Scholars Uncover Ancient Maya's Astounding Ability to Predict Solar Eclipses Using 260-Day Calendar

A recent scholarly analysis, published in the journal Science Advances on October 22, 2025, has revealed the sophisticated astronomical knowledge of the ancient Maya, specifically their ability to forecast solar eclipses with remarkable accuracy. Researchers John Justeson of the University at Albany and Justin Lowry of SUNY Plattsburgh spearheaded the investigation, focusing on a cryptic eclipse table found within the Dresden Codex, a key hieroglyphic manuscript dating from the Postclassic period, approximately 1100 to 1521 AD.

The core of the breakthrough lies in a compelling mathematical correlation identified by the scholars. They established that 405 lunar months, each measuring about 29.530589 days, align nearly perfectly with 46 complete cycles of the Maya's sacred 260-day ritual calendar, known as the Tzolk'in. This intricate harmony between the lunar cycle and the Tzolk'in was the mechanism that enabled the Maya to discern the recurring celestial patterns necessary for predicting these dramatic solar events. The Tzolk'in calendar was fundamental to Maya society, governing the pace of daily life and ceremonial activities.

In their detailed scrutiny, Justeson and Lowry examined records pertaining to 145 solar eclipses visible across the Maya heartland between 350 and 1150 CE. Their research suggests that while the eclipse table in the Dresden Codex was initially intended to track lunar months, it was later ingeniously adapted for solar eclipse prognostication. This adaptation required a subtle recalibration of the table to account for the minor differences between the lunar and solar cycles, ensuring precision over long time spans.

This finding provides a significant window into the Maya's deep comprehension of cosmic rhythms and their skill in integrating different calendrical systems. The Tzolk'in calendar is thus positioned not only as a religious artifact but as an essential tool in Maya observational astronomy, deeply integrated into their spiritual and communal practices. The Maya timekeeping system was notably robust, often regarded as one of the most accurate ancient methods, utilizing the 365-day Haab' solar calendar alongside the Tzolk'in to form the 52-year Calendar Round, which managed both immediate societal needs and long-term celestial observation.