Şenel and colleagues reported in Nature Geoscience in 2023 that fine silicate dust, 0.8 to 8 micrometers, excavated from the Tanis deposit in North Dakota, could have lingered in the atmosphere for up to 15 years, cooled the surface by as much as 15 degrees Celsius, and shut down photosynthesis for almost two years. The 2026 nickel paper adds that a dry CO impactor would deliver roughly half the sulfur that CM-based models assumed.
The popular image stayed nuclear winter, but older: a fireball, then sulfur darkness. The dust revision barely made headlines, because a fireball is filmable and rock flour is not. Public understanding of the extinction is now two mechanism-upgrades behind the literature.
The mechanism that survived scrutiny is the least cinematic one: inert rock powder hanging in the stratosphere, switching off the sun by particle size. The most violent day in the history of life killed by the most boring possible means, dust motes with a fifteen-year half-life.
If the mechanism was wrong for two decades while the crater sat fully measured, how settled is any extinction story?