would be no space rocks
<http://news.yahoo.com/s/ap/20090325/ap_on_sc/sci_asteroid_match#> left
to examine.

But a painstaking search by dozens of students through the remote Sudan
desert came up with 8.7 pounds of black jagged rocks, leftovers from the
asteroid 2008 TC3. And those dark rocks were full of surprises and
minuscule diamonds, according to a study published Thursday in the
journal Nature.

"This was a meteorite that was not in our collection, a completely new
material," said study lead author Peter Jenniskens of NASA's Ames
Research Center in California. For years, astronomers have been lobbying
to send a robot probe to an asteroid, grab a chunk of it and return it
to Earth for labs to analyze the material. Instead a piece of an
asteroid dropped in their laps and the researchers were able to track
where it came from and where it landed.

The asteroid, which mostly burned in the atmosphere 23 miles above the
ground, is likely a leftover from when chunks of rock tried and failed
to become a planet, about 4.5 billion years ago, scientists said.

"This is a look back in time and it came to us," said University of
Maryland astronomer Lucy McFadden. She wasn't part of the study, but
like four other outside experts praised the findings as important to the
understanding of the solar system.

"It's a beautiful example of looking at an earlier stage of planet
development that was arrested, halted," said NASA cosmic mineralogist
Michael Zolensky, a co-author of the study.

But it also serves as a lesson for the future if this asteroid's big
brother comes hurtling toward Earth.

Blowing it up like in the Bruce Willis movie "Armageddon" wouldn't be
smart because this type of asteroid turns out to be very much like a
"traveling sandpile," Zolensky said. "If you blow it up, all the pieces
are heading toward Earth."

Instead, a spaceship-aided nudge would be more effective, said NASA Ames
Research Center director Simon "Pete" Worden, another study co-author.
He is a longtime advocate of a worldwide program to plan for the threat
of asteroids and comets hitting Earth.

"The real important issue is to understand the physics of these
objects," Worden said.

There are many different types of asteroids, all classified from afar
based on color and light wavelengths. This type is called class F and
turns out to be mostly porous and fragile. University of Maryland's
McFadden said it's unlikely that a class F asteroid could be any danger
to Earth, even if it's bigger, because of its porous makeup which would
cause it to break up before hitting.

It was full of metals, such as iron and nickel, and organics such as
graphites, Zolensky said. And most interesting is that it has
"nanodiamonds." These diamonds are formed by collisions in space and
high pressure and they are all over the rocks, making them glitter like
geodes, he said. But they aren't big.

"If bacteria had engagement rings, these would be the right size for
them," Zolensky said.
Received on Wed 25 Mar 2009 06:07:21 PM PDT