How To Avoid The End of the World

Throughline

The episode explores the historical parallels between the asteroid-driven extinction of dinosaurs and the 20th-century discovery of 'nuclear

Key takeaways

• The K-T boundary contains significantly higher levels of iridium than expected, pointing to an asteroid impact.
• Luis Alvarez used trace element measurement techniques from physics to identify the extraterrestrial origin of the extinction event.

Main topics

• Dinosaur Extinction
• The Alvarez Hypothesis

Notable quotes

The amount of light that would get through would be a hundred millionth of the amount of light we normally see.

Conclusion

The episode illustrates how scientific awareness of catastrophic poten

Transcript preview

Speaker 1 (0:01) This election season, you can streamline your news intake with Up First. Our team of reporters and editors works overnight, so you can start every morning Speaker 3 (0:09) with three stories you need to know. In short episodes, 12-14 minutes long, to save you time and your sanity. Follow Up Speaker 1 (0:17) First on the NPR app or wherever you get your podcasts. Speaker 4 (0:23) Planet Earth, 66 million years ago. The moment just before the end. Speaker 4 (0:47) The wind tickles a patch of ferns. The shadow of a pine leaf dances lazily over a footprint in the dirt. Somewhere nearby, a lumbering beast stops mid-stride. It's a hulking mass of a creature, three horns, teeth like shears. And it swings its head down in a low arc, listening. And suddenly... A Speaker 5 (1:23) flash of light... Thousands of times more blinding than the sun. Speaker 4 (1:29) An asteroid. The Speaker 5 (1:30) size of Mount Everest. Speaker 4 (1:32) Enters the Earth's atmosphere, moving incredibly fast. Speaker 3 (1:37) Ten times faster than the fastest bullet from a rifle. Speaker 2 (1:42) In the blink of an eye, this asteroid will crash into Earth's surface on the edge of the ocean with an impact equivalent to 5,000 times. Speaker 5 (1:52) The combined destructiveness of the entire nuclear arsenal at the height of the Cold War. It Speaker 2 (1:58) burrows into the Earth 20 miles deep. Everything within 90 miles. Every living thing. Is instantly vaporized. But Speaker 4 (2:16) this is just the beginning of the end. Speaker 4 (2:24) A giant fireball. Speaker 5 (2:26) All of the rock and dust and gas. Speaker 4 (2:30) Climbs back up and up and up. Speaker 5 (2:33) All the way into space. Speaker 4 (2:34) And bursts. Speaker 5 (2:35) Bursts through the atmosphere. Speaker 4 (2:38) As the Earth below shakes violently. Speaker 5 (2:40) Magnitude 12 or 13 rippling the entire crust of the Earth. Speaker 4 (2:46) Triggering unimaginably high tsunamis. Speaker 5 (2:49) The real bummer was all of that material that got ejected into space began to fall back. Speaker 4 (2:59) Millions of tiny specks, each the size of a grain of sand, re-enter the atmosphere and catch fire again. Speaker 3 (3:08) This is like an uncountable number of shooting stars coming into the sky above you, heating the air and the rock. Speaker 2 (3:16) A sea of lava descending from the heavens, unleashing hell on Earth. Speaker 3 (3:21) If you want to see it, open up your oven, turn the broiler on, and look at the glow bar. In this case, the whole sky is glowing. There are no shadows, so you're not going to get away from it. Speaker 2 (3:32) Swaths of life, the culmination of millions of years of evolution. wilt under the broiler of asteroid debris. Forests catch fire. The air teems with ash and smoke. And then... comes winter. Speaker 5 (3:51) The soot that stayed in the atmosphere blocked out the sun. Speaker 2 (3:55) Blocked out the sun. Speaker 3 (3:57) The amount of light that would get through would be a hundred millionth of the amount of light we normally see. It effectively turned day into night. Temperatures fell below freezing over all the Speaker 5 (4:09) land. Speaker 2 (4:10) No light meant no food. Speaker 5 (4:12) Plants can't photosynthesize. The food chains in the ocean probably collapsed. To say that this was a challenging environment, you know, for life to survive and continue to evolve would be an understatement. Speaker 4 (4:28) It was the end of a world and the beginning of another. Speaker 