Signs of life on K2-18b!

A Cambridge team studying the atmosphere of a distant exoplanet called K2-18b has detected signs of molecules which on Earth are only produced by simple organisms.

About K2-18b

• K2-18b is an exoplanet 124 lightyears away in the constellation Leo, orbiting the star K2-18.
• First discovered by Kepler in 2015.
• It’s 5.2 times wider and ~9 times more massive than Earth.

Atmospheric Clues:

• 2019 (Hubble): Detected water vapor.
• 2023 (JWST): Detected carbon dioxide and methane — key building blocks of life.
• Now (Cambridge team): Found signs that could point to dimethyl sulphide (DMS) or dimethyl disulphide (DMDS) — on Earth, these are only made by simple marine life, like phytoplankton and bacteria.

Why It’s Exciting:

• These compounds could be biosignatures — possible indicators of life.
• K2-18b receives similar radiation from its star as Earth does from the Sun.
• The absence of ammonia may suggest the presence of a liquid ocean absorbing it — further hinting at potentially Earth-like conditions.

Caution Flags:

• The detection of DMS or DMDS is not yet confirmed — alternative, abiotic explanations (non-life processes) are still on the table.
• There’s debate over the planet’s composition, and how conclusive the data really is.

(Source: BBC)