Episode Details

The Space Show with Dr. Gerta Keller for Sunday, Sept. 14, 2025 are ready!

This Space Show program featured guest Dr. Gerta Keller, a paleontologist and geologist from Princeton, who has challenged the traditional asteroid impact theory for dinosaurs' extinction, presenting evidence that volcanic activity from the Deccan Traps in India was the primary cause. Our discussion concluded with an exploration of the scientific debates surrounding dinosaur extinction theories, including the role of climate change and the implications for understanding current environmental

challenges.

Dr. Keller, a professor emeritus of paleontology and geology at Princeton, shared her journey from a childhood in poverty to becoming a leading expert on mass extinctions and impact events. She discussed her unconventional path, including traveling the world during wars and surviving a shooting, before eventually pursuing a career in science. Dr. Keller's research challenges the traditional asteroid impact theory for the extinction of dinosaurs, proposing instead that volcanic activity played a significant role. The Space Show audience was introduced to her work and invited to learn more about her findings and career.

In more detail, Dr. Keller shared her remarkable journey from a young girl loving to read in Switzerland to becoming a pioneering paleontologist and geologist. She described her early life, education, and travels, including her experiences during the Flower Child era in San Francisco. Gerta's academic career took her from SF City College to Stanford and Princeton, where she worked on microfossils and climate change. She eventually returned to her interest in dinosaurs and challenged the widely accepted theory that an asteroid impact caused the dinosaurs' extinction. Gerta's research suggested that volcanic activity and climate change played a significant role in the fifth mass extinction, challenging the Alvarez hypothesis.

Dr. Keller discussed her discovery of impact glass spherules from multiple asteroid impacts during the Eocene, approximately 38 million years ago, which contradicted the widely accepted theory that a single asteroid impact caused the Cretaceous-Paleogene extinction event 66 million years ago. She explained that her research, which included finding pristine 2-meter thick layers of impact glass in Mexico, was initially rejected by peer reviewers for 10 years before being published in 1983. The discovery led to a heated debate at a major conference in Nice, France, where Keller presented evidence of multiple impacts, while others argued for a tsunami theory.

Gerta discussed her research challenging the asteroid impact theory for the KT boundary event, presenting evidence that the iridium anomaly could instead be explained by volcanic activity. She described how her work with a NASA Astro chemist and their student revealed that the iridium was actually from water-suspended material, not an asteroid impact. Gerta also shared her findings from extensive drilling in India, where she discovered that massive Deccan Traps volcanic activity occurred rapidly and had a significant global climate impact, supporting his theory that volcanic activity rather than an asteroid caused the mass extinction.

Dr. Keller explained that the Deccan Traps volcanic activity, not the Chicxulub impact, caused the dinosaurs' extinction. She described how the volcanic eruptions led to gradual global warming over millions of years, which eventually caused the extinction by making dinosaur eggs unviable due to thickened shells. She emphasized that her theory has been competing with the impact theory for decades, but recent evidence supports her volcanic hypothesis. She noted that while the Chicxulub impact occurred 200,000 years before the mass extinction, it was not the cause.

Keller discussed the Cretaceous-Paleogene (KP) extinction event, emphasizing that while the Ch