$$\require{cancel}$$

# 2.25 Mayan Astronomy

The highest levels of astronomical knowledge were reached in Mesoamerica around 400 A.D. by the Mayans. They developed a written language based on glyphs or pictures, used a complex and accurate calendar, recorded positions of planets, and predicted eclipses. Mayan astronomy was well organized and state-supported. Rulers used astronomical knowledge to decide when to wage war, perform sacred rituals, marry, or ascend the throne. This was a form of astrology. One inscription records a conference of astronomer-priests at Copan, Honduras (probably on May 12, 485) to discuss the calendar system.

Location of Mesoamerica. Click here for original source URL.

The Mayans passed on much of their astronomical observations and other knowledge to later cultures. Much of the Mayan knowledge was lost, however, after Spanish priests burned most of the Mayan manuscripts in 1562 because they believed them to be sacrilegious. One of three priceless Mayan manuscripts that still survive is a record of solar eclipses, the motions of Venus, and other astronomical data. Some of the major observatories of Mesoamerica have survived to the present day and can be visited.

Chich?n Itz? Mayan observatory. Click here for original source URL.

The Mayans devised a unique calendar, which was still in use when the Europeans arrived (and was more accurate than the calendar the conquerors brought with them). The Mayans celebrated the beginning of the New Year on July 26! What could have led them to this choice? The Sun can pass directly overhead at noon in the tropics, but not in Europe. Perhaps because dense jungle obscured the horizons, zenith observations were particularly important to the Mayans. Near the latitude of a major Mayan observatory, Edzna, in the Yucatan peninsula, the Sun passes through the zenith at noon on July 26. Recent archaeological studies show that Edzna was a major city of some 20,000 people in the first few centuries A.D. In the courtyard in front of the main five-story pyramid, a cleverly designed stone pedestal allowed priests to measure the important "New Year's Day" when the Sun passed through the zenith. Probably it was in or near this prehistoric city that early Mayan astronomers first selected, and then commemorated, July 26 as their New Year's Day.

Mayan astronomy is perhaps the most fascinating example of incipient Native American science. Since it survived until historic times and produced written records of complex planetary observations, astronomical conferences, eclipse predictions, and calendars, it is frustrating and sad that so much of it was lost. We may never know how the Mayan priests visualized the cosmos.