“This is the strongest evidence yet there is possibly life out there. I can realistically say that we can confirm this signal within one to two years,” said Madhusudhan, as per BBC.
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What is K2-18b?
K2-18b is an exoplanet — a planet outside our solar system — that orbits the cool red dwarf star K2-18, located in the Leo constellation. The planet lies within the habitable zone of its star, a region where temperatures may allow liquid water to exist.
Around 2.6 times the size of Earth and 8.6 times its mass, K2-18b is considered a sub-Neptune — a category of planet not present in our solar system but believed to host hydrogen-rich atmospheres and possibly liquid water oceans beneath.
This makes it a strong candidate for a so-called Hycean world, a term coined for planets with hydrogen-dominated atmospheres and ocean-covered surfaces — conditions that could be favourable to life.
What the Webb Telescope found
Using JWST’s Near-Infrared Imager and Slitless Spectrograph (NIRISS) and Near-Infrared Spectrograph (NIRSpec), scientists detected the presence of methane and carbon dioxide, and the absence of ammonia. This chemical mix matches predictions for Hycean planets.
Also Read: | Scientists discover water vapour in distant Earth-like exoplanet K2-18b
Most notably, researchers observed a possible hint of dimethyl sulfide (DMS) — a molecule that, on Earth, is only produced by biological processes, primarily by marine phytoplankton. However, NASA cautions that this potential detection is not yet confirmed, and further observations are required.
“Upcoming Webb observations should be able to confirm if DMS is indeed present in the atmosphere of K2-18b at significant levels,” the agency stated.
Who is Dr. Nikku Madhusudhan?
He is a Professor of Astrophysics and Exoplanetary Science at the Institute of Astronomy, University of Cambridge. He completed his B. Tech at IIT-BHU and earned his MS and PhD in Physics from MIT.
Madhusudhan has held academic positions at Yale, Princeton, MIT, and Cambridge, and has received several honours such as the 2019 MERAC Prize in Theoretical Astrophysics from the European Astronomical Society and the 2016 Young Scientist Medal in Astrophysics from the International Union for Pure and Applied Physics.
His research integrates observations from major telescopes including the Hubble Space Telescope and the James Webb Space Telescope. His team’s work also expands the scope of habitable planet research, moving beyond Earth-like rocky planets to include oceans under thick hydrogen atmospheres.
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“If we confirm that there is life on k2-18b it should basically confirm that life is very common in the galaxy,” said Madhusudhan.
The team plans to conduct more detailed JWST observations in the coming year to confirm the presence of DMS and refine atmospheric models for K2-18b.
The European Space Agency’s upcoming Ariel mission, expected to launch in 2029, will also help scientists probe the atmospheres of exoplanets like K2-18b.
(With inputs from BBC and Daily Mail)
