While many scientists believe life is widespread in the universe, confirming its existence remains a major challenge. A new study proposes a novel approach: instead of analyzing individual exoplanets, researchers should compare atmospheric biosignatures across entire planetary systems to identify anomalies that may indicate life.

Since most planets in a system are likely lifeless, their collective atmospheric data could help identify unusual worlds that stand out – much like Earth’s oxygen-rich atmosphere contrasts with Mars and Venus.

The research suggests establishing an “abiotic baseline” for systems like TRAPPIST-1, which contains seven Earth-sized exoplanets. By analyzing all planets simultaneously, astronomers could spot statistical outliers with suspicious gas combinations – such as oxygen and methane coexisting – that might indicate biological activity.

While no single molecule proves life, this comparative approach would help prioritize the most promising targets for further study. The method isn’t foolproof but could help prioritize targets in the search for extraterrestrial life. The method could be tested soon with advanced telescopes like James Webb Space Telescope, potentially making the first convincing detection of life beyond Earth.

The technique acknowledges that biosignatures can have non-biological explanations, but argues that a planet showing multiple anomalies compared to its neighbors presents a much stronger case for hosting life.