Agnostic Biosignatures and Probabilistic Frameworks for Detecting Life Beyond Earth

To the point

Detecting life beyond Earth relies on agnostic indicators grounded in environmental context and evaluated for reliability, survivability, and detectability, using multiple lines of evidence and probabilistic reasoning to distinguish true biosignatures from abiotic signals, a perspective advanced by Lovelock, Sagan, Mustard, and Adlner Meadows.

Biosignature Identification and Interpretation
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Biosignature Identification and Interpretation

In order to qualify as biosignatures, these “features must be sufficiently complex and/or abundant so that they retain a diagnostic expression of some of lifes universal attributes” (Des Marais et al. 2008). Another essential characteristic is that their formation by nonbiological processes be highly improbable. Informational biopolymers like DNA or polypeptides, for example, would be examples of biosignatures that are highly unlikely to arise in the absence of biology.