Modeling the Law of Times

Julio Plaza del Olmo


The Law of Times is a constant pattern present in every catalog of Unidentified Flying Object (UFO) sightings that describes the number of sightings occurring at a certain hour of the day. It shows that most sightings occur at night, reaching a maximum at about 21 h, and sometimes a secondary peak at about 2–3 h, whereas for daylight hours the percent of cases is low. It has long been suspected that the decrease in sightings during the night is due to social factors such as people staying indoors and thus not being able to witness UFOs. An increase in sightings occurs at earlier or later hours in the same way that the sunset time varies during the year. Taking into account these features, this paper develops a mathematical model to reproduce the Law of Times. It is based on astronomical factors such as the altitude of the Sun and the Visual Limiting Magnitude that relates to the probability of a phenomenon being visible; and a second factor related to the social habits of the population, accounting for their availability to witness the phenomenon. These two factors alone can accurately reproduce the main peak at 21–22 h of the Law of Times.

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