4 (4:46) Here at ThruLine, we've been finding ourselves thinking about the end of the world a lot lately. What that might look and feel like. Partly because we now live in a world with almost daily reminders of how fragile life is. Climate change, nuclear weapons, and AI. We've heard people inside AI companies sounding the alarm that we could be barreling towards our own destruction. And just last week, while he was speaking at the United Nations, President Trump asked whether the United States would reach a deal with Iran to end the conflict or whether he should, quote, annihilate them. And it raised the question, was President Trump threatening to use nuclear weapons? It kind of feels like one way or another, we're engineering the asteroid that might destroy us one day. So we wanted to revisit this episode. Speaker 2 (5:36) What do dinosaurs have to do with any of that? Well, it turns out that for most of human history, no one had a clue that dinosaurs had walked to Earth before us or that they disappeared in a sudden flash. But Speaker 4 (5:49) there was a moment in the not-so-distant past when we learned what caused their extinction. And that discovery may have helped save humans from the same fate. That moment. is where we'll be taking you in this episode. I'm Rondabd El-Fattah. Speaker 2 (6:06) And I'm Ramteen Arablui. You're listening to ThruLine from NPR. Speaker 4 (6:11) Today, we're traveling deep inside the Earth's layers, up above the clouds as the first nuclear weapon is dropped, and all the way to the cosmos. Speaker 5 (6:21) Sometimes we can avoid the worst fate that we can imagine. Speaker 8 (6:30) Yes, hello, my name is Janice Beck. I live in Iwakuni, Japan. Trueline is one Speaker 3 (6:37) of the best, if not the best. I wait each week for a new episode, and I'm never disappointed. Speaker 8 (6:45) Keep Speaker 3 (6:45) on doing it, please. Speaker 8 (6:47) Thank you so much. Bye-bye. Speaker 7 (6:49) This message comes from WISE, the smart way to manage your money around the world. With WISE, you can send, spend, and receive money in over 40 currencies at the mid-market rate. Learn more at WISE.com. T's and C's apply. Speaker 5 (7:05) Public media is no longer federally Speaker 1 (7:07) funded, but the NPR network remains yours in service to and powered by you. Keep public media public with a donation today at donate.npr.org, and thank you. Speaker 4 (7:21) This fall, there are a lot of movies and TV shows on tap for you to see, and we're as excited for all of it to arrive as you are. On Pop Culture Happy Hour, we've got a guide to what's worth keeping on your radar. Listen Speaker 1 (7:34) via the NPR app or wherever you get your podcasts. Part one, 45,000 miles per hour. Speaker 4 (7:48) It was 1977. A geologist named Walter Alvarez was spending a summer in Gubbio, a town in Italy about halfway between Venice and Rome. It sits in a valley alongside a mountain, formed by a fault line. And what was once an ancient seafloor became exposed over time, so you can actually see inside the Earth and look at millions of years of the planet's history. Speaker 5 (8:14) So you can think of like a layer cake. Speaker 4 (8:16) This is David Sapkoski. He's a historian of science at the University of Illinois Urbana-Champaign and author of the book Catastrophic Thinking. His dad, Jack Sapkoski, was a prominent paleontologist around this time. Speaker 5 (8:30) The layer cake, going from the top being the most recent layers of the history of life all the way down to the earliest ones. Speaker 4 (8:38) Try to picture it. A swirl of colors, rusty orange, dull brown, chalk white, with fossilized creatures sprinkled throughout. Each layer is a different thickness, and Walter Alvarez was focused on one layer in particular, the K-T boundary. Speaker 5 (8:57) The K-T boundary had been well studied around the world. Speaker 2 (9:01) It's striking. A very thin layer of clay, much thinner than the others around it, with a distinctive dark, ashy color, kind of like coal. Below the K-T boundary is the Cretaceous layer, marking the age of dinosaurs. It's filled with shards of dinosaur bones and teeth, the outline of their footprints. And above the K-T boundary is the tertiary layer, marking