Chicxulub dust models point to lethal heat pulse after dinosaur-killing impact

A paper in the Journal of Geophysical Research: Biogeosciences argues the Chicxulub asteroid impact about 66 million years ago lofted fine dust that superheated the upper atmosphere, charbroiling exposed organisms and helping ignite widespread wildfires, Ars Technica reported. Prior work focused on spherules of condensed rock vapor that fall back and deliver a brief heat pulse, long thought too mild alone to roast animals or spark global fires. Co-author Brandon Johnson of Purdue University pointed to 2023 evidence of an extremely fine post-impact dust layer that may have formed from leftover rock vapor. Once models included that dust, Ars Technica reported the team found organisms would have been blasted with 17 times more thermal radiation than earlier spherule-only estimates, with Johnson saying the result puts survivors in the realm of being killed within about the first hour or two if they could not take shelter. The impact site is the Chicxulub crater on Mexico's Yucatan Peninsula. The impactor is estimated between 11 and 81 kilometers across and would have released energy more than a billion times that of the Hiroshima and Nagasaki bombs, Ars Technica summarized from prior research.