Scientists have re-examined data from the James Webb Space Telescope that previously suggested signs of life on exoplanet K2-18b. The University of Chicago researchers found that the evidence pointing to biological molecules, specifically dimethyl sulfide, may be far less solid than initially reported.
The study analyzed not only JWST data but also observations from other instruments and found overlapping signals with more common, non-biological molecules. “We have too much noise in the data to make a definitive conclusion,” said lead author Rafael Luque. The researchers concluded that there’s not enough certainty to say one way or the other about alien life.
Spectral analysis also raises concerns. Many compounds share similar spectral features, making it hard to distinguish between different molecules. Ethane, already detected on planets like Neptune and Uranus, is a plausible alternative candidate for the spectral signal attributed to dimethyl sulfide. The study’s authors urge caution in interpreting faint atmospheric signatures at interstellar distances.
The case of K2-18b highlights both the potential and limitations of current technology. While tools like JWST are groundbreaking, they are not immune to ambiguity and interference when analyzing distant objects. The search for biosignatures is crucial, but premature announcements can set back public trust and scientific credibility.
Source: https://dailygalaxy.com/2025/05/scientists-challenge-claim-life-k2-18b