Ancient rock art in a New Mexico canyon reveals a total solar eclipse seen by Pueblo people over 1,000 years ago

  • Petroglyph in a rock at the Chaco Canyon thought to illustrate total solar eclipse
  • The carving features circular object with a solid center, and looping protrusions 
  • Experts say the event likely took place at a time when solar activity was high 
  • The researchers estimate it depicts an eclipse that passed through July 11, 1097

On August 21, a total solar eclipse will sweep through the United States, darkening skies from coast to coast as the moon passes in front of the sun.

And, as viewers look toward the sun’s tangled corona, the event could bear semblance to a scene that took place more than a thousand years before.

At New Mexico’s Chaco Canyon, researchers have discovered a petroglyph carved by the early Pueblo people that appears to illustrate a total solar eclipse.

Evidence of ceremonial practices at the site indicates that the free-standing rock may have been used for solstice-related activities, and the experts now suspect the ancient people once gathered there to watch an eclipse in the summer of 1097.

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At New Mexico’s Chaco Canyon, researchers have discovered a petroglyph that appears to illustrate a total solar eclipse (seen just below center in the image above). The researchers suspected a larger loop seen branching out from the circle could be a coronal mass ejection

At New Mexico’s Chaco Canyon, researchers have discovered a petroglyph that appears to illustrate a total solar eclipse (seen just below center in the image above). The researchers suspected a larger loop seen branching out from the circle could be a coronal mass ejection

THE CHACOAN PEOPLE

For over 2,000 years, 'Pueblo' Native American peoples occupied a vast region of the southwestern United States.

Chaco canyon in New Mexico became a major centre of ancestral Puebloan culture 1,000 years ago.

This society is now known as the Chacoans.

Chaco canyon contains large-scale public and ceremonial buildings with intricate architecture, suggesting that the culture thrived as a complex society.

But historians have struggled to identify how Chacoan society worked because they did not write.

Using masonry techniques unique for their time, the Chacoan constructed massive stone buildings (Great Houses) of multiple stories containing hundreds of rooms.

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In the petroglyph, the inclusion of several looping tendrils suggest high solar activity and even a coronal mass ejection, according to the researchers.

The free-standing rock decorated with the ancient carvings was first discovered in 1992 during a Chaco Canyon field school for students at the University of Colorado at Boulder Fort Lewis College.

It’s since come to be known as Piedra del Sol.

The petroglyph exhibits a distinctly circular shape, with a solid center that’s surrounded by jutting spirals on all sides.

‘To me it looks like a circular feature with curved tangles and structures,’ said J. McKim Malville of CU Boulder’s astrophysical and planetary sciences department.

‘If one looks at a drawing by a German astronomer of the 1860 total solar eclipse during high solar activity, rays and loops similar to those depicted in the Chaco petroglyph are visible.’

The researchers suspected a larger loop seen branching out from the circle could be a coronal mass ejection.

These eruptions send billions of tons of plasma spewing from the sun.

But, if the sun was in a quiet phase in its cycle at the time of the eclipse, a CME would be unlikely.

To find out, the experts used tree ring data and records of naked-eye observations of sunspots, as well as historical data on ‘auroral nights,’ to trace solar activity back hundreds of years.

Tree rings contain traces of the isotope carbon-14, which is caused as cosmic rays hit the Earth’s atmosphere.

The petroglyph exhibits a distinctly circular shape, with a solid center that’s surrounded by jutting spirals on all sides. Evidence of ceremonial practices at the site indicates that the free-standing rock may have been used for solstice-related activities

The petroglyph exhibits a distinctly circular shape, with a solid center that’s surrounded by jutting spirals on all sides. Evidence of ceremonial practices at the site indicates that the free-standing rock may have been used for solstice-related activities

In the petroglyph, the inclusion of several looping tendrils suggest high solar activity and even a coronal mass ejection, according to the researchers. This is illustrated in the interpretation above 

In the petroglyph, the inclusion of several looping tendrils suggest high solar activity and even a coronal mass ejection, according to the researchers. This is illustrated in the interpretation above 

WHAT ARE CORONAL MASS EJECTIONS? 

