On Earth, DMS is only produced by life, primarily microbial life such as marine phytoplankton, suggesting the possibility of biological activity on K2-18 b

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Researchers also identified another, weaker, signal in the K2-18 b spectrum. After several analyses, the researchers say that the signal could be caused by a molecule called dimethyl sulphide (DMS). On Earth, DMS is only produced by life, primarily microbial life such as marine phytoplankton, suggesting the possibility of biological activity on K2-18 b. While these signs of DMS are tentative and require further validation, the researchers say that K2-18 b and other Hycean planets could be our best chance to find life outside our Solar System.

The Webb telescope has identified the presence of carbon dioxide and methane within the atmosphere of exoplanet K2-18 b, which is considerably larger than Earth and considered a potentially habitable world. The data from Webb indicates the possibility that this planet could be predominantly covered by oceans and surrounded by a hydrogen-rich atmosphere.