SETI Live

Get ready for a fascinating deep dive into one of the biggest questions in astrobiology: How common are biological extraterrestrial intelligences in the Milky Way? Host Simon Steel, Deputy Director of the Carl Sagan Center for Research, is joined by Manuel Scherf and Helmut Lammer (Space Research Institute, Austrian Academy of Sciences) to explore new research that challenges long-held assumptions about "Earth-like" planets and what it really takes for a world to support complex life. Recent work from Scherf, Lammer, and colleagues revisits the idea of Eta-Earth — the number of truly Earth-like habitats in the Galaxy. Their models extend far beyond the basic "habitable zone" and incorporate a suite of filters, including stable atmospheres, oxygen-rich conditions, plate tectonics, subaerial land, and long-term planetary evolution. These filters significantly reduce the number of planets that could potentially host complex or technological life. The study finds that even under generous assumptions, the Milky Way may host at most 60,000 to 250,000 Earth-like habitats — and the number that actually evolve intelligent life could be far smaller. The result? A serious rethink of how rare (or precious) intelligent life might be. Join us as we explore what this means for SETI strategies, exoplanet surveys, and our own cosmic significance. It's a conversation that blends astrophysics, planetary science, and a bit of existential wonder — perfect for anyone curious about where life fits into the grand structure of the cosmos. Paper: https://www.liebertpub.com/doi/10.1089/ast.2023.0076  Conference Abstract: https://meetingorganizer.copernicus.org/EPSC-DPS2025/EPSC-DPS2025-1512.html (Recorded live 8 December 2025.)

In a special bonus SETI Live, communication specialist Beth Johnson welcomes astronomer and entrepreneur Franck Marchis to introduce SkyMapper, a new global network of smart telescopes and all-sky sensors designed to open the universe to everyone. SkyMapper brings together professional observatories, citizen astronomers, and classrooms into a single, decentralized platform. It enables real scientific discovery — from tracking satellites and meteors to monitoring comets and transient events in real time — while giving students and the public the chance to observe the sky, contribute data, and learn how modern astronomy works. We'll talk about the science, the outreach mission, the importance of the SETI Institute's partnership with SkyMapper, and why a worldwide, always-on view of the sky matters more than ever for research, education, and our shared curiosity. Join us live and discover how you can be part of this new way of exploring the universe. 📚 Learn more about SkyMapper: www.skymapper.io  👋 Join the SkyMapper community on Telegram: https://t.me/skymapper_community  ✅ Follow SkyMapper on social media: BlueSky: @skymapper.bsky.social X (formerly Twitter): @Skymapperspace LinkedIn: https://www.linkedin.com/company/skymapper-inc/  Reddit: https://www.reddit.com/r/SkyMapper/ (Recorded live 5 December 2025.)

On this episode of SETI Live, host Moiya McTier welcomes two leading researchers—Gabriele Cugno (University of Zürich) & Sierra L. Grant (Carnegie Institution for Science)—to dive into an extraordinary discovery by the James Webb Space Telescope (JWST): a carbon-rich, moon-forming disk around the distant exoplanetary object CT Cha b, some 625 light-years away. What exactly is a "moon-forming disk"? Why is this discovery a game-changer for our understanding of how moons — and ultimately habitable environments around them — can form? Gabriele and Sierra walk us through spectroscopy, chemistry (including acetylene, benzene, and more), observational challenges, and the big philosophical questions: Could moons be even more common than planets? What does this tell us about our own Solar System's past — and the possibilities for life elsewhere? 📚 For more: NASA Press Release: https://science.nasa.gov/science-research/nasas-webb-telescope-studies-moon-forming-disk-around-massive-planet/  Research Paper: https://iopscience.iop.org/article/10.3847/2041-8213/ae0290 (Recorded live 4 December 2025.)

Join host Beth Johnson for a fascinating episode of SETI Live, featuring planetary scientists Dr Georgina Miles and Dr Carly Howett from the University of Oxford. We'll be unpacking their groundbreaking study showing that Enceladus — one of Saturn's icy moons — may harbor a stable subsurface ocean capable of supporting life. 📄 For more info: The study "Endogenic heat at Enceladus' north pole" has just been published in Science Advances: https://www.science.org/doi/10.1126/sciadv.adx4338  Official press release from the University of Oxford: https://www.ox.ac.uk/news/2025-11-10-saturn-s-icy-moon-may-host-stable-ocean-fit-life-new-study-finds (Recorded live 20 November 2025.)

What happens when a planet is full of water—but too hot for oceans? Meet the "steam worlds," exotic exoplanets wrapped in thick water vapor and boiling at thousands of degrees. These strange worlds may be far from habitable, but they're reshaping how scientists think about planets, water, and where life might exist. In this episode of SETI Live, host Beth Johnson talks with Artem Aguichine of the University of California, Santa Cruz, about his new research modeling the interiors and atmospheres of steam worlds—a class of water-rich sub-Neptunes that could dominate our galaxy. With data from the JWST revealing steam signatures on distant planets, these models are helping scientists decode what's really going on beneath the haze. Join us as we explore: • What defines a "steam world" and how it forms • How water behaves under crushing pressure and searing heat • Why JWST's new observations are changing the game • What these discoveries mean for the future search for life beyond Earth 🔗 Learn more: UCSC Press Release – https://news.ucsc.edu/2025/08/new-model-steam-worlds  Research Paper – https://iopscience.iop.org/article/10.3847/1538-4357/add935 (Recorded live 13 November 2025.)