The Hopewell culture flourished across the American Midwest for centuries. A network of nations linked by trade routes, its people farmed, settled in villages, and built massive earthworks — mounds of dirt sculpted into geometric shapes.

But about the year 400, the culture began to vanish. Archaeologists have blamed its demise on war, climate change, and other factors. Scientists at the University of Cincinnati recently added another possibility: an exploding comet.

They looked at 11 Hopewell sites in Ohio and two other states. And they found several odd features. One was a layer of charcoal — the result of an extensive fire. That layer contained high concentrations of elements that are rare on Earth but common in comets and asteroids. And the layer also held lots of tiny beads of iron and silicon, which also could have come from space.

The researchers also studied oral histories of descendants of the Hopewell. They found stories of a horned serpent that dropped rocks, a sky panther that could tear down forests, and others.

The team concluded that a comet exploded high in the sky between the years 252 and 383. It started a fire that burned 9,000 square miles of forest, sprinkled meteorites across the landscape, and probably destroyed villages.

The idea needs more study before it can be confirmed. But it suggests that the Hopewell could have been doomed — at least in part — by fire from the sky.
 

Script by Damond Benningfield