The planet K2-18b has been hitting the headlines again this month with the claim of a tentative detection of something known as dimethyl sulphide (DMS) in its atmosphere from this paper by Madhusudhan et al. (2025)
DMS is a molecule that is only produced by microbial life here on Earth, but NO we have not detected alien life in this planetâs atmosphere. The detection itself of DMS is tentative, and the molecule itself, doesnât necessarily mean life. This whole story is quite literally the definition of âextraordinary claims require extraordinary evidenceâ.
Now if youâre thinking, wait havenât I heard this before? Technically, yes, the same research group put out this paper in 2023 claiming an even more tentative detection of DMS, but the data they had from the James Webb Space Telescope, JWST, using NIRSpec wasnât good enough to make a strong claim.
So now theyâve got different data from MIRI on JWST, and now theyâre claiming they have stronger evidence for DMS. But if youâve been following me for a while you know that all of this hype around K2-18b has come with a lot of scientific debate with other research papers claiming thereâs no evidence for DMS at all.
And this past week or so since this research dropped has been no different, with this paper from Taylor (2025) also fitting to the new JWST MIRI data and claiming thereâs no evidence for DMS at all. This is science in action and it is incredibly exciting to get to live through all of this debate! So letâs have a deep dive into thisâŠ