Probing Where the Sun Does Shine: A Holiday Special

When neuroscientist Madeline Lancaster was a brand new postdoc, she accidentally used an expired protein gel in a lab experiment and noticed something weird. The stem cells she was trying to grow in a dish were self-assembling. The result? Madeline was the first person ever to grow what she called a “cerebral organoid,” a tiny, 3D version of a human brain the size of a peppercorn. In about a decade, these mini human brain balls were everywhere. They were revealing bombshell secrets about how our brains develop in the womb, helping treat advanced cancer patients, being implanted into animals, even playing the video game Pong. But what are they? Are these brain balls capable of sensing, feeling, learning, being? Are they tiny, trapped humans? And if they were, how would we know? Special thanks to Lynn Levy, Jason Yamada-Hanff, David Fajgenbaum, Andrew Verstein, Anne Hamilton, Christopher Mason, Madeline Mason-Mariarty, the team at the Boston Museum of Science, and Howard Fine, Stefano Cirigliano, and the team at Weill-Cornell. EPISODE CREDITS: Reported by - Latif Nasserwith help from - Mona MadgavkarProduced by - Annie McEwen, Mona Madgavkar, and Pat Walterswith mixing help from - Jeremy BloomFact-checking by - Natalie Middleton and Rebecca Randand Edited by  - Alex Neason and Pat Walters EPISODE CITATIONS: Videos - “Growing Mini Brains to Discover What Makes Us Human,” Madeline Lancaster’s TEDxCERN Talk, Nov 2015 (https://zpr.io/6WP7xfA27auR) Brain cells playing Pong (https://zpr.io/pqgSqguJeAPK) Reuters report on CL1 computer launch in March 2025 (https://zpr.io/cdMf8Yjvayyd) Articles - Madeline Lancaster: The accidental organoid – mini-brains as models for human brain development (https://zpr.io/nnwFwUwnm2p6), MRC Laboratory of Molecular Biology What We Can Learn From Brain Organoids (https://zpr.io/frUfsg4pxKsb), by Carl Zimmer. NYT, November 6, 2025 Ethical Issues Related to Brain Organoid Research (https://zpr.io/qyiATHEhdnSa), by Insoo Hyun et al, Brain Research, 2020 Brain organoids get cancer, too, opening a new frontier in personalized medicine (https://zpr.io/nqMCQ) STAT Profile of Howard Fine and his lab’s glioblastoma research at Weill Cornell Medical Center: By re-creating neural pathway in dish, Stanford Medicine research may speed pain treatment (https://zpr.io/UnegZeQZfqn2) Stanford Medicine profile of Sergiu Pasca’s research on pain in organoids A brief history of organoids (https://zpr.io/waSbUCSrL9va) by Corrò et al, American Journal of Physiology - Cell Physiology, Books - Carl Zimmer Life’s Edge: The Search for What it Means to be Alive (https://carlzimmer.com/books/lifes-edge/) Sign up for our newsletter!! It includes short essays, recommendations, and details about other ways to interact with the show. Signup (https://radiolab.org/newsletter)! Radiolab is supported by listeners like you. Support Radiolab by becoming a member of The Lab (https://members.radiolab.org/) today. Follow our show on Instagram, Twitter and Facebook @radiolab, and share your thoughts with us by emailing [email protected] support for Radiolab’s science programming is provided by the Simons Foundation and the John Templeton Foundation. Foundational support for Radiolab was provided by the Alfred P. Sloan Foundation.

