DMS Hints at Life on K2‑18b

Updated: 2025.09.10 1M ago 3 sources
JWST transmission spectra reportedly show dimethyl sulfide (and dimethyl disulfide) at ~10 ppm in the hydrogen‑rich atmosphere of K2‑18b, with ~3σ significance. On Earth, DMS is primarily biogenic, and the article outlines a plausible Hycean biosphere (H2‑based photosynthesis, methanogenesis, nutrient cycling through ice‑VII breaks) that could generate it. — A potential exoplanet biosignature shifts the life‑is‑rare priors and reframes SETI, origins‑of‑life research, and the Great Filter debate.

Sources

NASA Says Mars Rover Discovered Potential Biosignature Last Year
msmash 2025.09.10 55% relevant
Both pieces center on biosignature claims that are suggestive but not conclusive, emphasizing cautious interpretation and the need for follow‑up evidence—here via in‑situ Mars geology (Perseverance’s 'Sapphire Canyon' sample) rather than exoplanet atmospheric spectra.
JWST could expose alien biosignatures on hazy exoplanets
Ethan Siegel 2025.09.10 50% relevant
Both pieces address JWST-era biosignature detection in hazy, non‑Earthlike exoplanet atmospheres; this article extends the theme by outlining a lab‑model‑observation framework (led by Dr. Chao He) for interpreting hazes and mixed gases, which would directly inform how to evaluate claimed DMS-like biosignatures on Hycean/sub‑Neptune worlds.
And Then There Were Two?
John Carter 2025.04.18 100% relevant
The claim of JWST detection of DMS/DMDS on K2‑18b at ~3σ and ~10 ppmv, contrasted with Earth and modeled spectra.
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