500 million years ago, the world was a very different place. During this period of time, known as the Cambrian period, basically all life was in the water. The ocean was brimming with animals that looked pretty different from the ones we recognize today — including a group of predatory worms with a throat covered in teeth and spines. Researchers thought these tiny terrors died out at the end of the Cambrian period. But a paper published recently in the journal Biology Letters showed examples of a new species of this worm in the fossil record 25 million years after scientists thought they'd vanished from the Earth. One of the authors of the paper, Karma Nanglu, tells us how this finding may change how scientists understand the boundaries of time. Curious about other weird wonders of the ancient Earth? Email us at shortwave@npr.org.Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy

We've all been there: You sit down for one episode of a reality TV show, and six hours later you're sitting guiltily on the couch, blinking the screen-induced crust off your eyeballs. Okay. Maybe you haven't been there like our team has. But it's likely you have at least one guilty pleasure, whether it's playing video games, reading romance novels or getting swept into obscure corners of TikTok. It turns out that experiencing – and studying – pleasure is not as straightforward as it might seem. And yet, pleasure is quite literally key to the survival of humanity. So today on the show, we explore the pleasure cycle: What it is, where it lives in the brain and how to have a healthier relationship with the things that make us feel good. Want more on the brain? Email us the neuroscience you want us to talk about at shortwave@npr.org! (Also please email us if you would like to gush about any of the books you've been loving — romantasy or otherwise!)Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy

Wednesday the Environmental Protection Agency announced new drinking water standards to limit people's exposure to some PFAS chemicals. For decades, PFAS have been used to waterproof and stain-proof a variety of consumer products. These "forever chemicals" in a host of products — everything from raincoats and the Teflon of nonstick pans to makeup to furniture and firefighting foam. Because PFAS take a very long time to break down, they can accumulate in humans and the environment. Now, a growing body of research is linking them to human health problems like serious illness, some cancers, lower fertility and liver damage. Science correspondent Pien Huang joins the show today to talk through this new EPA rule — what the threshold for safe levels of PFAS in tap water is, why the rule is happening now and how the federal standards will be implemented.Read more of Pien's reporting on the EPA's first ever rule on PFAS in drinking water.Want to hear more about health and human safety? Email us at shortwave@npr.org — we might cover your question on a future episode!Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy

It's National Siblings Day! To mark the occasion, 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 reading more about the science surrounding some 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.Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy

It's baseball season! And when we here at Short Wave think of baseball, we naturally think of physics. To get the inside scoop on the physics of baseball, like how to hit a home run, we talk to Frederic Bertley, CEO and President of the Center of Science and Industry, a science museum in Columbus, Ohio. He also talks to host Regina G. Barber about how climate change is affecting the game. Interested in the science of other sports? Email us at shortwave@npr.org — we'd love to hear from you.Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy

Tiny, black-capped chickadees have big memories. They stash food in hundreds to thousands of locations in the wild – and then come back to these stashes when other food sources are low. Now, researchers at Columbia University's Zuckerman Institute think neural activity that works like a barcode may be to thank for this impressive feat — and that it might be a clue for how memories work across species. Curious about other animal behavior mysteries? Email us at shortwave@npr.org.Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy

On April 8, the moon will slip in front of the sun, blocking its light and creating an eerie twilight in the middle of the day. Stars will come out, the air will get cold, colors will dance around the horizon. It's a full-body experience born from the total solar eclipse that will be visible from North America. Today on the show, Regina G. Barber talks to NPR science correspondent Nell Greenfieldboyce about why some people say this experience is one of the most beautiful celestial events you can see – and how to prepare for it. Want more ways to enjoy the eclipse? Check out Regina's interview with an eclipse chaser on NPR's Life Kit podcast. Share your eclipse stories with us at shortwave@npr.org! We'd love to see it!Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy

For Guyana the potential wealth from oil development was irresistible — even as the country faces rising seas. Today on the show, host Emily Kwong talks to reporter Camila Domonoske about her 2021 trip to Guyana and how the country is grappling with its role as a victim of climate change while it moves forward with drilling more oil. (encore)For more of Camila's reporting and pictures from her visit, check out "Guyana is a poor country that was a green champion. Then Exxon discovered oil."Want to more about how countries around the world are grappling with climate change? Write us at shortwave@npr.org to let us know — your suggestion might become a future episode! Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy

Historic numbers of animals across the globe have become endangered or pushed to extinction. But some of these species sit in limbo — not definitively extinct yet missing from the scientific record. Rediscovering a "lost" species is not easy. It can require trips to remote areas and canvassing a large area in search of only a handful of animals. But new technology and stronger partnerships with local communities have helped these hidden, "uncharismatic" creatures come to light. Have other scientific gray areas you want us to cover in a future episode? Email us at shortwave@npr.org!Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy

admin.html">According to the CDC, about one in four adults has a fear of needles. Many of those people say the phobia started when they were kids. For some people, the fear of needles is strong enough that they avoid getting important treatments, vaccines or tests. That poses a serious problem for public health. Researchers have helped develop a five step plan to help prevent what they call "needless pain" for kids getting injections or their blood drawn. Guest host Tom Dreisbach talks with Dr. Stefan Friedrichsdorf of UCSF Benioff Children's Hospitals, who works with a team to implement the plan at his own hospital. Friedrichsdorf told us some of the most important research on eliminating pain has come from researchers in Canada. Learn more about their work here. This episode was inspired by the reporting of our colleague April Dembosky, a journalist at member station KQED and KFF Health News. Read her digital story here.Got another question for a doctor? Email us at shortwave@npr.org.Learn more about sponsor message choices: podcastchoices.com/adchoicesNPR Privacy Policy