Archaeologists have found a small room in Mayan ruins where royal scribes apparently used walls like a blackboard to keep track of astronomical records and the society's intricate calendar approximately 1,200 years ago.
The walls reveal the oldest known astronomical tables from the Maya. Scientists already knew they must have been keeping such records at that time, but until now the oldest known examples dated from about 600 years later.
Astronomical records were key to the Mayan calendar, which has gained attention recently because of doomsday warnings that it predicts the end of the world this December. Experts say it makes no such prediction. The new finding provides a bit of backup: The calculations include a time span longer than 6,000 years that could extend well beyond 2012.
"Why would they go into those numbers if the world is going to come to an end this year?" observed Anthony Aveni of Colgate University in Hamilton, N.Y., an expert on Mayan astronomy. "You could say a number that big at least suggests that time marches on."
Aveni, along with William Saturno of Boston University and others, report the discovery in today's issue of the journal Science.
The room, a bit bigger than 6 feet square, is part of a large complex of Mayan ruins in the rain forest at Xultun in northeastern Guatemala. The walls also contain portraits of a seated king and some other figures, but it's clear those have no connection to the astronomical writings, the scientists said.
One wall has a calendar based on moon phases, covering about 13 years. The researchers said it might have been used to keep track of which deity was overseeing the moon at particular times.
Aveni said it would allow scribes to predict the appearance of a full moon, years in advance, for example. Such record-keeping was key to Mayan astrology and rituals and possibly was used to advise the king on when to go to war or how good the year's crops would be, he said.