The Passive Intelligence Receiver (PIR) Model: A Framework for Silent Extraterrestrial Artifacts

The Passive Intelligence Receiver (PIR) model proposes that some advanced or anomalous spaceborne artifacts may function as listeners rather than transmitters. Such systems operate silently, gathering environmental data while remaining largely undetectable. This conceptual framework reinterprets non-emissive or low-emission phenomena in both interstellar and near-Earth contexts as potentially purposeful observation systems. The paper outlines theoretical principles, possible observational signatures, and detection strategies for identifying PIR-type artifacts, providing a testable approach to unexplained spaceborne anomalies.