© By Dbot3000 - Own work, CC BY-SA 4.0,Wikimedia OrgThis photo of comet C/2020 F3 NEOWISE was taken in July 2020. There's no doubt that comets have struck Earth in the past, and some have exploded in the air above the surface. One of these exploding comets could've triggered the Younger Dryas, bringing and end to the Clovis culture and wiping out megafauna.
There are many other large potential impactors that explode above the surface, called touchdown airbursts, and their effect on Earth is much harder to quantify. New research suggests that a swarm of debris from an exploding comet left its mark by triggering the Younger Dryas, a period of abrupt cooling around 12,000 years ago. The researchers say that the touchdown airburst and the resulting Younger Dryas led to the extinction of megafauna, and the disappearance of the Clovis culture.
Their findings support the Younger Dryas Impact Hypothesis (YDIH) which states that the impact of a disintegrating asteroid or comet is responsible for abruptly cooling the Earth. The YDIH isn't widely accepted in the science community. Critics tout the lack of an impact crater as evidence against the YDIH. They also say that other evidence supporting it can best be explained by other causes.
New research found evidence of comet debris impact at sites of the Clovis culture, a culture that came to an end at the same time as the Younger Dryas. Will this new research lead to wider acceptance of the YDIH?
The research appears in PLOS One. It's titled "Shocked quartz at the Younger Dryas onset (12.8 ka) supports cosmic airbursts/impacts contributing to North American megafaunal extinctions and collapse of the Clovis technocomplex," and the lead author is James Kennett. Kennett is the UC Santa Barbara Emeritus Professor of Earth Science.
