K2-18 b orbits a cool red dwarf M-type star 124 light-years from Earth, measuring 2.4 × Earth in radius with a mass of 8.9 Earth masses. It completes its orbit every 32.9 days at 0.14 AU, comfortably within the habitable zone. Atmospheric studies reveal water vapor, methane, and possible biosignature hints. As a potential ocean world with a hydrogen envelope, it bridges rocky terrestrials and gaseous giants, inviting profound questions about diverse habitable environments. It endures in the Galactic Codex as a prime target for future telescopes seeking signs of life among the stars.
