A Structured UAP Taxonomy and the Legacy of Project Sign
To the point
An organized glossary of unidentified aerial phenomena explains encounter levels, craft shapes, and alien species, and notes Project Sign (1948) with Sneider, Loedding, and Hynek, its methods (interviews, evidence, radar, astronomy), the Extraterrestrial Hypothesis debate tied to the controversial Estimate of the Situation, and Sign’s influence on later projects and modern UAP discussion.
