VISUAL OBSERVATION OF SATELLITES / WORKING PAPER NO. 18: PROJECTED SHAPES/SHADOWS, FLUORESCENCE, LUMINESCENCE & SONOLUMINESCENCE

This document, titled DIS Scientific & Technical Memorandum 55/2/00, serves as a technical reference for the analysis of Unidentified Aerial Phenomena (UAP) reports. It is divided into two primary sections: the visual observation of satellites and an examination of projected shapes, shadows, and various luminescence phenomena. The first section provides a detailed guide on how satellite characteristics—such as orbital period, inclination, re-entry, and brightness—can lead to misidentification as UAP. It includes mathematical and graphical aids for calculating satellite visibility, shadow heights, and orbital tracks, specifically tailored for observers in the United Kingdom. The document emphasizes that many UAP reports are likely misidentified satellites, particularly when observers are unaware of the specific conditions required for satellite visibility, such as the sun's position relative to the horizon and the observer's location in shadow. The second section, Working Paper No. 18, explores the physics behind visual anomalies. It discusses how opaque objects can cast shadows that appear as silhouettes, how aircraft shadows can be projected onto clouds, and the potential for 'rainbow-like arrays' created by sunlight passing through aircraft windows. Furthermore, it delves into the science of fluorescence, luminescence, and sonoluminescence. It suggests that some reported UAP, such as 'highly charged balls' or sources of colored light, might be explained by atmospheric gas absorption, aerosol fluorescence, or the production of light via sonoluminescence in gas bubbles. The document concludes that these natural and man-made physical processes provide plausible explanations for a significant proportion of UAP reports, noting that the lack of measurement technology often hinders the definitive identification of these phenomena.