Is southwest Colorado home to an ancient astronomical observatory? The question is testing archaeological limits
This story was originally published in The Colorado Sun.
On the winter solstice in 1997, Greg Munson stood beside an unusual basin pecked into the stone along the exit trail to Cliff Palace, grandest of the cliff dwellings in southwestern Colorado’s Mesa Verde National Park.
As the sun set on the shortest day of the year, Munson, a former Mesa Verde park ranger and researcher, watched as the sun appeared to plunge into Sun Temple, an enigmatic structure perched on a promontory atop Chapin Mesa across the canyon from his vantage point.
“It was amazing to think that maybe I was the first western person to see this event in nearly 800 years and recognize it for what it was,” Munson said.
Munson and his colleagues may have been looking at one of the most advanced astronomical observatories in the ancient world, according to recent studies by data scientist Sherry Towers.
Researchers have long theorized that Sun Temple contains solar, lunar and astronomical alignments in its placement and architecture, and Towers’ research suggests it could be far more complex than previously believed. But unraveling Sun Temple’s mysteries is made more difficult by the troubled history between researchers and the descendants of the people who built it.
Towers’ research uses computer modeling to theorize that Sun Temple is shot through with sight lines pointing not just to the rise and set of the sun at crucial dates, such as equinoxes and solstices, but to lunar cycles and an array of major stars that figure into Pueblo cosmology that may have its origins among the Ancestral Puebloans.
Towers has also further developed theories that Sun Temple’s construction incorporates advanced geometry, including a standard unit of measurement, and walls built to the proportions of the golden rectangle and Pythagorean 3:4:5 triangles.
“It’s sheer genius,” Towers said of Sun Temple’s construction. “The architect did this with no known writing or numerical system, no computers. They laid it out with yucca cords and sticks. They were the Michaelangelo of their time.”
Mesa Verde National Park, established in 1906, features some of the most well-preserved Ancestral Puebloan sites in the Southwest. More than 22,000 people may have lived on and around Mesa Verde at the beginning of the 1200s. But by the beginning of the 1300s, the area was depopulated, likely as a result of a prolonged drought or other social pressures. The inhabitants largely resettled in Arizona and the Rio Grande Valley of New Mexico, where their descendants live today as the Pueblo and Hopi people. (The park’s former inhabitants were once called the Anasazi, though the term – which is commonly cited as meaning “ancient enemy” in the Diné language – is considered derogatory by Pueblo people and has fallen out of use).
Mesa Verde’s crown jewels are its cliff dwellings, sprawling structures built in alcoves beneath the mesa tops, with likely uses including habitation, food storage, ceremony and ritual. More than 600 cliff dwellings are scattered throughout the park, though they represent just a fraction of the more than 5,000 known archeological sites within park boundaries.
Amid this archaeological treasure trove, Sun Temple stands out.
Built nearly 800 years ago by the Ancestral Puebloans, Sun Temple shows no signs of habitation – no hearths, no food storage, no trash middens. The D-shaped 122-foot-by-64-foot structure encloses several roofless circular rooms. They do not appear to be kivas, the subterranean rooms used for ceremonies and rituals. Nor were they tall enough to be watchtowers.
“We know it’s monumental public architecture,” said Elizabeth Dickey, Mesa Verde National Park’s head of cultural resources. “But how was it used? That we can’t say.”
Towers’ work follows earlier hypotheses about the site’s astronomical alignments, dating to the earliest modern researchers. Sun Temple was first excavated by J.W. Fewkes, a pioneering archaeologist and ethnographer who worked in the park in the early 20th century – and gave Sun Temple its modern name. Fewkes theorized that Sun Temple’s south wall was aligned to the summer solstice sunrise, though later investigation found the wall is off from the sunrise by several degrees.
Nevertheless, in the decades that followed, researchers built on Fewkes’ theories, owing in part to Sun Temple’s commanding view of the surrounding landscape, and growing awareness of the Ancestral Puebloans’ knowledge of astronomy.
Munson, who along with other researchers surveyed Sun Temple in the 1990s and 2000s, studied the alignment between the winter solstice sunset and the pecked basin at Cliff Palace across the canyon.
Towers, who built on work by Munson, Kim Malville and Dr. Jonathon Reyman, said her research brings a new data-driven, analytical approach that has been lacking in archeoastronomy — the study of how ancient people observed the heavens.
“You can find alignments in almost any building if you go looking for them,” Towers said.
To check her work, Towers created a computer model of Sun Temple, then rotated it in more than 200 configurations. She said only in its real-world positioning does Sun Temple most closely match the alignments of major stars in the mid-13th century, when Sun Temple is believed to have been built.
As her research has broadened, Towers said she believes many sites around Sun Temple may hold more astronomical alignments. From a boulder covered in ancient carvings at nearby Balcony House, Towers says the winter solstice sunrise would appear to emerge from the vertex of an L-shape formed by a cliff face and the top of Chapin Mesa across the canyon, though she has not yet had a chance to observe the phenomenon in person.
Towers acknowledges that while her research is intriguing, she has had little discourse with Pueblo and Hopi people about it.
“These places are considered sacred, and there’s a lot of trust that needs to be built to achieve that relationship,” said Towers, who is working for the Institute for Advanced Sustainability Studies in Germany. “I wish I lived in Colorado so I was in a position to work on that. Would Pueblo people see value in the work I do? Maybe, maybe not.”
Living, breathing places
Observing the movement of the heavens has been important to Pueblo and Hopi people throughout their known history, said Phillip Tuwaletstiwa, a Hopi geodesist.
