K2-18b has become one of the most discussed worlds in recent exoplanet research. The planet lies 124 light-years away in the constellation Leo, inside the habitable zone of its red dwarf star.
Observations from the James Webb Space Telescope indicate that its atmosphere contains abundant carbon dioxide and methane. That combination has made it a leading candidate for a “Hycean” world, meaning a planet with a thick hydrogen-rich atmosphere above a global ocean of liquid water.
Because K2-18b is such an appealing target for Search for Extraterrestrial Intelligence (SETI) researchers, scientists used two of the world’s most powerful radio telescopes to monitor its star system. A recent preprint on arXiv reports that, despite millions of possible detections, the team found no likely artificial narrowband radio signals from the planet at a level comparable to current human technology.
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