Scientists skeptical about recent claims that signs of life were possibly detected on exoplanet

Nicole Mortillaro · CBC News

· Posted: Apr 29, 2025 4:00 AM EDT | Last Updated: 3 hours ago

The hunt for beingness beyond our ain satellite is thing that astronomers person been doing for decades now, with nary results.

But connected April 17, a survey was published revealing that a squad of astronomers utilizing the James Webb Space Telescope (JWST), led by Nikku Madhusudhan, had discovered gases connected an exoplanet called K2-18b that could lone beryllium produced by life.

Right disconnected the bat, galore astronomers were a small skeptical astir the claim, saying determination wasn't robust grounds to enactment the findings.

"Discoveries similar this ... usually takes a agelong clip to confirm, and galore times it turned retired not true," Yanqin Wu told CBC News connected the time it was announced. "That's conscionable the disappointment successful existent technological endeavour. Extraordinary claims usually takes a batch of impervious and usually are wrong."

Now, a caller autarkic investigation of the JWST information has recovered nary grounds of biosignatures, signs that the planet's gases whitethorn person a biologic origin. 

Madhusudhan and his colleagues utilized information collected from JWST of the satellite passing successful beforehand of its big star, K2-18, and the antithetic molecules that were observed successful the spectra. This method is utile for determining which chemicals are successful the aerial of a planet.

The survey recovered the beingness of 2 gases — dimethyl sulfide, oregon DMS, and dimethyl disulfide, oregon DMDS — which are typically produced connected Earth by algae.

But Jake Taylor, a planetary idiosyncratic who besides studies exoplanets utilizing JWST data, utilized that information and examined it utilizing a antithetic method than the Madhusudhan-led survey and was incapable to replicate the findings. He published his results connected the pre-print tract ArXiv.

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In his method, helium utilized an "agnostic" approach, meaning helium didn't look for immoderate sulfur gases that could beryllium signs of beingness similar determination are present connected Earth. The effect was a "flat line" alternatively than immoderate wiggles successful the data, meaning that the dips recovered successful the archetypal survey were statistical sound — random accusation that tin effect survey results.

Taylor said helium was excited astir the survey and thought it was bully successful immoderate ways, but "when it came to the atmospheric physics side, I noticed that they didn't springiness excessively overmuch item astir their flat-line rejection tests."

He explained these tests are "kind of a modular wrong the field" to bash archetypal successful bid to guarantee determination isn't sound successful the data.

He said helium did talk with Madhusudhan personally astir this past week, who reassured him that the rejection tests had been conducted, though they weren't contained successful the survey itself.

Though helium said the existent information from JWST didn't supply capable assurance successful a biosignature detection, it doesn't mean it couldn't hap with further data.

"It's a bully archetypal measurement successful in this benignant of endeavour, due to the fact that this is simply a spectral scope we've ne'er seen before. So conscionable that successful itself is beauteous cool," Taylor said. "We decidedly would request much observations to get a amended signal. And who knows, it mightiness popular out, it mightiness beryllium there. It's conscionable close now, the signal-to-noise ratio is not definitive."

Asked if determination needs to beryllium much rigorous examinations of specified claims, Taylor said, "I deliberation determination needs to beryllium much discussions astir this. I bash personally deliberation that determination needs to beryllium aggregate lines of evidence, and besides determination needs to be like a exemplary autarkic confirmation that we spot something."

Taylor admitted he was a large instrumentality of The X-Files, a sci-fi amusement that mostly focused connected uncovering impervious of alien beingness connected Earth. Its astir touted catchphrase was "I privation to believe."

He also noted that planetary scientists looking for signs of beingness connected exoplanets do truly privation to 1 time find that robust motion of life, though it's not similar we could ever sojourn the exoplanet to corroborate with certainty.

"We privation to believe," helium said. "But we privation to bash it correctly."