a guide to the sky
a guide to the sky
Mayans and the cycle of Venus
By MARCELO DE OLIVEIRA SOUZA
Sky ’ s Up Editor
The Mayans ... Great astronomers of the past ... They knew precisely the cycle of Venus , a star they called Chak Ek ‘. There are six pages about the cycle in the Dresden Codex , one of the rare Mayan books that were not destroyed by the Spanish . The planet Venus is the brightest point of light in the sky after the sun and moon . It has always attracted a lot of attention . Because it is a planet located between the Earth and the Sun , it can only be observed a few hours before dawn or a few hours after sunset . Never both at the same time , or appear as a morning star or as an evening star . The Mayans knew this . According to the description in the Dresden Code the Mayans also knew the full Cycle of Venus . We now consider that Venus appears as a morning star , in the early morning before sunrise , for approximately 263 days , then remains approximately 50 days unobserved , returns for approximately 263 days as an evening star and then disappears for 8 days , returning again as a morning star and closing the cycle . We call this cycle the synodic period . The synodic period is the orbital period of a star when observed from Earth , that is , it is the period for the return of the star the same apparent position in the sky . An interesting fact is that the 263-day period is approximately our gestation period . So sometimes , and in some civilizations , the period that Venus is visible in the sky is associated with the period of pregnancy . Between two appearances as a morning star we have an approximate period of 584 days , to be more precise 583,924 days . The Mayans also realized that after five cycles of Venus , which are 2920 days ( 5 x 584 days = 2920 days ), we have eight terrestrial years ( 8 x 365 days = 2920 days ). The planet Venus begins to appear as a morning star on the same day ( with a difference of approximately two days when we consider leap years ). Due to the fact that the Mayans used a base 20 counting system , the closest to them of our century were 104 years . In this period we have 65 complete Venus cycles and there are 13 periods of 2920 days . Venus repeats its position 13 times in the sky when it appears as a morning star . It was what they called the great cycle . The number 13 refers to the large joints of the human body that were the sites of disease entry : the neck , the two shoulders , the two elbows , the two wrists , the hips ( two ), the two knees and the two ankles . The number 13 also represented
Venus Table in the Dresden Codex
COURTESY OF Sächsische Landesbibliothek – Staats – und Universitätsbibliotek Dresden
21