Maya wall calendar discovered

Ancient astronomical records found on room’s painted walls

Astronomical tables dating to the golden age of Maya civilization have unexpectedly come to light on the walls of a roughly 1,200-year-old room in Guatemala.

HOME IMPROVEMENT Inside a structure excavated at the ancient Maya city of Xultun, researchers found walls bearing astronomical tables and paintings of big-wigs such as these. Tyrone Turner, copyright 2012 National Geographic

Hieroglyphs and numbers painted on the stucco walls of a structure built during the Classic Maya civilization record cycles of the moon, and possibly Mars, Venus and Mercury, say Boston University archaeologist William Saturno and his colleagues. Excavations in 2010 and 2011 at Xultun, a Maya site first described in 1915, revealed that painted murals once covered three of the room’s inside walls and its vaulted ceiling.

Until now, Maya astronomical tables were known from bark-paper books — known as the Dresden Codex — created 400 years or more after the ancient civilization’s demise around 900, the researchers report in the May 11 Science.

“The Xultun finds provide the first direct evidence of astronomical information from the summit of Maya glyphic literacy, the Classic period,” remarks archaeologist Stephen Houston of Brown University. He calls the recording of astronomical tables on walls rather than in a book “baffling, even astonishing.”

One Xultun wall section contains bar-and-dot numbers in columns that resemble astronomical tables in the Dresden Codex. Moon hieroglyphs appear atop at least five columns. These tables record lunar months, in six-month sets, over roughly 13 years. The number 13 held special significance for organizing the Maya calendar.

“It’s as though someone today took a university textbook and painted it on a wall,” says archaeologist Charles Golden of Brandeis University in Waltham, Mass.

Similar numerical records at Xultun and in the Dresden Codex suggest that the Maya passed and revised astronomical information over many generations after the Classic collapse, Saturno says.

A table of solar and lunar eclipses in the Dresden Codex starts in the mid-8th century, indicating that the document was based on information from at least 50 years before the Xultun finds, anthropologists Harvey Bricker and Victoria Bricker, both of Tulane University in New Orleans, wrote in a joint email.

Referring to Dresden Codex calculations of a starting time for astronomical tables, the Brickers say that corresponding numbers at Xultun record a period of almost exactly 198 eclipse seasons. Each 37-day eclipse season contains at least one solar and one lunar eclipse.

“Ritual specialists at Xultun, like the authors of the Dresden Codex, were concerned not only with the moon’s monthly cycle but with the much longer cycle of solar and lunar eclipses,” the Brickers conclude. So the Xultun Maya used walls as scratch pads to construct astronomical records, the Brickers suggest.

A plaster bench in the Xultun room, resembling benches Maya rulers used at royal court meetings, sits in front of a painting of a king talking to a kneeling attendant, says archaeologist David Freidel of Washington University in St. Louis. Classic Maya vases show similar court scenes, sometimes with humans and gods writing on tablets, Freidel says. No pottery depictions of anyone writing on walls have been found.

Bruce Bower has written about the behavioral sciences for Science News since 1984. He writes about psychology, anthropology, archaeology and mental health issues.

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