14 DAY TRIAL // Researchers have discovered the oldest solar observatory in the Americas in 2,300 years old pre-Inca ruins.
The authors found that the large Thirteen Towers of Chankillo (a ruin north of Lima), made of stone and positioned in a line, were employed for marking the sun's position throughout the year-an activity that was part of the sun-worshipping culture of the Inca, the study authors said.
"This is the oldest known example of landscape timekeeping in the Americas," said Ivan Ghezzi, lead author of the study and an archeologist at the Pontifical Catholic University of Peru. The Inca Empire, which emerged in the region around A.D. 1200, were renown sun-worshipers who tracked - using sets of pillars - the positions on the horizon where the sun rose and set.
The Spanish conquistadors destroyed all these markers in the mid 16th century to undermine the power of the Inca Empire. "Astronomy was the backbone of the political and ideological system that supported the authority of the [Inca] rulers," Ghezzi said.
The Chankillo observatory functioned between 300 B.C. to A.D. 1, so its users were an unidentified pre-Inca culture. The other similar site in the Americas is located on the Island of the Sun in Lake Titicaca, on the border between Bolivia and Peru, harboring the remains of a pair of pillars from the 15th or 16th century which were indeed employed by the Inca to mark the solstices. "Now we know how far back the solar cult goes," said Ghezzi.
The Chankillo towers vary from 7 to 20 feet (2 to 6 meters) high and are evenly spaced, about 15 feet (5 meters) apart. "They seem to be marking regular divisions of the year for a solar calendar," said Ghezzi.
One of the neighboring edifices presented an architectural peculiarity: a 40 m (120 ft) long corridor along the side without any windows or doors into the main edifice. "The best explanation for that architectural space is it led people to an observation point to have a full view of the towers," said Ghezzi.
All around the year, the horizon points where the sun rises and sets describe an arc, which was observed in the easiest way only from the vantage point at the opening of the corridor. The opening of the corridor might have been a ceremonial site where people made offerings, as many artifacts ritually buried on that point indicate.
Another observation point on the other side of the ridge might have been used to watch the setting sun. "Individuals with the status to access [these observation spots] and conduct ceremonies would have had the power to regulate time, ideology, and the rituals that bound this society together," wrote Ghezzi and and archaeoastronomer Clive Ruggles of the University of Leicester, England, the other author of the study.
"With the abundant evidence for Inca interest in astronomy, and for its use in social organization, archaeologists have long suspected that earlier cultures also may have engaged in such activities," said David Dearborn, a physicist at Lawrence Livermore National Laboratory in California who studies ancient astronomy.
In May 2006, a team led by Robert Benfer of the University of Missouri discovered the oldest astronomical observatory in the Western Hemisphere at another site near Lima, Buena Vista, which outdates Chankillo by 1,900 years, being 4,200 years old, but the study is not published yet.