Hopewell: Did a comet destroy this North American culture?
From 100 BC to 500 AD, a network of trade routes linked many Native American communities across North America into a single economic superstructure that is now referred to as the Hopewell tradition. Although the communities of Hopewell are culturally distinct, their sustained contact has caused them to adopt a number of uniform practices, the rise and fall of the tradition of which archaeological evidence helps us determine.
Most of what we know about the communities of Hopewell comes from excavations. They cremated their dead, although important people like hunters were often buried. Hopewell communities were also known for their earthwork structures, particularly their mounds. These “large earthen enclosures,” said archaeologist Mark Lynott in his book Ohio’s Hopewell Ceremonial Landscapes“appear to have been multifunctional places where people met perhaps for games, ceremonies, rituals, exchanges or to share news”.
At the height of the tradition, Hopewell communities were found anywhere from North Dakota to Louisiana. Unfortunately, the success of this old trading network was not to last. In the 1960s, carbon dating showed that the last of the mounds was built around 550 AD. After this date, almost all traces of this once widespread culture – from their tools to their art – apparently disappear from the archaeological record.
Several hypotheses have been put forward. An article published in the Central States Archaeological Journal speculated that the Hopewell tradition—a non-militant entity created through the voluntary participation of its members—lacks the means to prevent and resolve conflict. Excavations also revealed that many villages in Hopewell were eventually surrounded by palisades, a possible sign that their contact with the rest of the world had diminished alongside their trade in exotic products.
A new theory has turned to outer space in search of answers. In February of this year, an archaeological study published in the journal Scientific reports suggested that the cultural decline of the Hopewell tradition may have been linked to a cosmic explosion that occurred over the Ohio River Valley between AD 252 and 383. Although the communities of Hopewell are believed to have survived this catastrophic event, their way of life was bound to change significantly.
The destructive power of cosmic explosions
According to the article, cosmic explosions are created when comet fragments pass through the upper layers of our planet’s atmosphere, where high atmospheric pressure releases “a devastating high-energy shock wave over a large area.” Much has been written about the devastating effects that asteroid impacts can have on plant and animal life. However, their influence on human communities in particular remains poorly understood.
Most of what we know about the environmental impact of cosmic explosions comes from studying when they were last thought to have occurred: the so-called Tunguska event. On June 30, 1908, a 60-meter meteorite exploded above the Siberian taiga, sending a shock wave that toppled more than 80 million trees over an area of 2,150 square kilometers. While the handful of eyewitness accounts were initially met with skepticism, researchers were eventually able to corroborate their stories.
This has not been easy. The explosion took place at an altitude of at least five kilometers, completely disintegrating the comet before it hit the ground. Unable to discover an impact crater, the scientific community went in search of other smaller traces of the explosion. Nearly a century later, researchers analyzing the soil of a nearby bog came across unusually high concentrations of iridium — a rare element on Earth but relatively common in space.
If a cosmic explosion occurred over North America while the Hopewell lore was still there, it also left no impact crater. Yet archaeological digs from various communities in Hopewell have shown that the Ohio River Valley contains “an abnormally high concentration and diversity” of meteorites. Evidence of these meteorites survives in the form of fragments, which at one time were so abundant that lore people incorporated them into their jewelry, musical instruments and funeral gifts.
However, since these items were coveted and frequently traded between communities, it is difficult to determine where these fragments were originally recovered, let alone whether they came from one or more airbursts. The aforementioned study of Scientific reportswritten by a team of geologists and anthropologists from the University of Cincinnati, mapped the distribution of the meteorite fragments at 11 different Hopewell sites and concluded that the materials could not be traced to a single source. Instead, they likely came from “multiple independent” airbursts dated to AD 252-383.
The mysterious fate of the Hopewell tradition
At each site, the researchers scanned the sediments for iridium and platinum as well as two other chemical markers of meteorites: iron and silicon. Prior to their study, sediments from the Hopewell sites had barely been analyzed. Some sites have been revealed to contain higher concentrations of rare earth metals than others, suggesting that the sites with the highest concentration levels are located “at or near the epicenter” of an airburst.
Given that the environmental destruction at Tunguska was caused by a single airburst, one can only imagine the kind of damage several could have caused in the Ohio River Valley. While we still don’t know how these explosions affected the lives of members of the Hopewell tradition, we do know a thing or two about how these disasters affected their culture.
None of the communities that were part of the Hopewell tradition had a writing system, making it difficult for scholars to reconstruct the past as they saw it. Besides the incorporation of rare-earth metals into jewelry and instruments, a comet-sized earthwork found near a Hopewell site in Milford, Ohio suggests that lore people may have set up special structures to commemorate the airburst.
Memory of the disaster may also have persisted in the form of oral histories passed down from generation to generation. These memories found their way into the origin stories of a number of Hopewell communities, where they eventually took on anthropomorphized forms. The Myaamia, for example, spoke of an ancient comet called Lenipinšia, which they described as a horned serpent dropping rocks as it crossed the sky.
Shawnee and Haudenosaunee refer to an infamous comet as the sky panther – a being with the power to destroy entire forests – and the oral history of the Odawa contains the story of a time when the sun fell from the sky. If the airburst theory offered by this new article is correct, myths such as these could be interpreted much more literally than previously thought.