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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