Key Points
- New data from the JWST show no evidence of life on the exoplanet K2-18 b.
- Initial reports had suggested the presence of molecules that are only produced by life on Earth.
- The new observations confirm that the planet is “water-rich.” Scientists are now trying to determine if the water exists as a gas, ice, or a liquid ocean.
- Despite showing no signs of life, K2-18b remains a prime target for studying potentially habitable environments.
A distant, sub-Neptune-sized planet that was once thought to show possible signs of life does not appear to host living organisms after all, according to new data from the James Webb Space Telescope (JWST). However, the new observations confirm that the planet is “water-rich,” making it a fascinating target for future study.
The planet, known as K2-18 b, is located 124 light-years away. Last year, some scientists reported detecting molecules in its atmosphere that, on Earth, are only produced by living things. This sparked a debate, as other research groups were unable to confirm the finding.
Now, a new study combining data from several JWST observations has settled the debate. The latest results show no evidence of the life-indicating molecules. But what they did find is a robust detection of methane and carbon dioxide in the planet’s hydrogen-rich atmosphere.
The researchers say the specific mix of these gases can only be explained if the planet has a significant amount of water in its interior. While they could not detect water vapor in the atmosphere, they believe it could be trapped at lower altitudes.
The big question now is what form that water takes. It could be a layer of gas, part of an icy core, or even a planet-wide ocean of liquid water. While the new data doesn’t confirm the existence of an ocean, the possibility keeps K2-18b at the top of the list for scientists studying potentially habitable worlds.
