Where Water Boils the Sky: Steam Worlds and the Search for Life

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.)