Could a new class of ocean worlds hold the key to finding life?
Astronomers are looking beyond Earth-sized planets to a new category of habitable candidates: Hycean worlds. This talk explores how the massive exoplanet K2-18b might host liquid oceans beneath a hydrogen-rich atmosphere.
In this presentation at the Royal Institution, Cambridge astrophysicist Nikku Madhusudhan examines the potential habitability of K2-18b, a planet 124 light-years away. While much larger than Earth—boasting 8.6 times its mass and 2.6 times its radius—this 'mini-Neptune' candidate could represent a new class of 'Hycean' worlds: temperate, ocean-covered planets with hydrogen-rich atmospheres.
Using data from the James Webb Space Telescope, researchers have identified carbon-bearing molecules and water vapour in K2-18b's atmosphere. The research focuses on whether its hydrogen envelope is thin enough to allow for liquid water at life-supporting temperatures and pressures. While detections of methane and ammonia levels provide clues, the team notes that determining if these chemical signatures stem from biological processes remains an ongoing mystery.
Source: The unexpected planet that could redefine the search for life in space | with Nikku Madhusudhan
