A new investigation with NASA’s James Webb Space Telescope into K2-18 b, an exoplanet 8.6 times as massive as Earth, has revealed the presence of carbon-bearing molecules including methane and carbon dioxide. Webb’s discovery adds to recent studies suggesting that K2-18 b could be a Hycean exoplanet, one which has the potential to possess a hydrogen-rich atmosphere and a water ocean-covered surface.

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The abundance of methane and carbon dioxide, and shortage of ammonia, support the hypothesis that there may be a water ocean underneath a hydrogen-rich atmosphere in K2-18 b. These initial Webb observations also provided a possible detection of a molecule called dimethyl sulfide (DMS). On Earth, this is only produced by life. The bulk of the DMS in Earth’s atmosphere is emitted from phytoplankton in marine environments.

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The inference of DMS is less robust and requires further validation. “Upcoming Webb observations should be able to confirm if DMS is indeed present in the atmosphere of K2-18 b at significant levels,” explained Madhusudhan.

While K2-18 b lies in the habitable zone, and is now known to harbor carbon-bearing molecules, this does not necessarily mean that the planet can support life. The planet's large size — with a radius 2.6 times the radius of Earth — means that the planet’s interior likely contains a large mantle of high-pressure ice, like Neptune, but with a thinner hydrogen-rich atmosphere and an ocean surface. Hycean worlds are predicted to have oceans of water. However, it is also possible that the ocean is too hot to be habitable or be liquid.

Tantalising sign of possible life on faraway world

Nasa's James Webb Space Telescope may have discovered tentative evidence of a sign of life on a faraway planet.

It may have detected a molecule called dimethyl sulphide (DMS). On Earth, at least, this is only produced by life.

The researchers stress that the detection on the planet 120 light years away is "not robust" and more data is needed to confirm its presence.

Researchers have also detected methane and CO2 in the planet's atmosphere.

Detection of these gases could mean the planet, named K2-18b, has a water ocean.

Prof Nikku Madhusudhan, of the University of Cambridge, who led the research, told BBC News that his entire team were ''shocked'' when they saw the results.

"On Earth, DMS is only produced by life. The bulk of it in Earth's atmosphere is emitted from phytoplankton in marine environments," he said.

B.B.C.

Spearthrower wrote:Yup, and frankly, an alien world may have inorganically produced chemical reactions we can't yet imagine even if there's no biotic element.