AN OBSERVATIONAL NOTE FROM THE FIELD: LIGHT AND SHADOW PLAY AT SUMMER SOLSTICE NOON IN BANDELIER NATIONAL MONUMENT

On a field trip to Bandelier National Monument in New Mexico, the Archaeoastronomy class I once co-taught with noted Astronomer, Dr. Ron Olowin, noticed something of great moment. Serendipitously we arrived during the Summer Solstice just before noon. We were told by the National Park Service of an impressive petroglyph located on the north ridge of the canyon face, approximately 120 feet above the central ceremonial complex floor in an extraordinarily inaccessible place. In fact, the people who produced this petroglyph apparently used ropes to descend the canyon face, otherwise the rock surface would have made re-ascending an impossibility.[1] Though we were told of the petroglyph itself our group was not informed, however, of possible solar alignments apropos of this petroglyph. No one prepared us for what we were about to spontaneously witness between the 40 minutes of 11:40 a.m. and 12:25 p.m. (MST) on this Summer Solstice day.

While hiking through the ceremonial complex at Bandelier, replete with its extraordinary examples of Ancestral Pueblo architecture including large kivas and “d-shaped” stone walls (dated to AD 1150-1550), the class stopped to take rudimentary compass measurements of a probable Winter Solstice alignment detected in the ancient entrance of the main Ancestral Pueblo ruin, Tyuonyi. Standing in the middle of the Tyuonyi ruin we spotted, to the north, the petroglyph as detailed by the Park Service located high on the Frijoles Canyon rock face. The time at this particular moment was 11:40 a.m. As the sun increased in height toward its zenith a shadow began to crawl across the face of the petroglyph. It was during this time that the class experienced the thrill of real-time Archaeoastronomy! We all stood in awe and wide-eyed wonder as we witnessed the subsequent ancient interplay of light and shadow.

As the shadow passed through the umbilicus of the petroglyphic disk we noticed that the entire petrogplyphic scheme was becoming completely flooded, and indeed erased, by the sun’s light. In other words, the sun’s illumination totally obliterated the petroglyph, rendering the artwork entirely undetectable—and this occurred exactly at Summer Solstice noon.

Worth noting in reference to our observation of this rock art display: perhaps, akin to observations made by Sofaer (2008), on Fajada Butte, the ancient Ancestral Puebloans were not only accustomed to, and limited by, the utilization of shadow to produce timely rock art effects; but rather, they were also—and perhaps more importantly—acquainted with using light to produce auspicious solar coincidences. In this way light is used as a tool, with shadow, to exhibit important calendrical events. In this particular case, solar light drowned out and obscured the solar petroglyph that was normally observable in shadowy conditions. The effect is electric!

Furthermore, it may be vital to ask if the Ancient Puebloans were attempting to create something akin to an emotional experience in their use of light and shadow to mark celestial events. This particular petroglyph stands sentinel above a presumably ancient public space at Bandelier, and it may be that the Sun’s movements, vis-à-vis this petroglyph, were used in a public ceremonial event or set of events, allowing for the Sun’s motions to create a communal experience charged with collective emotion. (It is perhaps impossible not to project our class’ sense of wonder onto the ancient past!)

For an Archaeoastronomy class field trip nothing in the world could have been more favorable than to witness first-hand this ancient interplay of light and shadow. And this experience begs the question of whether other Archaeoastronomical treasures remain undiscovered at Bandelier, and what these treasures may uncover about the Ancestral Puebloans’ perception and use of light and shadow.  

This coming year, and every year beyond, at Summer Solstice, you can journey to Bandelier to witness the same event, and you will be blown away by the ingenuity of the ancient peoples of New Mexico and the American Southwest.

By: Tom Christian, PhD

Acknowledgments:

Special thanks to Dr. Ron Olowin, who passed away in 2017. Ron provided the inspiration for the writing of this tiny piece, and his astronomical expertise made the viewing of this solar event possible. Special thanks too to Dr. Paul Zolbrod who always provided academic support for every kind of reverie, along with encouragement in pursuing exciting projects. Finally, I would like to thank and acknowledge our wonderful archaeoastronomy class comprised of: Marti Brittenham, Janeen Counts, Kristin Engelbrecht, John Garth, Stu and Kat Haskins, Mark Meyers, Tom Meyers, Tim O’Brien, Joe Stroud, and Steve Knowles.

[1] It is noted in the rock art literature that extreme heights and general inaccessibility of certain rock art sites may have added to the “mystery” and wonder of such indigenous artwork sites (cf. Christian (2012); Jett (1984).