The exoplanet known as K2-18 b was discovered with the Kepler Space Telescope in 2015. It orbits an M dwarf star in the constellation Leo. It’s 124 light-years away from Earth.
Multiple news agencies recently reported on the news from researchers using the James Webb Space Telescope to take a closer look at this intriguing exoplanet.
Early this year several researchers made statements on recent Webb findings that suggest a planet perhaps friendly to life, or even containing life, have sparked recent discussions.
Here is how NASA describes it: “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.”
No. We haven’t found signs of life on K2-18 b. Just as the numerous claims of astronomers discovering “exoplanets just like Earth” have wishfully jumped the gun, some astronomers are a little ahead of the game again.
The planet’s spectrum is tantalizing to some and much ado about nothing to others.
It is rich in hydrogen, unlike our primarily nitrogen atmosphere. Some planetary scientists believe it’s likely that K2-18 b has liquid oceans, which might increase the possibility of life.
Last year researchers found evidence of carbon dioxide and methane in the spectrum, and this again could point toward a living ecosystem on the world.
Further, last year observations revealed dimethyl sulfide, a compound that on Earth is produced largely by phytoplankton. But the data are inconclusive.
Additionally, even if we were absolutely sure that K2-18 b had a hydrogen atmosphere and a surface ocean of water, neither of them — separately or together — is tantamount to the discovery of life.
All the discovery of those two things would say is that the planet is potentially habitable for some kind of life as we understand it, certainly not that it is inhabited by any life, Earth-like or otherwise.
I also want to highlight the fact that the detection of dimethyl sulfide (that tantalizing biomarker of life) is not even a firm finding at all! Straight from this paper’s abstract, “the spectrum also suggests potential signs of dimethyl sulfide.”
Take note of that wording: suggests potential signs. I just want to reiterate that this means dimethyl sulfide has not yet been unequivocally detected.