“There were very precise ways of tracking the sun,” Tuwaletstiwa said. “The job fell to a man our people called the Sun-Watcher, who observed the solar journey.”
Observing the sun was important timekeeping for both agricultural and ceremonial functions, he said, calling the solstices – the longest and shortest days of the year – important dividing lines.
“The sun actually appears to stand still for a few days on either side of the solstice,” he said. “Pinpointing the exact day can be tricky. In our communities, on the winter solstice, we worry. If we aren’t walking the proper path, following the Hopi way, will the sun leave its winter house? It’s a period of apprehension. When it moves after a day or two, there’s a sigh of relief.”
Observing the movements of the sun and moon demonstrate a fundamental Hopi belief in the dualities of existence, Tuwaletstiwa said.
“Shadow and light, birth and death, sun and moon,” he said. “The sun is predictable, steady. It comes up every day, and if you watch its movements for a year, you’ve nailed it. The moon is nothing like that. It appears and disappears, and its full cycle across the sky, what’s called the lunar maximum and minimum, takes years to observe. The opposites in nature help balance each other.”
Tuwaletstiwa, as a geodetic surveyor, helped measure the orientation of ancient buildings in Chaco Canyon, a major Ancestral Puebloan cultural center in northwestern New Mexico. His measurements helped form the underpinning of research hypothesizing that Chacoan buildings were also built around numerous astronomical alignments.
He hasn’t made up his mind on Towers’ theories, saying the Sun-Watcher system was so effective without advanced architecture that he believes sites like Sun Temple — or the Sun Spiral, an apparent astronomical observatory on Fajada Butte in Chaco Canyon — may have been places for communities to collectively celebrate solar and lunar cycles rather than to strictly measure points on the calendar, such as the winter solstice on Dec. 21 this year.
The cyclical nature of time speaks to a mindset Tuwaletstiwa wishes modern researchers could better grasp: that to Pueblo and Hopi people, places like Mesa Verde are not abandoned.
“We don’t like that word, abandoned,” he said. “We don’t think in terms of the time between events. We have migrated many times. We didn’t vanish. We were many places before Mesa Verde, and many places after. I visited the veterans’ cemeteries in Normandy, and I treated them with respect and gratitude. In Chaco and Mesa Verde, those are my ancestral people. I need to treat them with respect as well. To us, these are living, breathing places.”
Tuwaletstiwa said it’s difficult to conclusively speak to the connection between modern Hopi and Pueblo astronomical observances and those of the Ancestral Puebloans, because there are dozens of beliefs and customs among different clans and groups.
And yet, between the analytical nature of archaeology and the intimate nature of Indigenous heritage and spirituality, Tulawetstiwa sees another complementary duality.
“When we talk about Mesa Verde, tree ring studies, carbon dating and DNA are one side, and the stories and spirits of Native people are on another side,” he said. “They can inform each other. I don’t see them as in conflict.”
Drawing archaeology and ethnography closer together is an essential task to understanding places like Sun Temple, said Munson, the researcher whose studies helped inform Towers’ work.
“The architecture, the way things were built, that’s the ‘how,’” Munson said. “The ethnography, the people, that’s the ‘why.’ Without the why, there’s now how.”
Munson founded the Society for Cultural Astronomy in the American Southwest, or SCAAS, an organization that invites Indigenous scholars to participate in archeoastronomy research. The group is also raising funds to preserve and digitize Fewkes’ work, which includes significant ethnographic resources recorded at the tail end of the 19th century.
Repairing damaged trust
Though the distance between archaeologists and the descendants of Ancestral Puebloans is narrowing, generations of strife can take time to overcome, said Tim Hovezak, the former head of cultural resources at Mesa Verde.
“To say there’s damaged trust is putting it mildly,” he said. “There’s been a long history of exploitation of people who were at the time powerless to do anything about damage to their cultural heritage.”
Though the cliff dwellings of Mesa Verde were known to the Pueblo, Hopi, Ute, Diné and other Native people for centuries, they were largely left alone. But white settlers in the late 1800s began pillaging the sites almost as soon as they discovered them, knocking down walls and hauling off wagonloads of artifacts to sell to collectors. Some early archaeologists exhumed human remains, shipping them to far-flung museums.
“Some of us are actively working to restore trust,” Hovezak said. “We’re trying to be more cognizant of Native views, and the Pueblos are becoming more proactive on their own behalf.”
Several Pueblo groups either declined to comment for this story or did not respond to requests for comment.
Some differences will likely remain, said Dickey, the park’s current head of cultural resources.
“We listen closely to descendant groups, but we can’t always enact their wishes,” Dickey said. “Some feel we shouldn’t be preserving these sites, that we should allow them to decay as Mother Nature intended. But that’s contrary to our policy to preserve these places for future generations.”
Early attempts at stabilizing sites were haphazard. Fewkes poured Portland cement atop Sun Temple’s walls, a practice that would “leave us aghast today,” Dickey said.
Dickey said the Parks Service takes a “light hand” with preservation, employing stonemasons who specialize in ancient-style stone cutting and mortar mixing.
Deciphering the mystery of Sun Temple may continue to prove elusive, Dickey said.
“A lot of the tribal members we consult with will tell us they know what these places were used for, what they mean,” Dickey said. “But they say it’s not for us to know. These are private, sacred things. Our insatiable curiosity is disrespectful to them. As scientists, we want to know everything. We want to dig until we find the answers. But sometimes, we have to learn to let go.”