In 1971, a red-headed, tree-loving astronaut named Stu ‘Smokey’ Roosa was asked to take something to the moon with him. Of all things, he chose to take a canister of 500 tree seeds. After orbiting the moon 34 times, the seeds made it back to Earth. NASA decided to plant the seeds all across the country and then… everyone forgot about them. Until one day, a third grader from Indiana stumbled on a tree with a strange plaque: "Moon Tree." This discovery set off a cascading search for all the trees that visited the moon across the United States. Science writer, and our very own factchecker, Natalie Middleton (https://www.nataliemiddleton.org/) tells us the tale. Read Lulu’s remembrance of Alice Wong for Transom.org: 13 questions I’ll never get to ask Alice Wong (https://transom.org/2026/13-questions-ill-never-get-to-ask-alice-wong/). Check out Natalie’s map to find your nearest moon tree on our show page (https://radiolab.org/podcast/the-travelers-how-moon-trees-hide-among-us)! Help us hunt for more moon trees. If you know of an undocumented moon tree, contact Natalie at nataliemiddleton.org. Check out Natalie’s essay on Moon Trees (https://orionmagazine.org/article/moon-tree/) and Space Zinnias (https://orionmagazine.org/article/astronaut-scott-kelly-flower-experiment-space/) in Orion Magazine (https://orionmagazine.org/). Visit NASA’s official Moon Tree Page (https://science.nasa.gov/resource/apollo-moon-trees/) for a list of all the Apollo 14 Moon Trees in the world. To learn more about Stu Roosa or to learn more about acquiring your own half Moon Tree, check out the Moon Tree Foundation (https://www.moontreefoundation.com/), spearheaded by Stu’s daughter, Rosemary Roosa. A reminder that Terrestrials also makes original music! You can find ‘Tangled in the Roots’ and all other music from the show here (https://www.wnycstudios.org/podcasts/radiolab-kids/just-the-songs). EPISODE CREDITS: Terrestrials was created by Lulu Miller with WNYC Studios. This episode was produced by Tanya Chawla and sound-designed by Joe Plourde. Our Executive Producer is Sarah Sandbach. Our team includes Alan Goffinski, Ana González and Mira Burt-Wintonick. Fact checking was by Diane Kelly. Special thanks to Sumanth Prabhaker from Orion magazine, retired NASA Scientist Dr. Dave Williams, Joan Goble, Tre Corely and NASA scientist Dr. Marie Henderson. Our advisors for this show were Ana Luz Porzecanski, Nicole Depalma, Liza Demby and Carly Ciarrocchi. Support for Terrestrials also comes from the Simons Foundation, the Arthur Vining Davis Foundations, and the John Templeton Foundation. Signup for our newsletter!! It includes short essays, recommendations, and details about other ways to interact with the show. Sign up (https://radiolab.org/newsletter)! Radiolab is supported by listeners like you. Support Radiolab by becoming a member of The Lab (https://members.radiolab.org/) today. Follow our show on Instagram, Twitter and Facebook @radiolab, and share your thoughts with us by emailing [email protected] support for Radiolab’s science programming is provided by the Simons Foundation and the John Templeton Foundation. Foundational support for Radiolab was provided by the Alfred P. Sloan Foundation.

