Scientists see signs of a molecule that points to life on an exoplanet

Astronomers from the University of Cambridge in the United Kingdom have discovered possible signs of dimethyl sulfide (DMS) on a planet eight times larger than Earth and located outside Earth. Solar system (exoplanet). This molecule is a sign of biological activity, i.e. life.

While this is ultimately encouraging news, it does answer the question, “Are we alone?” At the heart of exoplanet research, the signal is “weak” and, according to the researchers involved, more observations are needed to understand “potential atmospheric and internal processes involved.” The results were published in the scientific journal The Astrophysical Journal Letters and used data from The Astrophysical Journal Letters James Webb Space Telescope.

“Our ultimate goal is to identify life on a habitable exoplanet, which would change our understanding of our place in the universe,” said Nico Madhusudan, an astronomer and lead author of the study. “Our findings are a promising first step in this direction.” Cambridge University News Office portal.

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According to researchers, DMS on Earth is a “by-product” of living organisms. It is emitted by phytoplankton in marine environments. Although they stress that discovering the molecule requires a more comprehensive investigation, they are keen for more observations from NASA’s telescope. For this material, only two were used. “Our findings demonstrate the feasibility of detecting a biosignal molecule in the atmosphere of a sub-Neptune (exoplanet) in the habitable zone with James Webb,” they highlight in the article.

NASA explains that in order for scientists to be able to read the atmosphere of these exoplanets, the telescope captures light from the stars. Gases in the atmosphere block certain parts of the spectrum of this light. In other words, it’s almost like reading a barcode.

The exoplanet K2-18 b, which may contain the molecule, orbits the dwarf star K2-18 in the habitable zone, 110 light-years away from Earth, in the constellation Leo, and has a mass 8.6 times the mass of our planet. His first observations were made with the Hubble Space Telescope.

Researchers had already proposed classifying it as a Hessian planet (a planet that likely has a hydrogen-rich atmosphere and an oceanic surface covered in water). For scientists, these are the most promising worlds in the search for evidence of life.

The abundance of methane and carbon dioxide and scarcity of ammonia that scientists capture supports the hypothesis that there may be an ocean of water beneath a hydrogen-rich atmosphere on this distant planet. In contrast to the DMS signature, these other molecules appeared more clearly in the analysis.

But according to NASA, the planet’s size means its interior “most likely contains a large, high-pressure ice layer,” like Neptune. “The ocean is likely too hot to be habitable or liquid.”

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