[meteorite-list] It came from outer space

From: Mike Groetz <mpg444_at_meteoritecentral.com>
Date: Tue, 21 Aug 2007 15:52:30 -0700 (PDT)
Message-ID: <29030.11492.qm_at_web32913.mail.mud.yahoo.com>

It came from outer space

http://www.fresnobee.com/263/story/116802.html

Meteorites provide a spectacular light show for those
watching from Earth. For others, the ancient space
rocks touch off a feverish treasure hunt for fragments
that could be as big as basketballs.

By Carrie Peyton Dahlberg / The Sacramento Bee08/20/07
04:18:05

Robert Ward climbed out of his pickup and ambled
toward four guys gathered around the front porch of a
Tuolumne City house.
"I'm researching a big meteor that blew up near here,"
he began.

Before he left a few minutes later, the guys knew how
to contact him, that he'd pay for meteorites, and that
he wanted to meet with anyone who'd seen the dazzling
flare above Tuolumne County last weekend.

Ward had driven hard from Arizona, lured by that
fireball -- a brilliant, booming event that shook
houses, awakened families and jangled telephones for
sheriff's dispatchers.

He was hunting treasure: ancient space rocks, newly
fallen to earth.

To call Ward's quest a long shot understates it.

Of the hundreds of meteors each year that flare
brightly enough and break apart loudly enough to
prompt multiple calls to authorities, only a few
worldwide lead to meteorite finds, said University of
Arkansas meteor expert Derek Sears.

On top of that, Ward's search had led him to country
ranging from rolling, oak-studded foothills to heavily
forested Sierra peaks. A missing person's car can
languish undiscovered for months there, said Tuolumne
County sheriff's Lt. Dan Bressler.

Ward hoped to narrow his search by persuading
witnesses to stand with him, exactly where they saw
the fireball, and show him its arc through the sky. He
took measurements with an azimuth compass and noted
his position with a GPS, gathering data to pump into
mapping software.

"I've talked with witnesses on three sides now, north
of it, south of it and east of it," he said late
Thursday afternoon, on his first full day in
California.

He was wearing a black baseball cap, decorated with a
redhead sitting astride a blazing meteor. Ward's black
T-shirt bore a sketched meteorite and Norwegian
lettering, the souvenir of a previous expedition.

Ward is among a growing cadre of meteorite collectors,
a field that has boomed with the Internet and improved
hunting technologies.

"I've never been involved in a group that was so
passionate and obsessive about their hobby," said
Geoffrey Notkin, an Arizonan who has bought, sold and
searched for meteorites for 15 years.

While many people devote occasional weekends to the
hobby, a few make a living, mostly traveling to known
sites in deserts or ice fields strewn with meteorites
that fell long ago. They search there, using
sophisticated metal detectors.

"The most successful hunters are bold and determined
and willing to spend a lot of time," Notkin said.

Ward, at 30, qualifies for at least two out of three.
He describes himself as an investor, who has
meteorites on display in every room of his house in
Prescott, Ariz., and who rarely sells his finds.

The burst of light that drew Ward to Sonora was not
the streak of a typical falling star, but its much
brighter cousin, called a fireball.

While not rare, a fireball "is so spectacular we are
poorly calibrated to handle it," said Sears, director
of the Arkansas Center for Space and Planetary
Sciences. People often remember the objects as closer,
brighter and slower than they really were.

Even among fireballs, this one stood out, said Robert
Lunsford, operations manager of the American Meteor
Society, who keeps the society's fireball log.

"This is one of the top 10 events I've had since I
began recording back in 2005," he said, because so
many observers mentioned a delayed sonic boom.

At just after midnight on Aug. 11, it was seen from
Fair Oaks to San Francisco to Gilroy, and filmed by a
Yuba City sky watcher, but the fireball made its most
dramatic appearance above Tuolumne County.

"We got reports from all ends of the county. It was
either bright blue or bright green. It lit up the
entire sky. It lit up Lake Melones so somebody could
see every boat on the lake. The houses shook,"
Bressler said.

Every deputy on patrol called in, 911 lines were
briefly flooded, and throughout the 24 hours,
dispatchers handled 200 more calls than usual.

"It was pretty wild," said sheriff's Corporal Kelly
Dickson, who was driving home when the sky above his
truck lit up twice. "I saw the object explode up in
the sky ... a couple of fragments that were still
glowing split off. .... One was headed east and the
other was headed in a northerly direction."

>From Dickson's description, Sears concluded the
sheriff's officer was probably close to the
retardation point, where a speeding meteor hits denser
atmosphere like a rock slamming into a wall. The force
shatters the rock along its cracks, and whatever
reaches Earth's surface is called a meteorite. Often,
the entire rock is consumed by heat, and nothing is
left to fall.

Based on what the officer saw, Sears said, "There is a
very good chance that there are rocks around the
ground somewhere," probably no closer than 10 miles to
Dickson's location and up to roughly 60 miles north
and east.

Science still has "tons and tons" to learn from
meteorites, the professor said. Although they've been
probed extensively in labs, "almost yearly something
new turns up."

Some of the rarest meteorites come from the moon or
Mars, and others from comets, but most are believed to
speed earthward from the asteroid belt, where rocks
owe their origin to the beginning of the solar system.


"You're holding a rock in your hand that's 4 billion
years old, that formed when we barely had an Earth,"
Sears said, adding that meteorites still give him
goose bumps. "There are sprinklings in there of dust
from other star systems."

Meteorite hunters are as captivated as researchers,
but there's a tension there, too.

"We wouldn't have some fraction of the meteorites we
have if it weren't for those guys. On the other hand,
they prostitute our science because they buy and sell
these precious scientific objects. They make jewelry
out of them. We do wish they weren't so cavalier,"
Sears said.

Like most of those who want to authenticate a find,
Ward said he sends samples to a university, which
keeps a portion in exchange for the analysis.

Meteorites can sell for as little as a dollar or so to
well into the tens of thousands, with some spectacular
finds topping $1 million. A link to a specific
fireball, like the one over Tuolumne County, boosts
value.

Ward said he's willing to spend what's needed to find
these meteorites, if any can be found. He has already
lined up people to help him walk a search area, once
he zeros in on a potential location.

He has metal detectors at ready, to pick up the iron
found in the vast majority of meteorites. He's
prepared, he said, to compensate landowners, who own
any meteorites that fall on their property unless
they've sold mineral rights to someone else.

On Friday, after heading higher and higher into the
Sierra, Ward predicted he's still at least a few days
away from a foot search.

He'll be looking for black rocks the size of pebbles,
or maybe if he's lucky, basketballs.



       
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Received on Tue 21 Aug 2007 06:52:30 PM PDT