Short Wave

At least, it's contagious among a group of captive chimpanzees at the Kumamoto Sanctuary. How do researchers know? A very dedicated grad student at Kyoto University. In the quest for scientific knowledge, Ena Onishi logged over 600 hours in the field! This episode, host Regina G. Barber and special guests Jonathan Lambert and Ari Shapiro get into the nitty gritty of the research and their hypotheses for why this is happening in this episode. Read Jonathan's full reporting about contagious peeing in chimps. Delighted by other scientific discoveries you think we should share with the whole class (the rest of our audience)? Let us know by emailing shortwave@npr.org! Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

Around the turn of the century, 3.8 million people banded together in a real-time search for aliens — with screensavers. It was a big moment in a century-long concerted search for extraterrestrial intelligence. So far, alien life hasn't been found. But for people like astronomer James Davenport, that doesn't mean the hunt is worthless — or should be given up. No, according to James, the search is only getting more exciting as new technology opens up a whole new landscape of possibilities. So today on the show: The evolving hunt for alien life. Want more space content? Let your opinion be heard by dropping us a line at shortwave@npr.org! Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

Forests are the lungs of our planet. Not only do they absorb carbon dioxide and create oxygen, they also regulate temperature, absorb rainwater to help prevent flooding, and provide critical habitat for the majority of the world's land-based plant and animal species. But due to land conversion for agriculture and road construction, timber harvesting, and increasing wildfires, the trees that make up our forests are increasingly endangered. That's why we need reforestation: replanting new forests to replace the old ones. For the past century, the United States Forest Service has helped to replant new forests and manage existing ones. But as scientists face the ongoing threat of climate change, they're developing new strategies... including one that tries to literally predict the future. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

On Wednesday, the Food and Drug Administration announced it is banning the dye called Red No. 3, a food dye additive in many processed foods, like sodas, sweets and snacks. Recently, it and other dyes were linked to behavior issues in children. But high levels of Red No. 3 were linked to cancer in rats decades ago. So why is the ban happening now? Senior editor and science desk correspondent Maria Godoy answers our questions about Red No. 3 and other dyes that may replace it. Plus, how should parents think about feeding their kids products that may contain Red No. 3 before the ban takes affect. Questions, story ideas or want us to dig into another food science issue? Email us at shortwave@npr.org — we'd love to hear from you! Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

Imagine the tree of life. The tip of every branch represents one species, and if you follow any two branches back through time, you'll hit an intersection. If you keep going back in time, you'll eventually find the common ancestor for all of life. That ancestor is called LUCA, the last universal common ancestor, and there is no fossil record to tell us what it looked like. Luckily, we have Jonathan Lambert. He's a science correspondent for NPR and today he's talking all things LUCA: What we think this single-celled organism may have looked like, when it lived and why a recent study suggests it could be older and more complex than scientists thought. Have other questions about ancient biology? Email us at shortwave@npr.org — we'd love to hear from you! Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

When you picture a dinosaur, what does it look like? For Jingmai O'Connor, paleobiologist and associate curator of reptiles at the Field Museum of Chicago, the dinosaurs she studies look a lot more like birds. "If you looked at an artist's reconstruction of something like Velociraptor or Microraptor ... you would see that it pretty much looks the same as a bird," Jingmai says. "In terms of the plumage, the soft tissues covering the body, it would have looked very, very birdlike." In this episode, Short Wave delves into the dinosaur-avian connection. Which dinosaurs had feathers? Were they using them to fly? And once and for all – what are those ancient dinosaurs' relationship to birds today? Have other dinosaur questions you want us to unravel? Email us at shortwave@npr.org — we'd love to hear from you! Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

The COVID-19 mRNA vaccine generates enough of an antibody response to protect against severe disease for six months. But other vaccines offer years-long — even lifelong — immunity, such as the measles or yellow fever vaccines. Is there a way for scientists to tell how long a person's immunity will last? A team at Stanford Medicine might have found a way to do just that — with the help of some of the cells found in our bone marrow. Questions about vaccines or the respiratory season? Email us at shortwave@npr.org — we'd love to hear from you! Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

Air quality in the Los Angeles region has plummeted due to smoke from the ongoing wildfires. With all that smoke comes possible risks to human health. So what actually is smoke and why is it so harmful? Jessica Gilman, an atmospheric chemist with the National Oceanic and Atmospheric Administration, explains what smoke is made of, how it behaves in the atmosphere and smoke's role in climate change. Plus, tips for how to lessen your exposure. Check out the CDC's recommendations for avoiding smoke inhalation here. Read more of NPR's coverage of the fires. Questions, story ideas or want us to dig more into the science underpinning natural disasters? Email us at shortwave@npr.org — we'd love to hear from you! Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

Over 29,000 acres in the greater Los Angeles area are on fire right now. The fires emerged after the Santa Ana winds swept into the Los Angeles area Tuesday. The largest is the Palisades fire, which is quickly burning through the Pacific Palisades and Malibu communities. It's one of four ongoing critical fires — only one of which is partially contained. Ahead of the windy week, a Red Flag Warning was issued for an increased fire risk due to the strong winds, low humidity and higher temperature. Today, we dig into the Santa Ana winds: What they are and how they combined with other factors to create conditions for the most destructive fire in Los Angeles' history. Questions, story ideas or want us to dig more into the science underpinning natural disasters? Email us at shortwave@npr.org — we'd love to hear from you! Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

Fluoridating the public water supply has been common practice for nearly 80 years in the U.S. It's an acclaimed public health intervention that helps prevent cavities. For just as long, some have raised concerns about the practice that can veer from evidence-based to unsubstantiated conspiracy. An analysis by government researchers, published Monday in JAMA Pediatrics, is adding to the debate. The research found that exposing babies and kids to high levels of fluoride might be associated with neurodevelopmental harm. Frankly, it's a lot to digest — so we invited health correspondent Pien Huang onto the show to wade through the debate. Questions, story ideas or want us to dig into another public health debate? Email us at shortwave@npr.org — we'd love to hear from you! Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

