Julia DeMarines Proposes Noosignatures to Fill Astrobiology's 3.5 Billion-Year Detection Gap
Updated
Updated · Universe Today · Jul 13
Julia DeMarines Proposes Noosignatures to Fill Astrobiology's 3.5 Billion-Year Detection Gap
1 articles · Updated · Universe Today · Jul 13
Summary
A new arXiv paper by astrobiologist Julia DeMarines introduces “noosignatures” as detectable traces of intelligence that sit between standard biosignatures and advanced technosignatures.
The idea targets the long span between microbes and radio-capable civilization—about 3.5 billion years on Earth—where intelligence may alter a planet without producing obvious technological emissions.
DeMarines defines noosignatures as structured traces left by minds on a medium, from stone tools to complex communication, and points to Assembly Theory as one way to test whether an object required intelligent construction.
Earth examples include 3.3 million-year-old Lomekwian tools and agriculture’s impact on the nitrogen cycle about 8,000 years ago, both predating radio signals by millennia.
The framework remains preliminary: noosignatures can decay, natural self-organization may mimic them, and the field is barely represented—this year’s Astrobiology Science Conference had 23 biosignature sessions, one technosignature session and none dedicated to intelligence research.
Could a new theory finally help us find evidence of long-dead alien civilizations?
How can scientists distinguish an alien artifact from a complex rock light-years away?
Beyond Biosignatures and Technosignatures: Noosignatures and Assembly Theory in the Search for Non-Technological Intelligence
Overview
The search for extraterrestrial life has mainly focused on biosignatures—chemical or physical traces of simple life—and technosignatures, which are signs of advanced technology. However, there is a critical gap in astrobiology: the 'missing middle ground' between these two extremes. Few scientists have explored how to detect life that is intelligent but not yet technological. This gap is reflected in scientific meetings, where research on intelligence is underrepresented compared to biosignatures and technosignatures. Addressing this imbalance could help us discover new forms of life that current methods might miss.