Two main types of explosions occur on the sun: solar flares and coronal mass ejections, or CMEs.

Unlike the energy and x-rays produced in a solar flare – which can reach Earth at the speed of light in eight minutes – coronal mass ejections are giant, expanding clouds of solar material that take one to three days to reach Earth.

CMEs are cloud like structures that are influenced by solar winds as they pass to Earth, found researchers from the University of Reading.

This makes their movements much harder to predict than if they were single bubble-like entities as was previously thought.

CMEs are capable of damaging satellites, destroying electronic devices and potentially exposing people at high altitude, such as astronauts and aviation crew and passengers, to cancer-causing radiation. 

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As a result, this information can be linked to sunspots – less carbon-14 means more sunspots, and higher solar activity. 

And, the analysis revealed the occurrence of a CME during the event on July 11, 1097 was certainly within the realm of possibility.

‘This was a testable hypothesis,’ Malville said.

‘It turns out the sun was in a period of very high solar activity at that time, consistent with an active corona and CMEs.’

In addition to the eclipse petroglyph, another large spiral carving on the east side of the rock was found to mark sunrise in the 15 to 17 days leading up to the June solstice.

During this time, a triangular shadow cast by a large rock on the horizon crosses through the center of the spiral.

According to the experts, this may have been used to count down to the summer solstice, and related festivities.

The east side of the rock also contains a bowl-shaped depression, where it’s thought the Chacoans left offerings, such as cornmeal.

And, on the southwest side, the rock faces a small butte on the horizon, which marks the December solstice.

The east side of the rock also contains a bowl-shaped depressions, where it’s thought the Chacoans left offerings, such as cornmeal

The east side of the rock also contains a bowl-shaped depressions, where it’s thought the Chacoans left offerings, such as cornmeal

These features, coupled with a set of carved stairs found at the rock, is indicative of the site’s ceremonial importance, according to the researchers.

‘This possible eclipse petroglyph on Piedra del Sol is the only one we know of in Chaco Canyon,’ Malville said.

‘I think it is quite possible that the Chacoan people may have congregated around Piedra del Sol at certain times of the year and were watching the sun move away from the summer solstice when the eclipse occurred.’

The free-standing rock decorated with the ancient carvings was first discovered in 1992 during a Chaco Canyon field school for students at the University of Colorado at Boulder Fort Lewis College. It’s since come to be known as Piedra del Sol

The free-standing rock decorated with the ancient carvings was first discovered in 1992 during a Chaco Canyon field school for students at the University of Colorado at Boulder Fort Lewis College. It’s since come to be known as Piedra del Sol

WHERE TO SEE THE 2017 ECLIPSE

The path of totality will stretch from Lincoln Beach, Oregon, to Charleston South Carolina.

To find out exactly when and where it will be visible, visit NASA's interactive map, and click on a city along the path.

Totality will cross the US from west to east, beginning at Lincoln Beach, Oregon, where totality will occur at 10:16 a.m. (PDT).

It will the US over roughly an hour and a half, passing through Oregon, Idaho, Wyoming, Montana, Nebraska, Iowa, Kansas, Missouri, Illinois, Kentucky, Tennessee, Georgia, and North and South Carolina.

It will end near Charleston, South Carolina, at 2:48 p.m. (EDT), according to NASA.

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And, this wasn’t the only celestial event likely viewed at Piedra del Sol.

The experts say the other two petroglyphs at the site, were likely linked to astronomical events, including a bright supernova in AD 1054 that may even have been visible in the daytime for several weeks, and a comet that passed by in AD 1066.

According to Malville, ‘The appearance of the spectacular supernova and comet may have alerted the residents of the canyon to pay attention to powerful and meaningful events in the sky.’