K218b: Scientists say alien life may be present on planet

In a groundbreaking discovery, scientists have announced compelling evidence that extraterrestrial life may exist on K2-18b, an exoplanet located approximately 124 light-years from Earth.

Researchers from Cambridge University revealed they are 99.7 per cent confident that signs of life have been detected on the planet, sparking widespread excitement in the scientific community.

What is K2-18b?

K2-18b is an exoplanet—a planet beyond our solar system—that orbits a red dwarf star known as K2-18, located in the Leo constellation.

Discovered in 2015, K2-18b quickly drew attention due to its position in the “habitable zone”—the ideal region around a star where temperatures may allow liquid water to exist on a planet’s surface.

Classified as a “super-Earth” or “sub-Neptune”, K2-18b is roughly 8.6 times more massive than Earth and about 2.6 times its size. Its density suggests the presence of a thick hydrogen-rich atmosphere that may surround a rocky or icy core.

Could There Be Life?

In April 2025, scientists using the powerful James Webb Space Telescope—launched in December 2021—detected chemical signatures in K2-18b’s atmosphere that hint at possible biological activity.

Among these were dimethyl sulfide (DMS) and dimethyl disulfide (DMDS)—molecules which, on Earth, are almost exclusively produced by living organisms, particularly marine phytoplankton (tiny algae in the oceans).

The presence of these chemicals has led scientists to believe that K2-18b may host a hidden ocean beneath its atmosphere—possibly filled with microbial life. The evidence points toward an environment that could, in theory, be “teeming” with alien microbes.

This extraordinary finding could mark a major turning point in the search for life beyond Earth, offering hope that we are not alone in the universe.