Chaco Canyon petroglyphs. Photo: University of Colorado Boulder

Millions of smartphone cameras will be pointed skyward midday on Aug. 21 as the moon passes between the Earth and sun, creating a ring of light that will leave many in awe in North America.

But the total solar eclipse pictures that will soon circulate Facebook, Twitter and Instagram are prefigured by a petroglyph carved meticulously in stone by an Anasazi watcher of the skies during the total solar eclipse of July 11, 1097.

During the great time of unrest, the Anasazi artist was attempting to document what may have been a crucial celestial event during a desperate time for his or her people, according to analysis.

The petroglyph, found at the famed Chaco Canyon site in New Mexico, was first noticed on a free-standing rock called the Piedra del Sol. It was discovered in 1992 during a field school trip led by J. McKim Malville of the University of Colorado at Boulder and James Judge of Fort Lewis College.

Malville and colleague Jose Vaquero of the Universidad de Extremadura wrote a paper outlining the investigation of the rock carving, which was published in the journal Mediterranean Archaeology and Archaeometry in 2014.

They found that the petroglyph appears to show a solar corona consistent with a coronal mass ejection. Such an ejection would have to happen during a time of heightened, if not maximum, solar activity. They and other scientists found, using cosmogenic radionuclides and isotopes, that the maximum occurred in 1098 C.E., just the year after the solar eclipse.

“The eclipse of 1097 C.E. occurred during a period of high solar activity, consistent with the interpretation of the petroglyph as a representation of solar corona during the solar eclipse of that year,” they write.

The eclipse came at a time of great upheaval at Chaco. A decade-long drought had apparently destabilized agriculture – and also the institutions that held the society together, according to the paper. Mass migration was decreasing the population – and the sun’s display may have added to fears about the future, the modern-day scientists write.

“The sun must have been an object of great important, and its eclipse, which would have been observed over a large portion of the Chacoan sphere of influence, could have further diminished the credibility of sun rituals performs in the canyon,” they write. “The eclipse may thus have been more significant than a puzzling event in the sky. Because the eclipse was concomitant with environmental and social changes in the canyon, it may (have) warranted a recording on the rock of Piedra del Sol.”

The Anasazi at Chaco Canyon also are believed to have documented the supernova of 1054, in a pictograph which shows a hand, a crescent moon, and a 10-pointed star.

The solar eclipse anticipated on Aug. 21 would run across the entire contiguous 48 U.S. states, from Oregon to a gradual sweep across Idaho, Wyoming, Nebraska, Missouri, Kentucky and Tennessee, down to South Carolina – though it will be visible in virtually all the states at some point during its transit. The last appearance of a total solar eclipse anywhere in the continental U.S. was in 1979. But the last time it spanned the entire lower 48 was back in 1918, according to NASA.

The space agency has said that many of those smartphone images taken of the 2017 eclipse will be lackluster, due to lack of resolution, filters and focus.

Piedra del Sol petroglyph