Athena's Web Weekly Column

Week of Jun 3rd - Jun 9th, 2005

The Stars of Ohio

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      While driving with my son Andy across country towards a rendezvous with a planetarium show we would be offering in Boulder, we took the time to explore the Ohio River Valley and some of the archaeological sites found there. We visited five on the first day, two on the second, and then traveled on to Cahokia outside of St Louis as our final stop in the Midwest. Each of these sites were constructed by the Native American Mound Builders, more precisely described as the Adena, Hopewell and Mississippian cultures. The Adena ran from about 1000 BC down to the common era, the Hopewell from 100 BC to 400 AD, and the Mississippian from about 400 AD until approximately 1300 AD.

      Each of these sites are characterized by an artificial set of mounds constructed by the indigenous cultures culminating in Cahokia's 'Monk's Mound' in Illinois which reached its peak circa 1250 AD. Cahokia Mound

      The mounds were made by individuals digging and filling baskets of earth, then carrying and dumping them onto the mound in question. Many mounds were built in stages with the level rising over time. Some are conical in shape, some flat topped, while still others seem to have been created in the form of an animal or bird. In the case of Monk's Mound, it has been approximated that 14,666,666 baskets of earth, with each basket carrying 15 cubic feet of dirt were required to construct the 22,000,000 cubic feet needed to complete this, the largest mound in North America. From its top, the entire 360 horizon of the Mississippi River Valley can be seen, with St Louis and its arch visible in the not-too-distant background.

St Louis from Cahokia       Other sites, such as Fort Hill and Fort Ancient in Ohio, show earthen walls around hill top sites which were once thought to be defensive positions, but are now being increasingly reconsidered as 'ceremonial centers'. This designation would include ceremonies which may have been timed by the motions of the stars.

      As time marches on, the notion that a number of these sites may have had astronomical overtones is gaining momentum. Alignments with the Sun, Moon and even the stars are coming under greater scrutiny and review. Andy and I spent four hours with the director of the site at Cahokia, who spoke of five different sets of circular arrangements of posts (sequential in time, not concurrent sets) which were probably used to observe heavenly motion. Not surprisingly, collectively these have been dubbed 'Woodhenge, I-V'. Based upon this notion, some post hole positions were predicted and then located in other parts of the site based upon these astronomical considerations.

      From 'Woodhenge' (see image below, at extreme left), the Sun could be seen to rise from out of the side of 'Monks Mound' at the time of the equinoxes. The Octagon Mound in Newark, Ohio has for some time been felt to observe the maxima and minima of the Moon, part of an 18.6 year cycle. If correct, it represents a sophisticated level of astronomical awareness. Although hypothetical, it would make sense that some of these ancient sites were constructed on hilltops in order to better observe the heavens, and, when hilltops were not immediately available or were not located in the correct positions, artifical mounds or 'hills' might be constructed in their place. Even the official comments from inside Cahokia's museum admit that the archetechural style is similar to that of the Maya in Central America, except that the latter used stone instead of earth.

An overview of Cahokia

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