UFO

Any object or optical phenomenon observed in the sky which cannot be identified, even after being thoroughly investigated by qualified people. A fuller definition was given by Dr. J. Allen Hynek, late astronomer, U.S. Air Force consultant and UFO proponent, as "the reported perception of an object or light seen in the sky or upon the land the appearance, trajectory, and general dynamic and luminescent behaviour of which do not suggest a logical, conventional explanation and which is not only mystifying to the original percipients but remains unidentified after close scrutiny of all available evidence by persons who are technically capable of making a common sense identification, if one is possible."

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