After 35, does fertility tank? As she -- and her friends — approached the age of 35, senior correspondent Molly Webster kept hearing a phrase over and over: “fertility cliff.” It was a short-hand term to describe what she was told would happen to her fertility after she turned 35 — that is, it would drop off. Suddenly, sharply, dramatically. And this was well before she was supposed to hit menopause. Intrigued, Molly decided to look into it — what was the truth behind this so-called cliff, and when, if so, would she topple? This story first premiered in “Thirty Something,” a 2018 Radiolab live show that was part of, Gonads, (https://radiolab.org/series/radiolab-presents-gonads)a six-episode audio and live event series all about reproduction and the parts of us that make more of us. The live event was produced by Rachael Cusick and edited by Pat Walters. Special thanks to epidemiologist Lauren Wise, at Boston University. Plus, Emily, Chloe, and Bianca. And of course, Jad Abumrad. If you’re more of a visual person, here are the graphs we explain in the episode, we also include links to the corresponding papers in our Episode Citations Section, below! LINK TO GRAPHS: https://media.wnyc.org/i/1860/1046/c/80/2025/12/FERTILITY_AGE_GRAPHS_1-4.jpg EPISODE CREDITS: Reported by - Molly Webster Produced by - Arianne Wack Fact-checking by - Diane A. Kelly EPISODE CITATIONS: Audio: Gonads (https://radiolab.org/series/radiolab-presents-gonads/) A six-part audio series on reproduction and the parts of us that make more of us The Menopause Mystery (https://radiolab.org/podcast/the-menopause-mystery) One of Radiolab’s most listened-to episodes of 2025! Videos: “Radiolab Presents: Thirty Something” https://youtu.be/LOJVAaSwags?si=czCBraHf1JEqmAQi Research Articles: Graph 1: Can assisted reproduction technology compensate for the natural decline in fertility with age? A model assessment (https://zpr.io/ft6dqdbkJnTd) Graph 2: Ovarian aging: mechanisms and clinical consequences (https://zpr.io/GrPLebynpvxV) , Brookmans, et al. BUT, the graph was borrowed and actually comes from this 1991 paper, Delaying childbearing: effect of age on fecundity and outcome of pregnancy” (https://zpr.io/whWg2UAZsb6h) Graph 3 and 4: Age and fecundability in a North American preconception cohort study, (https://zpr.io/Rmqry4Kd67hY) Wise et al; Dutch fertility research Further reading: Predicting Fertility, (https://zpr.io/YEdfiYT29rUh): Magazine article on Lauren Wise’s research, Sign up for our newsletter!! It includes short essays, recommendations, and details about other ways to interact with the show. Signup (https://radiolab.org/newsletter)! Radiolab is supported by listeners like you. Support Radiolab by becoming a member of The Lab (https://members.radiolab.org/) today. Follow our show on Instagram, Twitter and Facebook @radiolab, and share your thoughts with us by emailing [email protected]. Leadership support for Radiolab’s science programming is provided by the Simons Foundation and the John Templeton Foundation. Foundational support for Radiolab was provided by the Alfred P. Sloan Foundation.

The standard view of evolution is that living things are shaped by cold-hearted competition. And there is no doubt that today's plants and animals carry the genetic legacy of ancestors who fought fiercely to survive and reproduce. But in this hour that we first broadcast back in 2010, we wonder whether there might also be a logic behind sharing, niceness, kindness ... or even, self-sacrifice. Is altruism an aberration, or just an elaborate guise for sneaky self-interest? Do we really live in a selfish, dog-eat-dog world? Or has evolution carved out a hidden code that rewards genuine cooperation? Sign up for our newsletter!! It includes short essays, recommendations, and details about other ways to interact with the show. Sign up (https://radiolab.org/newsletter)! Radiolab is supported by listeners like you. Support Radiolab by becoming a member of The Lab (https://members.radiolab.org/) today. Follow our show on Instagram, Twitter and Facebook @radiolab, and share your thoughts with us by emailing [email protected] support for Radiolab’s science programming is provided by the Simons Foundation and the John Templeton Foundation. Foundational support for Radiolab was provided by the Alfred P. Sloan Foundation.

It’s faster than a speeding bullet. It’s smarter than a polymath genius. It’s everywhere but it’s invisible. It’s artificial intelligence. But what actually is it? Today we ask this simple question and explore why it’s so damn hard to answer. Special thanks to Stephanie Yin and the New York Institute of Go for teaching us the game. Mark, Daria and Levon Hoover Brauner for helping bring NETtalk to life. And a huge thank you to Grant Sanderson for his unending patience explaining the math of neural nets to us. To learn more about how these 'thinking machines' actually think, we highly recommend his wonderful youtube channel 3Blue1Brown (https://www.youtube.com/watch?v=aircAruvnKk).EPISODE CREDITS: Reported by - Simon AdlerProduced by - Simon AdlerOriginal music from - Simon AdlerSound design contributed by - Simon AdlerFact-checking by - Anna Pujol-Mazzini Sign up for our newsletter!! It includes short essays, recommendations, and details about other ways to interact with the show. Signup (https://radiolab.org/newsletter)! Radiolab is supported by listeners like you. Support Radiolab by becoming a member of The Lab (https://members.radiolab.org/) today. Follow our show on Instagram, Twitter and Facebook @radiolab, and share your thoughts with us by emailing [email protected]. Leadership support for Radiolab’s science programming is provided by the Gordon and Betty.