Winter is Coming

Throughline

NPR

Documentary, History, Society & Culture

4.7 • 15K Ratings

🗓️ 6 November 2025

⏱️ 53 minutes

🔗️ Recording | iTunes | RSS

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Summary

Late last month, President Trump announced that the United States would be restarting nuclear weapons tests after a break of over 30 years. We’ve since learned that they won’t be the explosive kind of tests, but this sent us down a rabbit hole — where we found a story about dinosaurs, Carl Sagan, and nuclear war. Because there was a moment in the not-so-distant past when we learned what drove the dinosaurs extinct... and that discovery, made during the Cold War, may have helped save humans from the same fate. This episode originally published in March 2025.

Guests:

David Sepkoski, Thomas M. Siebel Chair in History of Science at the University of Illinois and author of Catastrophic Thinking: Extinction and the Value of Diversity.

Owen Brian Toon, professor of atmospheric and oceanic sciences at the University of Colorado Boulder.

Alec Nevala-Lee, novelist, critic, and biographer and author of the forthcoming book Collisions: A Physicist's Journey from Hiroshima to the Death of the Dinosaurs.

Ann Druyan, co-writer and co-creator of the television series Cosmos: A Personal Voyage.

Andrew Revkin, science and environmental journalist.

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Transcript

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0:00.0	Support for NPR comes from NPR member stations and Eric and Wendy Schmidt through the Schmidt Family Foundation,
0:07.4	working toward a healthy, resilient, secure world for all on the web at theshmit.org.
0:14.5	Hey, it's Ramteen. A quick note before we start. While on a trip to Asia, President Trump announced that the United
0:22.0	States was restarting nuclear weapons tests after a break of 30 years. We've since learned
0:28.4	that they won't be the explosive kind of test, but it got us thinking about one of our favorite
0:33.1	episodes so far this year, all about the connections between nuclear war, the dinosaurs, the relationship
0:39.2	between a father and son, and the one and only, Carl Sagan. We bring you, Winter is Coming,
0:47.0	which despite the subject matter, actually really is a hopeful story.
0:53.3	Planet Earth, 66 million years ago. The moment just before the end. The end. I'm The wind tickles a patch of ferns.
1:20.2	The shadow of a pine leaf dances lazily over a footprint in the dirt.
1:28.0	Somewhere nearby, a lumbering beast stops mid-stride.
1:32.8	It's a hulking mass of a creature, three horns, teeth like shears,
1:37.3	and it swings its head down in a low arc, listening.
1:46.0	Then, A low arc, listening. Then suddenly.
1:53.0	A flash of light, thousands of times more blinding than the sun.
1:59.0	An asteroid.
2:00.0	The size of Mount Everest.
2:02.0	Enteres the Earth's atmosphere, moving incredibly fast.
2:07.0	Ten times faster than the fastest bullet from a rifle.
2:11.4	In the blink of an eye,
2:14.5	this asteroid will crash into Earth's surface on the edge of the ocean,
2:18.8	with an impact equivalent to 5,000 times.
	...

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