- DENVER (AP) -- The phone lines to Denver's Museum of Natural History have
been buzzing since a fireball streaked across the Colorado sky last month.
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- That flash of light, caught on a homeowner's
security camera, was not an isolated incident; it was followed by at least
four more fireball sightings, said Jack Murphy of the museum's geology
department. He hopes to find pieces of the celestial objects for the museum's
collection.
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- As new reports of sightings keep coming
in, scientists are debating the meteorites' origin and the meaning of the
increased activity. There is more at stake, they say, than where a piece
of rock fell to the ground.
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- "These little things are the little
brothers and sisters of the bigger ones," said Doug Revelle, a scientist
at Los Alamos National Laboratory. "The reason for the interest is
eventually a big one is going to hit, a real big one. And the question
is: Can we protect ourselves?"
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- If a large meteor hit Earth, "life
as we know it would be very different," he said.
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- When a fireball fell into the Earth's
atmosphere on Jan. 11, a Front Range resident's home security camera documented
the bright light and shadows along with the sonic boom caused by the apparent
meteorite, Revelle said.
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- Scientists will use the time between
the flash and boom -- 132 seconds -- to help determine where the meteorite
touched down, assuming it didn't burn out before landing.
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- Then, at about noon on Jan. 27, a commercial
airline pilot flying over Wyoming spotted "a ball of flame trailing
smoke."
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- "He reported he did get some turbulence
from the object," Jim Patton, operations supervisor for the Federal
Aviation Administration's flight service center in Casper told the Rawlins,
Wyo., Daily Times. "He saw the debris and felt the shock wave from
it."
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- Residents in Breckenridge, Colo., also
reported seeing that daytime fireball. Murphy said they believe the space
rock was heading south to north and landed just north of Hanna, Wyo.
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- That night, another fireball broke into
the Earth's atmosphere.
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- Scientists believe that meteorite came
down in southern Colorado or northern New Mexico, Murphy said. People in
Breckenridge spotted that fireball, too.
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- "That one was seen traveling east
to west," Murphy said. "It has been a long time since we've seen
one moving like that."
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- Another meteorite was seen and heard
at sunrise in eastern Colorado on Jan. 30. And Murphy is investigating
a report that came in earlier this month.
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- So what's happening?
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- "I don't know," Murphy said.
"We can't attribute it to anything. But it is unusual to have so much
activity."
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- University of Denver astronomer Robert
Stencel suggested that Earth may be getting pelted with pieces of the Hale-Bopp
comet. Early in January the Earth passed through the part of space the
comet had traveled.
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- "Comets are like kids with muddy
boots," Stencel said. "They leave a trail of debris in their
wakes."
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- Meteorites from asteroids breaking out
of the orbital belts between Mars and Jupiter are made up of metals, mostly
iron. A meteorite from a comet would have a lighter element composition,
Stencel said.
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- Such space debris is rare and would be
of great scientific value, he said. Scientists will test the composition
of the meteorites -- if they can get their hands on them.
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- Revelle said he's excited about the meteorite
activity, but he can't account for it.
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- The reports describe a smoke trail following
the fireballs -- or bolides, which are exploding meteors.
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- "The smoke trail is an indication
that the object was quite big and strong," Revelle said. "Over
the globe we see objects that are about a meter across an average of only
12 times a year."
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- Last Oct. 10, a meteorite crashed near
West Texas and New Mexico; then on Dec. 9, a large fireball crashed near
Greenland, and on Dec. 13, a meteorite was seen across hundreds of miles,
from Minnesota and Wisconsin south into Iowa and northern Missouri.
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- Revelle said history may give us some
insight into the meaning of the increase in fireball activity.
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- About 60 million years ago, an asteroid
crashed into the Earth and kicked up enough dust to blot out the sun. Some
scientists believe this resulted in the death of more than 80 percent of
all animals and led to the extinction of dinosaurs.
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- "These events seem to occur every
60 million years, give or take 10 million," he said. "We're about
three million years short of 60 million.
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- "In order to defend the Earth from
a large meteor, we would need to know about it while it was months away
to deflect it," he said. "If we knew about it when it was weeks
away, it would be too late."
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