What if the space rock that wiped out the dinosaurs, hit a different place on Earth?
(Esteban De Armas/Shutterstock)
The era of the dinosaurs met an unlikely end for had the cosmic impact that doomed it hit almost anywhere on the planet, the “terrible lizards” may still roam the Earth, a new study found.
The impact of an asteroid about 6 miles (10 km) wide, approximately 66 million years ago created a crater more than 110 miles (180 km) in the vicinity of what is now the town of Chicxulub (CHEEK-sheh-loob) in mexico’s Yucatan Peninsula. The meteor strike would have released as much energy as 100 trillion tons of TNT, more than a billion times more than the atom bombs that destroyed Hiroshima and Nagasaki together. The blast is thought to have ended the age of dinosaurs, the killing of more than 75 percent of all land-and sea creatures.
Prior work suggested the Chicxulub impact lofted enormous amounts of ash, soot and dust into the atmosphere, choking the amount of sunlight reaching the earth’s surface by as much as 80 percent. This would have caused earth’s surface to cool down quickly, which leads to a so-called “impact winter” that would have killed plants, leading to a global collapse of terrestrial and marine food webs. [Wipe Out: History’s 7 Most Mysterious Extinctions]
To explain why the Chicxulub impact winter turned out to be so catastrophic, Japanese scientists earlier suggested the superhot debris from the meteor strike is not only caused forest fires on the other side of the planet, but also ignited stones loaded with hydrocarbon molecules, such as oil. They have calculated that such fat rocks would have generated large amounts of soot.
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The amount of hydrocarbons in the rocks varies greatly, depending on the location. In the new study, the Japanese researchers analysed the places on Earth where an asteroid impact could have happened to cause the level of destruction seen with the Chicxulub event.
The scientists believe the asteroid that wiped out the dinosaurshappened to hit an unfortunate spot — had it landed in about 87 percent of anywhere else on Earth, the mass extinction would not have occurred.
“The chance of mass extinction occurring was only 13 percent,” said study lead author Kunio Kaiho, a geochemist at Tohoku University in Sendai, Japan.
The scientists ran computer models to simulate the amount of soot that asteroid impact would have generated, depending on the amount of hydrocarbons in the ground. The following estimate of the climate effects caused by these different impact scenarios.
The researchers calculated the level of climate change required for a mass extinction, was a 14.4 and 18 degrees Fahrenheit (8 to 10 Celsius degrees) drop in the global average surface temperature. This would involve a asteroid impact to send of 385 million tons (350 million tonnes) of soot in the stratosphere.
The scientists discovered that a mass extinction would have occurred from the impact only if it had hit 13 percent of the surface of the Earth, including both land and oceans. “If the asteroid had hit with a low to medium level, hydrocarbon field on Earth, and covers about 87 percent of the surface of the Earth, the mass extinction would not have occurred,” Kaiho told Live Science.
The scientists are also analyzing the level of climate change caused by the large volcanic eruptions that may have contributed to other mass extinctions,” Kaiho said. “It is hoped that the results will lead to more insight in the processes behind this mass extinction.”
Kaiho and his fellow Naga Oshima at the Meteorological Research Institute in Tsukuba, Japan, detailed their findings online today (Nov. 9) in the journal Scientific Reports.
Original article on Live Science.