The James Webb Space Telescope (JWST) has made a groundbreaking discovery by detecting an organic molecule in the atmosphere of a distant exoplanet. This finding has sparked excitement in the scientific community as it hints at the potential existence of life thriving in a vast global ocean on this remote celestial body. However, further observations and research will be necessary to confirm this tantalizing possibility.
The exoplanet in question is known as K2-18 b, and it is believed to orbit within the habitable zone of an alien star situated approximately 120 light-years away from Earth in the Leo constellation. K2-18 b is considerably larger than Earth, with a size roughly 2.6 times that of our home planet. Prior observations of this distant world had led some scientists to classify it as a member of a newly identified category of potentially habitable planets collectively referred to as ‘Hycean worlds.’
Hycean worlds are a unique class of celestial bodies that resemble mini-Neptunes. They possess atmospheres rich in hydrogen and are characterized by expansive, planet-spanning oceans capable of sustaining microbial life. The recent study of K2-18 b, utilizing data collected by the JWST, has shed more light on the true nature of this alien planet.
Typically, observing sub-Neptune worlds like K2-18 b is immensely challenging due to the intense radiation emanating from their parent stars. However, in this particular case, astronomers managed to capture light originating from the parent star that had traversed through the exoplanet’s atmosphere. This achievement was made possible by the JWST’s extended wavelength range and exceptional sensitivity.
Nikku Madhusudhan of the University of Cambridge, the lead author of the study, emphasized the significance of this achievement. Madhusudhan stated, “This result was only possible because of the extended wavelength range and unprecedented sensitivity of Webb, which enabled robust detection of spectral features with just two transits. For comparison, one transit observation with Webb provided comparable precision to eight observations with Hubble conducted over a few years in a shorter wavelength range.”
By scrutinizing the chemical signature present in the starlight, the research team managed to identify the presence of methane and carbon dioxide in the atmosphere of K2-18 b, reinforcing the notion that it could indeed be a Hycean world. Additionally, the astronomers stumbled upon evidence of a rare molecule called dimethyl sulfide in the light spectrum. On Earth, dimethyl sulfide is exclusively produced as a byproduct of life, primarily by marine bacteria and microscopic organisms like phytoplankton.
This discovery of dimethyl sulfide serves as a robust indicator for the potential presence of life on K2-18 b. However, researchers caution that further observations with the JWST will be imperative to confirm the presence of this biomarker in the planet’s atmosphere. There’s also the possibility that the intense radiation from K2-18 b’s parent star may have rendered its potentially enormous ocean too hot to support life as we understand it.
The team responsible for the JWST intends to conduct follow-up observations of this oceanic exoplanet using the telescope’s Mid-Infrared Instrument (MIRI). These additional observations could provide valuable insights into the true nature of this alien world, furthering our quest to understand and identify habitable environments and potentially even life beyond our own planet.
In conclusion, the James Webb Space Telescope’s recent discovery on K2-18 b represents a significant step forward in our search for life on exoplanets. While there is still much to learn and confirm, this finding underscores the importance of exploring diverse habitable environments in our quest to answer one of the most profound questions: are we alone in the universe?
Our @NASAWebb telescope detected carbon dioxide and methane in the atmosphere of a planet orbiting a faraway sun. The planet might have an ocean, but more observations are needed to determine whether it could support life: https://t.co/J8ub8PqwMG pic.twitter.com/SbgHjOO9Hv
— NASA (@NASA) September 11, 2023