New Yardstick for Life: Complexity Over Signatures in Exoplanet Atmospheres

Astrobiologists propose Assembly Theory as an Earth-agnostic metric for detecting life on exoplanets, evaluating how hard molecules are to assemble rather than simply listing atmospheric species. A high assembly index and interconnected chemistry would signal life, avoiding many Earth-centric false positives. Comparing Earth, Venus, and Mars shows Earth as the most chemically diverse, and the method would yield a continuous life-likelihood score obtainable from infrared spectra, compatible with NASA’s Habitable Worlds Observatory.