Astronomers searching for alien life aimed the James Webb Space Telescope at K2-18 b, a potentially ocean-bearing world 124 light-years away, and found tentative signs of gases associated on Earth wit
Astronomers using the James Webb Space Telescope have identified tentative spectral signatures of dimethyl sulphide on the exoplanet K2-18 b. While these gases are associated with marine life on Earth, researchers emphasize that this is not a confirmed detection of alien life and requires further study.
Why it matters
The potential discovery of biosignatures on a distant 'Hycean' world represents a significant milestone in the search for life beyond our solar system.
A faint spectral signature hinting at gases tied to Earth's ocean life has scientists arguing whether we're seeing biosignatures or just chemistry.
By Space Daily Editorial Team · Editorial process
K2-18 b became the most argued-over exoplanet of 2025 because a faint pattern in James Webb Space Telescope data appeared compatible with dimethyl sulphide, or DMS, and dimethyl disulphide, or DMDS. On Earth, DMS in the atmosphere is closely tied to marine microbial activity. The observation was interesting. It was not a detection of life.
K2-18 b lies about 124 light-years away and is much larger than Earth. It has been proposed as a “Hycean” world, with a deep ocean beneath a hydrogen-rich atmosphere, but that interior remains hypothetical. What Webb directly measures is the small change in starlight as the planet passes in front of its red-dwarf star.
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