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

[Jerry A. Wallace]

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.