For over forty years, Dutch geologist and paleontologist Jan Smit has been at the center of one of the most profound scientific detective stories of our time: the investigation into the mass extinction that ended the reign of the dinosaurs 66 million years ago. Known as the Cretaceous-Paleogene (K-Pg) extinction, this event wiped out nearly 75% of all species on Earth, from towering dinosaurs to microscopic marine life, and cleared the way for the rise of mammals and, eventually, humans.
Early in his career, Jan Smit became intrigued by a thin layer of clay found in rock strata across the globe, precisely at the boundary between Cretaceous and Paleogene sediments. This layer, unusually rich in the rare element iridium, held clues that would eventually transform our understanding of planetary history. Working alongside Luis and Walter Alvarez and others, Jan helped develop the hypothesis that a massive asteroid impact, rather than volcanic activity or gradual climate change, was the primary cause of the extinction.
In this episode, we explore the extraordinary evidence for that theory: global patterns of shocked quartz, tsunami deposits, a massive crater buried beneath the Yucatán Peninsula, and the sudden disappearance of entire ecosystems in the fossil record. Jan walks us through decades of fieldwork and analysis that revealed the incredible violence and planetary consequences of the impact, a blast more powerful than a billion Hiroshima bombs, throwing Earth into a global winter.
But this is more than a forensic tale of catastrophe. It's a window into the fragility and resilience of life, the interconnectedness of geological and biological systems, and the awe-inspiring forces that shape the story of our planet.
Watch on Youtube:
https://youtu.be/YOlOuBYgAmQ
