Biosignatures

From observation to inference

A biosignature is a possible sign of past or present life. Its scientific value depends on how it was measured and on the surrounding environment. Interpretation combines biological knowledge with chemistry, geology and observational limitations.

Testing alternatives

An organic compound or an interesting atmospheric signal can have nonbiological explanations. Life detection therefore requires a chain of evidence, not a label attached to one unusual measurement.

Source chronology

Dates below describe source publication, which may differ from the date of an observation or event.

Connected knowledge

Source trail

Use the Primary sources tab to inspect the original records, publication dates and provenance.