Dinosaur-killing asteroid: Chicxulub caused rapid global cooling


dinosaurs asteroid strike impact extinction event global disaster shutterstock_408550594
An
illustration of asteroids striking Earth during the age of
dinosaurs.


Shutterstock


  • A city-size asteroid or comet is thought to have killed
    the dinosaurs 66 million years ago.
  • The impact, called the Chicxulub event, released
    unfathomable quantities of dust and gas, rapidly cooling the
    entire planet.
  • The angle of impact was recently recalculated,
    and

    computer models suggest that means the
    event led to a global cooling disaster far worse than
    previously estimated.

Fighters may prefer to land straight-on punches, but when it
comes to asteroid and comet impacts, scientists are discovering
that angled strikes can be far more dangerous.

The dinosaurs had a rough go when a
rogue space rock
the size of a city struck Earth 66 million
years ago, near what is now the city of Chicxulub on Mexico’s
Yucatán Peninsula.

Until recently, researchers thought the asteroid or comet hit
nearly straight-down 90-degree angle, but recent drilling
expeditions at Chicxulub crater (at the bottom of the Gulf of
Mexico) suggest it happened at a more stilted 60-degree angle.

Scientists already knew that the impact — called the Chicxulub
event — released an amount of energy roughly equivalent to 40,000

US nuclear arsenals
in a matter of seconds, triggering a
terrifying chain of events. The blast ignited global firestorms,
blew hurricane-force winds for thousands of miles, crushed
coastlines with massive tsunamis, and shook the entire planet,
leading to massive landslides and earthquakes around the globe.

Some now-extinct species might have survived these calamities,
however, were it not for a more drawn-out killer: global cooling.
The dust and gases released into the upper atmosphere by the
impact reflected much of the sun’s energy back into space for
years. This dramatically chilled the planet, the leading theory
goes, leading to
the Cretaceous-Paleogene extinction event
, in which some 75%
of lifeforms perished.


asteroid meteorWikimedia Commons/NASA

According to a study published
Monday
in Geophysical Research Letters, new computer
simulations using the recently revised angle suggest the
Chicxulub event released more than three times more
climate-cooling sulfur gas than previously thought.

“We wanted to revisit this significant event and refine our
collision model to better capture its immediate effects on the
atmosphere,” Joanna Morgan, a geophysicist at Imperial College
London, said in an American Geophysical Union press release.

The model Morgan and her colleagues created suggests that the
sulfur gas from vaporized rock and seawater could have dropped
global surface temperatures by an average of nearly 47
degrees Fahrenheit almost overnight. Such temperatures may have
lasted for several years, until most of the aerosolized sulfur
fell out of the sky.

But sea life may have suffered much longer. It may have taken
“hundreds of years after the Chicxulub impact” for oceans to
rewarm, according to the study.

“These improved estimates have big implications for the climactic
consequences of the impact, which could have been even more
dramatic than what previous studies have found,” Georg Feulner, a
climate scientist at the Potsdam Institute for Climate Impact
Research, said in the release.

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