Lights Out: Asteroid Triggered Freezing Darkness That Killed Dinos

When a giant asteroid careened into Earth about 66 million years ago, the enormous collision led to the formation of an airborne "curtain" of sulfate molecules that blocked the sun's light and led to years of freezing cold and darkness, a new study finds.

The finding shows how these droplets, or aerosols, of sulfuric acid formed high in the atmosphere, and likely contributed to the deaths of 75 percent of all animals on Earth, including nonavian dinosaurs such as Tyrannosaurus rex and long-necked sauropods, the researchers said.

Earlier studies suggested that the dino-killing asteroid kicked up dust and debris that hung in the air and blocked sunlight in the short term. But by using computer simulations, the researchers of the new study showed how droplets of sulfuric acid contributed to long-term cooling.

Moreover, the sudden, drastic drop in temperature likely caused the surface of the oceans to cool, which would have massively disturbed the marine ecosystems, the researchers said.

"The big chill following the impact of the asteroid that formed the Chicxulub crater in Mexico is a turning point in Earth history," the study's lead researcher Julia Brugger, a climate scientist at the Potsdam Institute for Climate Impact Research (PIK) in Germany, said in a statement. "We can now contribute new insights for understanding the much debated ultimate cause for the demise of the dinosaurs at the end of the Cretaceous era."

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