James Webb Telescope Detects Possible Signs of Life on Exoplanet K2-18b

In a remarkable milestone for space exploration and astrobiology, scientists from Cambridge University have announced a significant discovery using NASA’s James Webb Space Telescope (JWST). They have detected potential biosignatures — chemicals associated with life — in the atmosphere of a distant exoplanet called K2-18b. Although the discovery is yet to be conclusively confirmed, it provides a promising lead in the ongoing quest to discover extraterrestrial life.

About Exoplanet K2-18b

• K2-18b is located 124 light-years away from Earth in the Leo constellation.
• It is approximately 2.6 times larger than Earth, categorising it as a sub-Neptune-type exoplanet.
• The planet orbits a red dwarf star, which is smaller and cooler than our Sun.
• This exoplanet lies in the habitable zone, meaning conditions could support liquid water — a key ingredient for life.

Detection of Potential Biosignatures

• Scientists found traces of Dimethyl Sulphide (DMS) and Dimethyl Disulphide (DMDS) in the planet’s atmosphere.
• On Earth, DMS is produced exclusively by marine microorganisms, making it a strong biosignature gas.
• The presence of such molecules suggests that similar microbial life might exist in the atmospheric or oceanic layers of K2-18b.

How the Discovery Was Made – Tool Used

• The research was conducted using spectral analysis via the James Webb Space Telescope (JWST).
• JWST is capable of examining infrared starlight that passes through planetary atmospheres, helping identify the chemical composition.
• By analysing light filtered through K2-18b’s atmosphere, scientists could detect trace gases linked to biological processes.

Certainty Level and Scientific Rigour

• The detection currently stands at a statistical confidence level of three sigma (99.7%).
• In scientific studies, five sigma (99.9999%) is the benchmark required to claim confirmed discovery.
• Hence, while promising, the findings are not yet conclusive and require further observations for confirmation.

Scientific Significance and Future Implications

• If further confirmed, this will be the first credible evidence of life beyond Earth.
• It will reshape our understanding of life in the universe and support theories suggesting that life may not be unique to Earth.
• The discovery could also guide future missions targeting habitable exoplanets, focusing especially on super-Earths and sub-Neptunes.