Mystery Sound of an Unidentified Anomalous Phenomenon

The <a href="https://www.worldscientific.com/doi/10.1142/S2251171723400056" rel="noopener ugc nofollow" target="_blank">acoustic monitoring, omni-directional system (AMOS)</a> of the <a href="https://projects.iq.harvard.edu/galileo/home" rel="noopener ugc nofollow" target="_blank">Galileo Project</a> is a passive, multi-band, microphone suite designed to aid in the detection and characterization of aerial phenomena. Acoustic monitoring augments the Project’s cameras by providing an independent signal with which to validate the identification of known and unknown phenomena. With it, the nonstop movie of the sky includes both images and sound. The AMOS system spans infrasonic frequencies down to 0.05 Hertz, all audible frequencies and ultrasonic frequencies up to 190 kilohertz. It uses three distinct systems with overlapping bandwidths: infrasonic (0.05–20 Hertz), audible (10 Hertz — 20 kilohertz), and ultrasonic (16– 190 kilohertz). The sensors allow AMOS to monitor the vast range of sounds produced by natural and human-made aerial phenomena, and to characterize novel sources. Interestingly, natural selection favored the audible range for humans because low frequency sounds carry little information due to their long wavelength and high frequency sounds are attenuated by the viscosity of air. <a href="https://avi-loeb.medium.com/mystery-sound-of-an-unidentified-anomalous-phenomenon-09d1cb461cd2">Website</a>