(GIST OF SCIENCE REPORTER) POTENTIAL LIFE ON K2-18B

(MAY-2025)

POTENTIAL LIFE ON K2-18B

Context:

Scientists have made an exciting discovery on a distant planet named K2-18b, located about 124 light-years away from Earth. Using the powerful James Webb Space Telescope (JWST), they have detected certain molecules in its atmosphere that, on Earth, are closely linked to life processes. This discovery has revived hopes in the search for life beyond our planet.

What is K2-18b?

K2-18b is an exoplanet — which means it is a planet outside our solar system. It orbits a star named K2-18; a cool red dwarf star located in the Leo constellation.
The planet was discovered in 2015 by NASA’s Kepler mission.
It lies within the habitable zone of its star. This is a region around a star where temperatures might allow liquid water to exist on a planet’s surface, which is considered an important condition for life.
K2-18b is about 2.6 times bigger than Earth and has 8.6 times Earth’s mass. It falls into a category called sub-Neptune planets — these are mid-sized planets larger than Earth but smaller than Neptune, and while we don’t have such a planet in our solar system, astronomers believe they might have hydrogen-rich atmospheres and possibly liquid water oceans underneath.

What Did the James Webb Space Telescope (JWST) Find?

JWST observed the atmosphere of K2-18b and made some intriguing findings:

It detected the presence of methane (CH₄) and carbon dioxide (CO₂) in the planet’s atmosphere.
Interestingly, it did not detect ammonia (NH₃) — a chemical whose absence supports a particular type of planet classification known as Hycean planets.

Hycean planets are hypothetical exoplanets that have hydrogen-rich atmospheres and liquid water oceans underneath. These are considered possible candidates for hosting life.
What excited scientists the most was a possible hint of dimethyl sulfide (DMS) in K2-18b’s atmosphere