NASA's Webb telescope looked at the sub-Neptune exoplanet K2-18 b. It found methane, carbon dioxide, a possible ocean, and even ... maybe ... a biosignature.
The post Did Webb find signs of life on exoplanet K2-18 b? first appeared on EarthSky.
Did the James Webb Space Telescope spot signs of life on a distant planet? On September 11, 2023, NASA announced that Webb made some exciting discoveries while observing an exoplanet called K2-18 b. They said the planet has methane and carbon dioxide in its atmosphere, which indicates it might be a Hycean world, one with a deep hydrogen atmosphere and global water ocean. But the extraordinary news is that Webb found hints of a molecule called dimethyl sulfide (DMS). On Earth, only life produces dimethyl sulfide, such as bacteria and phytoplankton in oceans. Does that mean Webb has found signs of life on exoplanet K2-18 b? Well, first, the finding of dimethyl sulfide needs to be confirmed. And then, scientists have to learn more about the exoplanet. While it is in the habitable zone of its star, its environment could still be unfavorable to life. As NASA said, it may have a hostile environment due to its active star, or its ocean may also be too hot to be habitable. Still, the new discovery is tantalizing. While studying the exoplanet K2-18 b, @NASAWebb hinted at a detection of dimethyl sulphide (DMS). On Earth, this molecule is only produced by microbial life. Because the detection needs to be confirmed, the team will follow up with additional observations. https://t.co/lYRNSVgI0M pic.twitter.com/Ui3c1fDbSf — NASA Exoplanets (@NASAExoplanets) September 11, 2023 More about K2-18 b K2-18 b is what scientists call a sub-Neptune or mini-Neptune. The exoplanet is 2.6 times larger and 8.6 times more massive than Earth. The new data from Webb show that the exoplanet is also likely a Hycean world. And unlike many sub-Neptunes, scientists say that Hyceans may be habitable. In this instance, habitable means the conditions could be right for life to form. It does not mean that we are planning to send earthly life to the exoplanet. The Webb discovery is also the first time that astronomers have discovered carbon molecules in the atmosphere of a planet in its star's…