Astronomers using the James Webb Space Telescope say they have stumbled onto possible signs of life coming from a massive Earth-like exoplanet, NASA confirmed in a release.
K2-18 b is an exoplanet — a planet outside our solar system — that’s 8.6 times as massive as Earth. A new investigation with the JWST revealed the presence of “carbon-bearing molecules” that include methane and carbon dioxide. The findings add to recent studies that suggest that K2-18 b could be a Hycean exoplanet, meaning it has the potential to hold a hydrogen-rich atmosphere and a water-covered surface, NASA reported.
Astronomers first studied K2-18 b’s atmosphere with NASA’s Hubble Space Telescope in 2019. The results prompted further studies of the massive exoplanet that have changed experts understanding of the system.
“Our findings underscore the importance of considering diverse habitable environments in the search for life elsewhere,” explained Nikku Madhusudhan, an astronomer at the University of Cambridge and lead author of the paper announcing these results.
What is K2-18 b?
K2-18 b is an exoplanet that lies 120 light-years from us in the constellation Leo and orbits in the habitable zone of a cooler dwarf star, K2-18.
It is classified as “Mini-Neptune” due to its size, which experts said is unlike anything in our solar system, making it hard to understand, with the atmospheres of these planets actively debated among astronomers.
An abundance of methane and carbon dioxide and a shortage of ammonia support the idea that there might be a water ocean hiding below the hydrogen-rich atmosphere of K2-18 b, NASA said.
These JWST observations showed a possible detection of a molecule called dimethyl sulfide (DMS). On Earth, this is only produced by life. Most of the DMS in Earth’s atmosphere is emitted from phytoplankton in marine environments, according to NASA.
“These results are the product of just two observations of K2-18 b, with many more on the way,” explained team member Savvas Constantinou of the University of Cambridge. “This means our work here is but an early demonstration of what Webb can observe in habitable-zone exoplanets.”