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By Robert Roy Britt Senior Science Writer Space.Com
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| The moment of impact 65 million years
ago near what is now the Yucatan Peninsula ... |
Artist's renderings courtesy of
NASA
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| ... and the Chicxulub crater, a few
days later. Note the inner ring. |
WHAT
HAPPENED
When
a giant space rock slammed into Earth 65 million years ago
near the present-day village of Chicxulub on the Yucatan
Peninsula, not only did it wipe out a lot of dinosaurs,
it left behind a huge crater and, inside that pock, an even
bigger mystery.
A tourist
in the jungle outside Chicxulub, about 200 miles (322 kilometers)
west of Cancun, wouldn't see any evidence of the crater,
now buried in eons of sediment. And she wouldn't suspect
she was standing more than a half-mile (1 kilometer) above
the center of the crater.
But
scientists found the crater a decade ago using seismic monitoring
equipment designed to hunt for oil. And now they have created
an animated computer model that shows how the crater might
have formed -- and how it would have left behind an otherwise
inexplicable inner ring.
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A new computer model shows a 5-10 minute event
during which the crater collapsed inward, forcing
up a central mound that soared three times the height
of Mount Everest. It then collapsed down and out to
produce the inner ring.
NOTE: Vertical scale is enlarged.
Animation courtesy of Gareth Collins
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The
collision
A comet
or asteroid the size of a small city rocked the lanet, sending
giant tsunamis across the ocean and earthquakes reverberating
around the globe. It also turned much of the Yucatan into
mush, scientists suspect, causing rock to behave like a
thick fluid.
The
animation of the Chicxulub event shows how the whole thing
might have happened, right up to the part where the ring
mysteriously solidifies, like terrestrial Jell-O in some
standard crater mold.
The
ring can't be explained. Similar rings have been observed
inside other craters on Earth and elsewhere in the solar
system.
Clues
to dino death?
The
Chicxulub impact is widely believed to have triggered a
mass dinosaur die-off, either through a global firestorm
or through massive long-term environmental changes.
Figuring
out how such a ring might form would help researchers understand
the chemical and physical processes that go on during an
impact, and whether and how such events might have caused
mass extinctions in the past.
"This
kind of research is crucial if we want to understand the
environmental knock-on effects of giant impacts," said
Benny Peiser, a researcher who focuses on neo-catastrophism
at Liverpool John Moores University. "The truth of
the matter is that despite 20 years of impact research,
we are still far from knowing even the main mechanisms of
impact-related mass extinctions."
Such
research could also help humanity prepare for the effects
of any possible future impacts, and it might also shed light
on how plain old earthly landslides occur.
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