As humanity searches the cosmos for alien life, one of the most promising strategies involves detecting biosignature gases in exoplanet atmospheres. These trace elements – like oxygen, methane, and water vapor – may indicate biological activity. Thanks to recent advancements in astronomical technology, especially the James Webb Telescope, we’re now better equipped than ever to detect these elusive signs of life.

Biosignature gases are molecules whose presence in a planetary atmosphere could indicate biological processes. On Earth, gases like oxygen (O2) and methane (CH4) are primarily produced by living organisms. When found together on another planet, they could suggest an imbalance that might be due to life.

The James Webb Space Telescope (JWST) has revolutionized exoplanet atmosphere detection. By analyzing starlight passing through a planet’s atmosphere during a transit, JWST can identify specific spectral signatures that match molecules like water vapor, methane, and carbon dioxide.

In 2023, JWST detected potential biosignatures in the atmosphere of exoplanet K2-18b, including dimethyl sulfide, a molecule produced by marine life on Earth. While not conclusive, such findings mark important steps toward understanding exoplanetary habitability.

Interpreting these signals is complex. Methane, for example, can be generated by volcanic activity, not just life. Researchers cross-reference multiple gases to improve confidence that the source is biological. With tools like JWST, the field of biosignature gas detection is maturing. By identifying combinations of molecules like oxygen, methane, and water vapor, scientists are getting closer to answering one of humanity’s oldest questions: are we alone?