Ancient Inca astronomers were tracking the sun and planets centuries ago. Now scientists have unearthed an observatory on an island. Why was the center of science isolated from society?
University of Illinois at Chicago archaeologist Brian Bauer and colleagues have unearthed artifacts from sites in South America that shed light on how the Inca organized their sun-worship rituals and how they physically kept track of the sun’s movements.
According to Bauer, “many scholars of Latin American antiquity believe that the Inca built large stone pillars to record the sun’s horizon location at the June and December solstices, but archaeologists had not found physical evidence of the pillars and there had been no detailed investigation into the organization of the solstice rituals” — until now.
During a survey of pre-Hispanic sites on the Island of the Sun, in Lake Titicaca, Bauer and colleagues David Dearborn of Lawrence Livermore National Laboratory and graduate student Matthew Seddon of the University of Chicago discovered the remains of two stone pillars. They also found a large platform area just outside the walls of a sanctuary on the island.
Archaeological and astronomical research, which the team presents in the Sept. 24 issue of Latin American Antiquity, suggests the Inca used the site to support the elites’ claim to power through elaborate solar rituals, perhaps using two-tiered worship.
In the early 15th century the Inca empire — the largest state to develop in the Americas — expanded into the Lake Titicaca region in modern-day Peru and Bolivia and usurped the Island of the Sun from local control. The island and a sacred rock, which locals believed was the birthplace of the sun, had been the focus of worship for centuries, said Bauer. Under the Inca it became one of the most important pilgrimage centers in South America.
“The Inca nobility, as well as members of the general populace, journeyed to the island to worship and make offerings in a sanctuary plaza next to the sacred rock,” said Bauer.
The team’s research indicates that, on the June solstice, the Inca king and high priests of the empire assembled in a small plaza beside the sacred rock to witness the dramatic setting of the sun between the stone pillars. Their findings also indicate that, as the elites paid homage to the sun from within the sanctuary, lower-class pilgrims observed the event from a second platform outside the sanctuary wall. From the perspective of the lower-class pilgrims, the sun set between the stone pillars and directly over the ruling elite, who called themselves the children of the sun.
“We’re proposing that the platform outside the sanctuary walls represents a segregation of the elite and non-elite classes of sun worship,” said Bauer. “This adds a new dimension to the practice of the solar cult that was not distinctly recorded in accounts of similar state rituals in the imperial capital, Cusco.
“While both groups participated in solar worship, the non-elites simultaneously offered respect to the sun and the children of that deity. This physical segregation emphasized that the Inca alone had direct access to the powers of the sun,” he said.
The researchers illustrate the layout of the Inca structures in a map. The two stone pillars were erected on a natural ridge 600 meters to the northwest of the sacred rock. The plaza adjacent to the sacred rock was rectangular in shape, roughly 80 meters long and 35 meters wide, with the long axis pointing in the direction of the June solstice sunset. A sanctuary wall to the south and east blocked access to the site, which could only be reached through a gate. The secondary plaza, accessible to all pilgrims, was just outside the sanctuary wall and about 250 meters southeast of the sacred rock plaza.
Bauer said the remnants of stone pillars are similar to pillars around Cusco, which were described by several Spanish chroniclers of the 16th century. Those pillars were large enough to be seen against the setting sun at a distance of 15 kilometers. One such set of pillars marked where the sun sets at the June solstice, which is the northernmost point at which the sun crosses the! horizon. Unfortunately, said Bauer, a combination of post-conquest looting and recent urban growth in the Cusco valley has destroyed the area where the Cusco pillars once stood.
Bauer and Dearborn’s research on the Island of the Sun is a continuation of their long-standing joint research on Inca astronomy. They are the authors of Astronomy and Empire in the Ancient Andes (University of Texas Press), which examines the origins and organization of Inca astronomy in Cusco.
“The findings from the Island of the Sun is the first discovery and documentation of similar pillars outside the imperial capital of the Inca,” said Bauer.