Some weapons used by the U.S. military are so powerful they can pose a threat to the people who fire them. Today, we meet two Marines, William Wilcox and Michael Lozano, who spent years firing missiles and rockets, then developed the same rare brain condition: arteriovenous malformation, or AVM. The condition sends high pressure blood from a tangle of abnormal blood vessels directly into fragile veins, which can leak or burst. Most AVMs are caused by genetic changes that affect the growth of blood vessels, so the connection between weapon blasts and AVM isn't always immediately clear. But NPR's brain correspondent Jon Hamilton reports that recent research suggests that blast waves can alter genes in the brain — and that the evidence is even stronger for less extreme blood vessel changes. Have questions or story ideas? Let us know by emailing shortwave@npr.org! Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

There are hundreds of atomic clocks in orbit right now, perched on satellites all over Earth. We depend on them for GPS location, Internet timing, stock trading ... and space navigation? Today on the show, hosts Emily Kwong and Regina G. Barber learn how to build a better clock. In order to do that, they ask: How do atomic clocks really work, anyway? What makes a clock precise? And how could that process be improved for even greater accuracy? For more about Holly's Optical Atomic Strontium Ion Clock, check out the OASIC project on NASA's website. For more about the Longitude Problem, check out Dava Sobel's book, Longitude. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. Have questions or story ideas? Let us know by emailing shortwave@npr.org! Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

Funeral services begin today for former President Jimmy Carter. He died Sunday, at 100-years-old. Carter brought attention to global health challenges, particularly "neglected" tropical diseases like Guinea worm. With reporter Jason Beaubien, we look at that decades-long effort and how science was central to Carter's drive for a better world. Questions or comments for us at Short Wave? Let us know by emailing shortwave@npr.org — we'd love to hear from you! Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

Snowflakes. These intricate, whimsical crystals are a staple of magical wintry scenes, but how big can they really get? Well, according to the Guinness World Record keepers, the "largest snowflake" ever recorded was a whopping 15 inches in diameter. It was spotted near Missoula, Montana in 1887. But Kenneth Libbrecht, a physicist at Caltech, has long been skeptical of that record. So he set out to find what makes a snowflake a snowflake and whether that 1887 record is scientifically possible. You can read more about what he discovered here. (encore) Want to share the snowflakes you've spotted this winter? Email us a photo at shortwave@npr.org. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

Happy New Year, Short Wavers! What better time to contemplate the conundrum that is zero than this, the reset of the year? Zero is a fairly new concept in human history and even more recent as a number. It wasn't until around the 7th century that zero was being used as a number. That's when it showed up in the records of Indian mathematicians. Since then, zero has, at times, been met with some fear — at one point, the city of Florence, Italy banned the number. Today, scientists seek to understand how much humans truly comprehend zero — and why it seems to be different from other numbers. That's how we ended up talking to science writer Yasemin Saplakoglu about the neuroscience of this number that means nothing. Read more of Yasemin's reporting on zero for Quanta Magazine. Plus, check out our episode on why big numbers break our brains. Thirst for more math episodes? Let us know what kind of stories you want to hear from us in 2025 by emailing shortwave@npr.org! Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

2024 was full of science news. There was a total solar eclipse, the Paris Olympics, elections in the United States and elsewhere, technological breakthroughs and many space launches. But perhaps above all, it was a huge year in health. So, today, we're talking through some of 2024's biggest health stories — from what's in our drinking water supply, to bird flu, obesity drugs and this year's record heat. They're also the stories we think will continue to be big in 2025. See you in the new year, Short Wavers! <3 Questions or suggestions for what else we should cover? Email us at shortwave@npr.org! Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

The thick-billed parrot is the only surviving parrot species native to the United States. These brightly colored birds once roamed across the American Southwest and as far south as Venezuela — but today, the only wild population remaining lives high in the forests of Mexico's Sierra Madre mountains. For years, conservation organizations like OVIS (Organización Vida Silvestre) and the San Diego Zoo Wildlife Alliance have been working on a multi-faceted conservation project to save these birds. Host Regina G. Barber and producer Rachel Carlson dive into the details of that project — and how tiny "bird backpacks" are helping to make it all happen. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

In pop culture, squirrels are often seen as jerky, excited critters on the hunt for nuts to stuff themselves with and tuck away for later. But squirrels are on the hunt for something a bit meatier in the California Bay Area. Their target: local voles. The entire process — from hunt to kill — was captured on video. Want to hear more biology stories? Let us know by emailing shortwave@npr.org! Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

In the early 20th century, a blight fungus wiped out most of the 4 billion American chestnut trees on the eastern seaboard. The loss was ecologically devastating. Short Wave host Emily Kwong dives deep into how scientists are trying to resurrect the American chestnut tree — and recent controversy over a plan to plant genetically modified chestnuts in the wild. Want to hear about more efforts to recover endangered or lost species? Let us know by emailing shortwave@npr.org! Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy

On Christmas Eve, scientists at field stations across Antarctica sing carols to one another...via shortwave. On today's episode, the Short Wave podcast explores shortwave radio. We speak with space physicist and electrical engineer Nathaniel Frissell about this Antarctic Christmas Carol tradition and his use of shortwave radio for community science. Read more about Santa Net, which connects children (known in the shortwave radio community as "little harmonics") with Santa. Want more tech stories? Let us know by emailing shortwave@npr.org! Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. Learn more about sponsor message choices: podcastchoices.com/adchoices NPR Privacy Policy