Anthropology professor Kenneth Tankersley is examining two items in his office in the University of Cincinnati’s College of Arts and Sciences. | SkyNews
Anthropology professor Kenneth Tankersley is examining two items in his office in the University of Cincinnati’s College of Arts and Sciences.

Ancient comet left a lasting effect in Ohio Hopewell stories

New research shows the impact left behind by an airburst 1,500 years ago

New scientific evidence about a comet backs up generations of Indigenous, First Nations and Native American oral histories about a devastating incident around 1,500 years ago.

Researchers uncovered evidence of destruction following the airburst — or sudden explosion — of a comet fragment above the Ohio River Valley, across 11 archaeological sites in three states. The timing of the airburst appears to fall in the years 252 and 383 CE, according to radiocarbon dating. (Around the same time, Chinese astronomers also recorded 69 comets.)

The most devasted zone — roughly half the size of modern-day Nova Scotia — is the traditional homeland of the Hopewell, the ancestors of the Haudenosaunee, Miami, Ojibwe, Shawnee, Ottawa and Wyandot. 

The research was led by Kenneth Barnett Tankersley, an enrolled member of the Piqua Shawnee of Alabama who is an anthropology professor at the University of Cincinnati in Ohio.

“I thought that the only way to learn about my culture was to become a scientist, and to examine my own past, my own people, through science,” he told SkyNews. As he continued his academic education, however, he noticed many Native American scholars arguing for the validity of including oral histories in scientific research.

Kenneth Tankersley uses a magnet to show how micrometeorites collected at 11 Hopewell sites contain metals such as iron. University of Cincinnati researchers found they also contained high levels of platinum and iridium. (University of Cincinnati)

Notable scholars he raised included Vine Deloria, Jr. — a member of the Standing Rock Sioux and best known for a 1969 book called Custer Died for Your Sins but who has written about ancient comets — and Santa Clara Pueblo scholar Gregory Cajete, who wrote the 2016 book Native Science.

Cajete in particular, Tankersley said, argues that Native Americans have always been scientists, especially in astronomy, and that the knowledge is passed down through oral histories and songs.

In Tankersley’s childhood, for example, he remembers being told of the Uktena, the Great Sky Serpent or Great Horned Serpent. “His head was as bright and brilliant as the Sun, and his body has scales that were made of sparkling fire,” Tankersley said.

He added that the story made him wonder how he could pursue the matter archaeologically and find evidence of some event in the region.

“Archaeologically, there’s one time period and one geographic area where we find a concentration of meteorites — and that’s what we call the Middle Woodland cultural period,” he explained. This period ran from 2,400 to 1,000 years ago.

The United States Army Corps of Engineers in 1823 surveyed an ancient Hopewell site on the Little Miami River in southwest Ohio today known as the Milford Earthworks. The surveyor found Hopewell mounds standing five to 10 feet tall, including one in the shape of a comet. (United States National Archives) | SkyNews
The United States Army Corps of Engineers in 1823 surveyed an ancient Hopewell site, today known as the Milford Earthworks, on the Little Miami River in southwest Ohio. The surveyor found Hopewell mounds standing five to 10 feet tall, including one in the shape of a comet. (United States National Archives)

Tankersley focused on areas inhabited by a group we today call the Hopewell, a Native American group unfortunately named after a farm upon which their remains were excavated in 1890. (The moniker is still used for the community as we do not know what they call themselves.) One of the Hopewell’s distinctive attributes was earthworks arranged to describe events, rituals and other items of importance to their culture.

Relevant to space, there is also a large concentration of meteorites on Hopewell sites — nickel-iron and stony, to name a few. Originally, the meteorites were interpreted as precious stones that were traded like other exotic materials from the Gulf of Mexico, the Atlantic Coast, the Great Plains and modern-day Canada, Tankersley said.

Hopewell sites were first excavated in the 1800s, when archaeological practice was focused on gathering artifacts and not on examining the surrounding environment. The dirt, for example, was not examined, Tankersley said — and to be fair, scientists of the day did not have nearly the analysis tools we have available in the 2020s.

So when he and his team went back to these previously excavated sites, they focused on the soil and found a high concentration of the (usually) rare elements iridium and platinum, along with a charcoal layer showing that the area had experienced a lot of fire and heat. These all were signs that the site was altered by and exposed to an airburst, Tankersley said.

University of Cincinnati researchers collect sediment samples from an ancient Hopewell village along the Great Miami and Ohio Rivers. From left, they are anthropology student Louis Herzner, biology student Stephanie Meyers, Kenneth Tankersley and alumnus Stephen Meyers. (Larry Sandman) | SkyNews
University of Cincinnati researchers collect sediment samples from an ancient Hopewell village along the Great Miami and Ohio Rivers. From left, they are anthropology student Louis Herzner, biology student Stephanie Meyers, Kenneth Tankersley and alumnus Stephen Meyers. (Larry Sandman)

What also struck Tankersley and his team was the comet-shaped mound made near what they determined was the centre of the airburst, at a Hopewell site today called the Milford Earthworks.

“We dug underneath the earthwork, and that’s where we found evidence of the event. In other words, the comet-shaped earthwork was built on top of the evidence that we found, but more importantly, the angle of the earthwork was absolutely identical to the angle of the [comet] ejecta,” Tankersley said.

He added that the iridium, platinum and micrometeorites that Tankersley and his team found — which all came from the dropping comet — were on the exact same angle as the earthwork. “They [the Hopewell] were communicating with the symbols in their earthwork,” Tankersley said. “They built the comet-shaped earthwork above their village to symbolize the sky.”

United States Geological Survey geologist and co-author James Jorden also tracked a carbon isotope (or different form of carbon) to track changes in vegetation, which showed the comet had a lasting effect on the vegetation. University of Cincinnati archaeobotanist and co-author, David Lentz believed that it would have impacted the agricultural produce and forced the people to pivot to foraging and hunting while hoping that their crops would recover.

While the Hopewell eventually declined, the causes of the decline are complex and cannot be traced to a single event. That said, the comet would have made things quite difficult for them, Tankersley said.

A study based on the research was published in Nature’s Scientific Reports on February 1.

This biweekly column by Canadian science and space journalist Elizabeth Howell focuses on a trending news topic in Canadian astronomy and space.

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