NASA: Possible Signs of Life Found on Exoplanet

The James Webb Space Telescope detected evidence of a planet 120 light years from Earth that could potentially support water and life, NASA said in a press release.

A new investigation with the telescope revealed the presence of "carbon-bearing molecules" on K2-18 b, including methane and carbon dioxide. The exoplanet, or planet outside our solar system, is 8.6 times as big as Earth and orbits in the habitable zone of the cool dwarf star K2-18.

The discovery adds to recent studies suggesting that K2-18 b could be a Hycean exoplanet, which means it has the potential to possess a hydrogen-rich atmosphere and a water-covered surface, NASA said.

Some astronomers believe that Hycean exoplanets are "promising environments to search for evidence of life."

"Our findings underscore the importance of considering diverse habitable environments in the search for life elsewhere," said Nikku Madhusudhan, an astronomer at the University of Cambridge and lead author of the paper announcing the results. "Traditionally, the search for life on exoplanets has focused primarily on smaller rocky planets, but the larger Hycean worlds are significantly more conducive to atmospheric observations."

NASA's Hubble Space Telescope provided the first insight into the atmospheric properties of K2-18 b in 2019 and further studies of the exoplanet have since changed experts' understanding of the system.

Exoplanets like K2-18 b, which range in size from Earth to Neptune, are "unlike anything in our solar system," making them "poorly understood," NASA said. The nature of the atmospheres of these planets is debated among astronomers.

The abundance of methane and carbon dioxide, and shortage of ammonia, supports the idea that there may be a water ocean underneath the hydrogen-rich atmosphere of K2-18 b.

The telescope's observations also possibly detected a molecule called dimethyl sulfide (DMS). On Earth, this molecule is only produced by life. The majority of the DMS in Earth's atmosphere is emitted from phytoplankton in marine environments, according to NASA.

"Upcoming Webb observations should be able to confirm if DMS is, indeed, present in the atmosphere of K2-18 b at significant levels," Madhusudhan said.

Astronomers plan more research using the telescope's MIRI (Mid-Infrared Instrument) spectrograph that they hope will validate their findings and provide new insight into K2-18 b's environment.

"Our ultimate goal is the identification of life on a habitable exoplanet, which would transform our understanding of our place in the universe," Madhusudhan said. "Our findings are a promising step towards a deeper understanding of Hycean worlds in this quest."

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