A pair of researchers claim to have deciphered one of the most mysterious of the Mayan calendars, which they believe represents a 45-year cycle of our neighboring planets.  The recently published study of the 819-day Mayan calendar found it linked to synodic periods, which represent the amount of time it takes for another planet to return to the same position in the sky relative to the Earth and Sun. Mercury, for example, has a synodic period of around 116 days; Mars's is a much longer 780.  Prior research, the pair wrote, tried to show planetary connections to the 819-day calendar, which is divided into four color-directional parts.

http://klse.i3investor.com/web/blog/detail/future_tech/2023-04-22-story-h-272495950-Boffins_think_they_ve_decoded_mysterious_819_day_Mayan_calendar

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