“You don’t often have kiloton rocks flying over your head,” he
said.
The boom, another expert said, was caused by the speed with which the space
rock entered the atmosphere. Meteorites enter Earth’s upper atmosphere at
speeds of up to 44,000mph – faster than the speed of sound, thus creating a
sonic boom.
The friction between the rock and the air is so intense that “it doesn’t
even burn it up, it vaporises,” said Tim Spahr, director of the Minor
Planet Center at Harvard University.
Wasson said one meteorite was found near the town of Coloma, northeast of
Sacramento. “I’m sure more will be found, I’m hoping, including some
fairly big pieces,” he said.
“The fact that two pieces already have been found means one knows where
to look,” Wasson said.
Bits of the meteor could be strewn over an area as long as 10 miles, most
likely stretching west from Coloma, where James W. Marshall first discovered
gold in California, at Sutter’s Mill in 1848.
Robert Ward of Prescott, Arizona, who has been hunting and collecting
meteorites around the world for more than 20 years, said he found the first
piece about 10am. Tuesday in between a baseball field and park on the edge
of the town of Lotus.
Ward said he “instantly knew” it was a rare meteorite known as “CM”
– carbonaceous chondrite – based in part on the “fusion
crusts from atmospheric entry” on one side of the rock. He actually has
two rocks that he suspects were part of the same small meteorite that split
on impact.
“It was just, needless to say, a thrilling moment,” he said.
“It is one of the oldest things known to man and one of the rarest types
of meteorites there is,” he said. “It contains amino acids and
organic compounds that are extremely important to science.”
Yeomens confirmed this type of meteorite is one of the more primitive types of
space rocks out there, dating to the origin of the solar system 4 to 5
billion years ago. And it’s “actually kind of unusual,” he said.
Yeomens said it’s got two of the most important chemicals that scientists look
for: carbon and a form of water. In fact, this type of space rock is likely
full of water and would have made a good candidate for the new space company
announced Tuesday that plans to mine asteroids, he said.
“And this one landed in their backyard for a lot less than they planned
to spend,” he said.
The minivan sized asteroid wasn’t on NASA’s lengthy list of near Earth objects
that they track coming close to the planet, so it took scientists by
surprise. “There are millions of objects of that size that we don’t
know about,” he said. “They’re too small to image unless they’re
right up on top of you.”
Ward and others tracked the meteorites’ possible location based on estimates
by, among others, scientists with the Meteor Group at the Western University
of Ontario in Canada that the fireball likely had exploded in the upper
atmosphere above California’s Central Valley.
Wasson suspected hundreds of dealers and collectors already have joined the
search. He said it was important to recover the meteorites soon because any
rain will cause them to degrade, losing their sodium and potassium.
“From my viewpoint as a meteorite researcher,” he said, “I’m
hopeful some big pieces are found right away.”
Source: agencies
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