Short Wave

‘Black rain’ in Iran and the environmental cost of war

US-Israeli airstrikes on oil depots culminated in ‘black rain’ in Iran early last week – a phenomenon usually caused by large amounts of soot, carbon and other pollutants in the air. Usually, rain leaves the atmosphere cleaner than it was before. But in this case, the rain left Tehran’s residents with sore throats and burning eyes. Oily, sooty residue was all over the city. So, we talked to an environmental pollution expert to find out: What’s in this ‘black rain’, what are its potential short- and long-term environmental and health effects, and what could recovery look like?Interested in more science behind current events? Email us your question 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.To manage podcast ad preferences, review the links below:See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy

This is your brain on pleasure (even the guilty kind)

It’s likely you have at least one “guilty pleasure.” Maybe it’s romance novels. Or reality TV… Playing video games… or getting swept into obscure corners of TikTok. Neuroscientists say the pleasure response helps us survive as a species. So why do we feel embarrassed by some of the things we love the most? Even if you don't have these negative emotions, experiencing – and studying – pleasure is not as straightforward as it might seem. For a long time, neuroscientists thought the concept of "pleasure" referred to a singular system in the brain. But as research into the subject grew, scientists realized that pleasure is really a cycle of "wanting" and "liking" – each with separate neural mechanisms. Today on the show, producer Rachel Carlson explores this cycle with researchers, who weigh in on the science of pleasure. Even the kind that makes us feel guilty. Read more of Rachel’s story on guilty pleasures. Interested in more brain science? Email us your question 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.To manage podcast ad preferences, review the links below:See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy

An icy mystery: What are lake stars?

When producer Berly McCoy was out on her local frozen lake, she saw something she'd never seen before. There were dark spidery, star-shaped patterns in the ice and they freaked her out. So, we called an expert to find out more about them. In today’s episode, geophysicist Victor Tsai tells us about lake stars and how he became the first person to scientifically prove how they form. Plus, he explains how knowing more about lake stars can potentially give us clues about the presence of water on Europa, one of Jupiter’s icy moons.Read Victor Tsai’s full paper on lake stars here.Have a question about something in the environment? 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. To manage podcast ad preferences, review the links below:See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy

We saved gray whales from extinction. Why are so many dying again?

In 1999 hundreds of gray whales washed up along the west coast of North America. More in 2000. They lost an estimated 25% of their population. But then the whale population recovered and people moved on. Until it happened again in 2019. And 2020, and 2021. It’s still happening today. Host Regina G. Barber dives into this mystery with marine ecologist Joshua Stewart, who explains how scientists like himself solved it – and the tough questions that came up along the way. Check out our Sea Camp series and our limited run Sea Camp newsletter, featuring deep dives into research, cute critters and games!Interested in more ocean mysteries? Email us your question 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. To manage podcast ad preferences, review the links below:See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy

Sibling order may affect sexuality and identity

Today, guest host Selena Simmons-Duffin is exploring a detail very personal to her: How the number of older brothers a person has can influence their sexuality.Scientific research on sexuality has a dark history, with long-lasting harmful effects on queer communities. Much of the early research has also been debunked over time. But not this "fraternal birth order effect." The fact that a person's likelihood of being gay increases with each older brother has been found all over the world – from Turkey to North America, Brazil, the Netherlands and beyond. Today, Selena gets into all the details: What this effect is, how it's been studied and what it can (and can't) explain about sexuality.Interested in the science of our closest relatives? Check out more stories in NPR's series on the Science of Siblings.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.To manage podcast ad preferences, review the links below:See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy