How to search for alien planets - with Nikku Madhusudhan

Are we alone in the universe? An astrophysicist answers one of the oldest and most primal questions of humankind. This talk was filmed at the Royal Institution on the 27th of October 2025 --- Subscribe for regular science videos: http://bit.ly/RiSubscRibe Join this channel to get early access to lectures and other perks: https://www.youtube.com/channel/UCYeF244yNGuFefuFKqxIAXw/join --- But we may be closer to finding an answer, thanks to a recently-proposed new class of habitable exoplanets called Hycean worlds. Hycean planets are expected to be temperate ocean-covered worlds with H2-rich atmospheres, and thanks to their larger sizes and more extended atmospheres, compared to rocky planets of similar mass, Hycean worlds are significantly more accessible to atmospheric spectroscopy. The James Webb Space Telescope (JWST) recently observed the atmospheric spectrum of a possible Hycean world for the first time, named K2-18 b, which led to inferences of multiple carbon-bearing molecules in its atmosphere with hints of a potential biomarker. Astrophysicist and exoplanet expert Nikku Madhusudhan will present the observations from K2-18b, and what they’ve taught us about the atmospheric composition and physical processes, along with the possibility of a habitable ocean underneath the atmosphere. Discover the latest future prospects in the search for habitable environments, and life beyond the solar system in the next decade. --- The Ri is on Twitter: http://twitter.com/ri_science and Facebook: http://www.facebook.com/royalinstitution and TikTok: https://www.tiktok.com/@ri_science Listen to the Ri podcast: https://podcasters.spotify.com/pod/show/ri-science-podcast Donate to the RI and help us bring you more lectures: https://www.rigb.org/support-us/donate-ri Our editorial policy: https://www.rigb.org/editing-ri-talks-and-moderating-comments Subscribe for the latest science videos: http://bit.ly/RiNewsletter --- Nikku Madhusudhan is a Professor of Astrophysics and Exoplanetary Science at the Institute of Astronomy at the University of Cambridge. He is credited with pioneering atmospheric retrieval methods for determining the atmospheric properties of exoplanets using spectroscopic observations with large telescopes, besides other important developments in the understanding of the atmospheres, interiors, formation conditions, and habitability of exoplanets. --- Chapters: 00:00 Why Finding Alien Life Changes Everything 🌌 00:42 Meet the Astrophysicist Behind the Discovery 👨‍🔬 01:05 6,000 Exoplanets… But Which Ones Matter? 🪐 02:10 What Makes a Planet Habitable? (Habitable Zone Explained) 🌍 03:25 Why Distance Matters: Limits of Our Telescopes 🔭 04:05 Only 10 Planets We Can Study Right Now 🎯 04:32 How Scientists Detect Alien Atmospheres 🌫️ 05:05 What Are Biosignatures? Signs of Life Explained 🧬 05:40 Transmission Spectroscopy Made Simple 🌈 06:55 K2-18b: The Most Promising Planet for Life? 🪐 08:05 The Big Surprise: A “Non-Habitable” Planet Might Be Habitable 💡 09:10 Hycean Worlds: Ocean Planets with Hydrogen Atmospheres 🌊 10:05 JWST Discoveries: Methane, CO₂ & Missing Molecules 🔬 10:45 Dimethyl Sulfide (DMS): A Potential Biosignature 🧪 11:40 Are We Close to Detecting Alien Life? 🚨 12:05 What Could Life on K2-18b Actually Look Like? 🦠 12:40 The Big Unknown: Why We Must Be Careful ❓ Product links on this page may be affiliate links which means it won't cost you any extra but we may earn a small commission if you decide to purchase through the link. #alienlife #exoplanets #habitableplanets #searchforlife #astrobiology #jameswebbspacetelescope #k218b #biosignatures #alienbiosignatures #alienplanets #hyceanworlds #spacediscoveries #arewealone #newplanetdiscovery