American researchers have found evidence of a massive 1500-year-old cosmic cataclysm, when a comet explosion over North America led to the fall of the ancient Hopewell Indian culture. This discovery may generate more interest in terms of how cosmic events may have affected the lives of prehistoric people around the world. The rapid decline of the once flourishing Hopewell Indian culture some 1,500 years ago can be attributed to the fall of debris from a near-Earth comet that exploded and disintegrated in the sky over North America, devastating the forests and villages of Native Americans. Researchers at the University of Cincinnati have found evidence of this cosmic cataclysm at 11 Hopewell archaeological sites in the Ohio Valley region of three US states. An article about them was published in the journal Scientific Reports.
The comet that flew through the Earth's atmosphere did not give rise to any large-scale crater, but left behind a lot of debris. Archaeologists have found some of them and, using radiocarbon and typological dating, determined the time of this event. A mid-air blast affected an area larger than New Jersey, causing fires over an area of 24 km2 sometime between 252 and 383 AD.
This coincides with the period when Chinese astronomers observed and documented 69 near-Earth comets, but the Native Americans preserved only oral traditions about these events.
There is an unusually high concentration and diversity of meteoric material at the Hopewell culture sites compared to other time ranges. Fragments of meteorites were identified by characteristic traces of iridium and platinum, which they contained, and in general are rarely found in terrestrial conditions. They also found a layer of charcoal, which indicates that the area was exposed to fire and intense heat.
In his lab, lead author Kenneth Tankersley, an anthropology professor at the University of Cincinnati, keeps a container of tiny meteorites collected from these sites. A variety of meteorites were found at the Hopewell sites, including stone ones, the so-called pallasites - which received their name from Pallas iron - a block found in 1749 near the city of Krasnoyarsk and described in 1773 by Russian academician Peter Palass.
“These micrometeorites have a characteristic chemical composition. When asteroids and comets explode, a large number of rare elements like platinum fall to the ground, Professor Tankersley explains. “The problem is that platinum can also be found in volcanic eruptions. Therefore, we are looking for another rare element that accompanies cosmic cataclysms and is found almost exclusively in meteorite craters - iridium. And we did find elevated concentrations of both iridium and platinum.”
The Hopewell Indians collected meteorites and extracted a malleable metal from them, which was then used in the manufacture of jewelry and musical instruments called pan flutes.
In addition to physical evidence, oral traditions have also been preserved, the authorship of which is attributed to the Indians of the disappeared Hopewell culture. And not far from the epicenter of the air explosion, there are grandiose earthworks and a mound in the form of a comet. Various Algonquian and Iroquoian tribes, descendants of the Hopewell Indians, have long remembered the disaster that befell the Earth, says Tankersley, himself a Native American.
“It's amazing that different tribes have similar stories about this event,” he says. “So, the people of Miami talk about the Horned Serpent flying through the sky and throwing stones on the ground before crashing into the river. When you see a comet flying through the air, it will look like a big snake. The Shawnee Indians commemorate the Sky Panther who destroyed the forests. Ottawa people talk about the sun fell from the sky. When a comet hits the thermosphere (the outer layer of the atmosphere that surrounds the mesosphere), it explodes like a nuclear bomb.”
The Wyandots (surviving Hurons) tell of a dark cloud that moved across the sky and was destroyed by a fire dart, adds Tankersley. The Horned Serpent is represented in the mythology of many Indian peoples, it is a kind of North American dragon associated with the forces of water, rain, lightning or thunder.
This is very similar to the 1908 descriptions of the Tunguska phenomenon given by the inhabitants of the Siberian taiga in Russia, says Tankersley.According to the most common version, it was a comet explosion over a sparsely populated area, which knocked down a forest over a vast area of 2000 km², and windows of houses were broken out within a radius of up to 200 km. Eyewitnesses reported seeing a fireball of bluish glow moving across the sky, almost as bright as the sun. This was followed by a flash and a sound like an artillery salvo. A powerful shock wave broke windows hundreds of kilometers from the epicenter and knocked people off their feet.
University of Cincinnati biology professor and co-author of the aforementioned article, David Lentz, is confident that survivors of the airburst in the fires that followed would have seen a devastated landscape: “It looks like this event caused serious damage to agriculture. The people of that time did not have suitable ways to store corn for a long time. The loss of one or two crops threatened a mass disaster. And if the explosion had knocked down trees, as in Russia, then the locals would part with walnut trees, which grew walnut and hickory, which served as a good source of food in winter. “When your corn crop dies, then you have to hope for a harvest from these trees. However, if they were all destroyed, then a real disaster would break out, ”says Lentz.
Materials scientists at the University of California also conducted scanning electron microscope studies and energy-dispersive X-ray spectrometry of sediment samples. Mass spectrometry of fragments of the preserved material was also carried out at the Center for Applied Isotope Research at the University of Georgia, and the US Geological Survey performed an analysis of stable carbon isotopes in the provided samples. The researchers also studied pollen trapped in sediment layers to understand how the comet's explosion could change the botanical landscape of the Ohio River Valley. Co-author Stephen Meyers, a UCLA geology graduate, said their discovery could generate more interest in terms of how cosmic events affected prehistoric humans around the world.