In the 1970s in the town of Gubbio, Walter Alvarez discovered traces of an asteroid; his discovery led to the theory that the asteroid hit Earth during the Cretaceous period and caused the mass extinction of dinosaurs. This aligned with the catastrophist interpretation; although it was meant with initial skepticism, it explained the disappearance of forams in lower limestone layers, the high iridium levels, & the questions of what happened to the dinosaurs. Evidence for the theory accumulated as shocked quartz, sandstone from a tsunami, & a large crater was found.
Alvarez later declared that the “truly catastrophic effect of the asteroid…was the dust” by rapidly moving around the Earth and blocking the sun for weeks, killing ¾ of Earth's species and causing a global winter. I connected this to an article I read about a solution to global warming: asteroid dust; although it wouldn't be a permanent cure, the dust could block sunlight and cool the Earth while letting carbon capture take effect. Even so, the asteroid would be a safety concern to humans and other species.
When Kolbert visited Princeton to see the consequences of the asteroid, ammonites were a key example; ammonites were a thriving species capable of surviving in different temperatures until the asteroid decimated their population. Overall, this chapter connects to the theme that science changes our understanding of the world. Prior to Alvarez's theory, it was thought that extinction and natural selection were gradual processes. However, the arrival of the asteroid made survival difficult and emphasized the differences between catastrophism and uniformitarianism; this shift in thinking represents how scientific thinking can evolve.
Attached is a reenactment of the dinosaurs extinction. https://www.youtube.com/watch?v=Y8Ij9xboreA
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