Exoplanet Atmospheres

JWST detected carbon dioxide and water vapor on exoplanet K2-18b, 120 light-years distant. This "Hycean" world—hydrogen-rich ocean planet—represents a new habitable category. While surface conditions remain unknown, the finding proves we can analyze distant atmospheres for biosignatures. Within decades, telescopes may detect oxygen and methane combinations suggesting life. The search isn't for Little Green Men; it's for microbial metabolism transforming planetary chemistry across the galaxy.