the age of mammals. In that one, you won't see many dinosaur fossils. In fact, none. None. None. Given that, paleontologists had already figured out that the dinosaurs went extinct many millions of years ago, between the Cretaceous and tertiary layers. They didn't know how it happened or the amount of time it took. But they assumed Speaker 5 (9:49) natural selection was a really gradual process. The Speaker 2 (9:52) Darwinian view of the world, that over time, the strongest and brightest species went out. As a geologist, Walter wasn't really interested in dinosaurs. He was just trying to measure how long it had taken these layers of sediment to form. This would be a big breakthrough if he could figure it out. But nothing had worked so far. Until... Speaker 7 (10:18) One day, his father calls up with an idea that has just occurred to him. Speaker 4 (10:24) We'll get to that idea in a bit. But first, we need to take you on a little detour to learn more about Walter's father, Luis Alvarez. We promise it's going to be worth it. See, Luis Alvarez wasn't just some guy with an idea. He was a Nobel Prize-winning physicist. Speaker 7 (10:41) The most Walter ever said to me on the record was that he and his father were not close. You know, that's an exact quote. Speaker 4 (10:49) By the way, this is Alec Navala Lee. Speaker 7 (10:51) I am a novelist, critic, and biographer. His Speaker 4 (10:55) upcoming biography is about Louis Alvarez. And he says Walter and Louis weren't close because from the time Walter was born in 1940... His Speaker 7 (11:04) father was occupied elsewhere. Speaker 4 (11:16) It was the middle of World War II. American scientists were racing to build an atomic bomb before the Germans did. Louis, a young up-and-coming physicist, gets involved and helps the American team figure out the missing link to actually make the bomb detonate. And when the order comes down to use the bomb on Hiroshima, he volunteers to be on the plane. On Speaker 7 (11:38) the observation plane. Speaker 4 (11:40) Following closely behind the Enola Gay as it unleashed, for the first time in history, the power of a nuclear weapon onto a city of 350,000 people. Speaker 7 (11:54) When the bomb goes off, there's a flash of white light that comes from the cockpit. And so at that moment, he knows the bomb has gone off. Speaker 7 (12:06) The entire plane bounds upward when the shockwave from the bomb hits the plane. So they feel it. They feel that shockwave, even from the air. And you can see the mushroom cloud. But when he looks down, he thinks that they've missed. It's so empty that he thinks that they missed entirely. Speaker 4 (12:30) Peering out the plane window at the devastation wrought by a bomb they'd named Little Boy, the gravity of what just happened begins to dawn on Louis. And then his mind turns to his own little boy, Walter, who was four years old at this point. Louis pulls out a pen and paper and begins writing him a letter. Speaker 8 (12:51) Dear Walter, this is the first grown-up letter I've ever written to you. It was really for you to read when you were older. During the last few hours, I've been thinking of you and your mother and our little sister Jean. It was tough to take off on this flight, not knowing whether I would ever see any of you again. Speaker 7 (13:15) It's partially an account of what happened that day. But he's also trying to, like, get his thoughts together about what it means to use this bomb. Speaker 8 (13:24) A single plane, disguised as a friendly transport, can now wipe out a city. Speaker 7 (13:30) He's trying to, in some ways, justify it to himself. Speaker 8 (13:34) What regrets I Speaker 7 (13:35) have. This is kind of like the paragraph that I come back to a lot. What regrets I have about being a party to killing and maiming thousands Speaker 8 (13:44) of Japanese civilians this morning are tempered with the hope that this terrible weapon we have created may bring the countries of the world Speaker 7 (13:52) together and prevent further wars. Speaker 8 (13:54) Alfred Nobel thought his invention of high explosives, Speaker 7 (13:58) dynamite, you know, Nobel's invention, would Speaker 8 (14:00) have that effect by making wars too terrible. But unfortunately, it had just